JP2016122964A - Electronic apparatus and control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electronic apparatus which is reset from error state, when a decoding error is generated while decoding the image data transmitted from the electronic apparatus to a display device, and to provide a control method.SOLUTION: An electronic apparatus has generation means 104 for generating slice image data, i.e., the image data in a first slice region determined based on the difference of the image data of a plurality of frames, coding means 105 for compression encoding the slice image data, transmission means 106 for transmitting the slice image data subjected to compression encoding to a display device, reception means 107 for receiving a retransmission request including the information indicating the first slice region, when a decoding error occurs in the slice image data, and control means 109 for controlling so that the image data in a second slice region including a region corresponding to the first slice region in the second frame after the first frame corresponding to the first slice region, when the retransmission request is received.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an electronic apparatus and a control method for processing an image displayed on a display device.

  Patent Document 1 describes a method of transmitting video data after compression-encoding it using the MPEG method.

JP-A-9-266576

  When video data is transmitted from an electronic device such as a personal computer to the display device, a data error occurs in the video data on the transmission path, and decoding becomes impossible during decoding of the video data received by the display device, resulting in a decoding error. There is a case. For example, when a decoding error occurs during decoding of video data, the display device requests the electronic device to retransmit image data for one frame. In this case, the display device can restart the display of the video data in which the decoding error has occurred by restarting the display of the video data from the image data for one frame retransmitted from the electronic device.

  However, in this case, until the display device receives the image data for one frame retransmitted from the electronic device, the display device stops the video data being displayed, and the image data for one frame retransmitted from the electronic device is displayed. The video data display is resumed after reception. Therefore, there is a problem that the timing at which the display device resumes displaying the video data is delayed. When the timing for resuming the display of the video data is delayed, the user feels that the display image changes slowly. Therefore, when a decoding error occurs during decoding of the video data transmitted from the electronic device to the display device, it is required to be able to recover from the error state as soon as possible.

  Therefore, an object of the present invention is to enable recovery from an error state when a decoding error occurs during decoding of image data transmitted from an electronic device to a display device.

In order to solve the above-described problem, an electronic apparatus according to the present invention generates generation unit that generates slice image data that is image data in a first slice region determined based on differences between image data of a plurality of frames. Encoding means for compressing and encoding the slice image data, transmitting means for transmitting the compression encoded slice image data to a display device, and when a decoding error occurs in the slice image data, Receiving means for receiving a retransmission request including information indicating a first slice area from the display device; and, when the retransmission request is received, a second after a first frame corresponding to the first slice area Control for controlling image data in a second slice area including an area corresponding to the first slice area in two frames to be transmitted to the display device And having a stage.
The program according to the present invention includes a generating unit that generates slice image data that is image data in a first slice region determined based on a difference between image data of a plurality of frames, and the slice image data. An encoding means for compressing and encoding, a transmitting means for transmitting the compression-encoded slice image data to a display device, and the first slice area when a decoding error occurs in the slice image data Receiving means for receiving a retransmission request including information from the display device; and, if the retransmission request is received, the first in a second frame after the first frame corresponding to the first slice region Control means for controlling image data in a second slice area including an area corresponding to the slice area to be transmitted to the display device Is a program for causing the performance.
The control method according to the present invention includes a generation step of generating slice image data that is image data in a first slice area determined based on differences between image data of a plurality of frames, and compression encoding the slice image data An encoding step to be converted, a transmission step to transmit the compression-encoded slice image data to a display device, and information indicating the first slice area when a decoding error occurs in the slice image data A reception step for receiving a retransmission request including from the display device; and, if the retransmission request is received, the first slice in a second frame after the first frame corresponding to the first slice region A control step for controlling image data in a second slice area including an area corresponding to the area to be transmitted to the display device; Characterized in that it.

  ADVANTAGE OF THE INVENTION According to this invention, when a decoding error generate | occur | produces during decoding of the image data transmitted to the display apparatus from the electronic device, it can reset from an error state.

(A) is a figure for demonstrating the structure of the display system 1 in Embodiment 1, (b) is a figure for demonstrating the outline | summary of operation | movement when a decoding error generate | occur | produces. 2 is a diagram for explaining a configuration of an electronic device 100. FIG. It is a figure for demonstrating the example of a difference area. 4 is a diagram for explaining a configuration of a display device 200. FIG. It is a figure for demonstrating the structure of the slice image data A containing the image data in all the area | regions of 1 frame. It is a figure for demonstrating the relationship between the slice image data A and a display screen. It is a figure for demonstrating the structure of the slice image data B containing the image data in the one part area | region of 1 frame. It is a figure for demonstrating the relationship between the slice image data B and a display screen. 12 is a flowchart for explaining processing performed in electronic device 100 and display device 200 when a decoding error occurs. 6 is a diagram for explaining an example of transition of a display image on the display device 200. FIG. 10 is a flowchart for explaining processing performed by electronic device 100 and display device 200 in the second embodiment. It is a table | surface for demonstrating the relationship between output resolution and an output frame rate, and predetermined size. 6 is a diagram for explaining an example of transition of a display image on the display device 200. FIG. It is a figure for demonstrating the structure of the electronic device 300 in Embodiment 3. FIG. It is a flowchart for demonstrating the process which specifies a synthetic | combination difference area | region. 14 is a flowchart for explaining a decoding error return process in the third embodiment. FIG. 10 is a diagram for describing a configuration of a display device 400 according to a fourth embodiment. 12 is a flowchart for explaining decoding error recovery processing in the display device 400. 11 is a diagram for explaining an example of transition of a display image on the display device 400. FIG. 10 is a flowchart for explaining a decoding error recovery process in the fifth embodiment. It is a figure for demonstrating the example of a division area. FIG. 10 is a diagram for explaining an example of transition of a display image in the fifth embodiment.

[Embodiment 1]
FIG. 1A is a diagram for explaining the configuration of the display system 1 according to the first embodiment. The display system 1 includes an electronic device 100 and a display device 200. The electronic device 100 and the display device 200 are connected via, for example, a cable 150 corresponding to the DisplayPort standard. The cable 150 includes a number of signal lines corresponding to the resolution of video data transmitted from the electronic device 100 to the display device 200.

  The electronic device 100 is, for example, a personal computer, a mobile phone, or an imaging device, and transmits video data to be displayed on the display device 200 to the display device 200. For example, the electronic device 100 can transmit video data having a resolution of 4096 × 2160 (4K2K) and video data having a resolution of 8192 × 4320 (8K4K) to the display device 200.

  In the following first to sixth embodiments, a case will be described in which the electronic device 100 compresses and transfers video data using a DSC (Display Stream Compression) method. The DSC system is a system defined by VESA (Video Electronics Standards Association). In the following first to sixth embodiments, the electronic apparatus 100 generates all the areas of the first frame of video data as slice areas, and generates slice image data that is image data in the slice areas. Then, the electronic device 100 compresses and encodes the slice image data according to a predetermined compression encoding method (lossless compression encoding method or lossy compression encoding method), and the compression-encoded slice image data is displayed on the display device 200. Transmit via cable 150. Thereafter, the electronic device 100 extracts a slice area including an area where a difference has occurred between the image data of the new frame and the image data of the previous frame from the new frame, and the image data in the slice area Is generated. The electronic device 100 compresses and encodes the slice image data with a predetermined compression encoding method (lossless compression encoding method or lossy compression encoding method), and cable the compression encoded slice image data to the display device 200. 150 to transmit. Hereinafter, the image data in the slice area is referred to as slice image data, and the transmission of the slice image data is referred to as slice transfer.

  When image data in a partial area of one frame is slice-transferred, the electronic device 100 reduces the amount of image data to be transferred as compared to a case where image data in the entire area of one frame is transferred. Can be reduced. Therefore, when image data in a partial area of one frame is slice-transferred, the compression rate can be lowered as compared with a case where image data in all areas of one frame is transferred. As a result, the image quality of the image displayed on the display device 200 can be improved by executing the slice transfer for the image data in a partial area of one frame.

  Here, if a data error occurs during transmission of slice image data from the electronic device 100 to the display device 200, the display device 200 generates a decoding error due to the inability to decode, and correctly converts the compression-encoded slice image data. It may not be possible to decrypt. When such a decoding error occurs, the display apparatus 200 transmits a request for resending the slice image data in which the decoding error has occurred to the electronic device 100. When receiving a retransmission request from the display apparatus 200, the electronic device 100 specifies an error slice area that is a slice area corresponding to slice image data in which a decoding error has occurred. Thereafter, the electronic device 100 generates slice image data that is image data in a region including at least the error slice region from the image data of the new frame. The electronic device 100 compresses and encodes the generated slice image data and transmits it to the display device 200.

  FIG. 1B is a diagram for explaining the outline of the operation when a decoding error occurs. The electronic device 100 sequentially generates frames F1, F2, F3, and F4 at predetermined intervals from the video data. Frames F1, F2, F3, and F4 include images of the moving object a. The electronic device 100 cuts out a rectangular area including an area in which a difference is generated between the image data of the adjacent first and second frames from the second frame as a slice area, so that the image data in the slice area Is generated.

  The electronic device 100 transmits slice image data V1 of the slice area A1 including the image area of the object a to the display device 200 in the frame F1. The display device 200 displays an image E1 in which the slice image data V1 is inserted in the slice area A1 in the frame that was displayed when the slice image data V1 was received.

  The electronic device 100 extracts a difference area from the frame F1 as a slice area A2 in the frame F2. In the example illustrated in FIG. 1B, the slice area A2 is an area obtained by combining the slice area A1 and the area including the object a. The electronic device 100 extracts the slice area A2 from the frame F2, generates slice image data V2 that is image data in the slice area A2, and transmits the generated slice image data V2 to the display device 200.

  If a data error occurs during transmission of the slice image data V2 and a decoding error occurs during decoding in the display device 200, the display device 200 cannot display an image based on the slice image data V2, For example, the image E2 in the same state as the image E1 is displayed. Then, the display device 200 transmits a retransmission request to the electronic device 100 for the slice image data V2 in which the decoding error has occurred.

  In the example illustrated in FIG. 1B, the electronic device 100 receives the retransmission request after transmitting the frame F3. Therefore, the electronic device 100 transmits slice image data V3 that is image data for processing in response to the retransmission request. When receiving the slice image data V3, the display device 200 displays an image E3 in which the slice area A3 in the image E2 is replaced with the slice image data V3. Since the slice area A3 does not include a part of the slice area A1, a part of the slice area A1 remains unupdated in the image E3 in the example illustrated in FIG.

  Subsequently, the electronic device 100, in the frame F4 after receiving the retransmission request, includes a slice area A2 corresponding to the error slice area and a slice area A4 corresponding to the difference area between the frames F3 and F4. Create a region. The electronic device 100 extracts a composite slice area from the frame F4, generates slice image data V4 that is image data in the composite slice area, and transmits the generated slice image data V4 to the display device 200.

  When the display device 200 receives the slice image data V4, the display device 200 displays the image E4 in which the combined slice area in the image E3 is replaced with the slice image data V4. In the image E4, the slice image data V4 extracted from the new frame F4 is reflected in the slice area A2 included in the slice image data V2 in which the decoding error has occurred. Since the synthesized slice area also includes the slice area A1, the partial image of the slice area A1 remaining in the image E3 is also updated.

As described above, the display system 1 does not need to increase the compression rate of the slice image data to be transferred by reducing the amount of data transferred from the electronic device 100 to the display device 200, and thus displays a high-quality image. Can be made. The display system 1 can recover from the decoding error in a short time even when a data error occurs in the transmitted slice image data and a decoding error occurs during decoding in the display device 200. .
Hereinafter, the configuration and operation of the electronic device 100 and the display device 200 will be described in detail.

  FIG. 2 is a diagram for explaining the configuration of the electronic device 100. The electronic device 100 includes a storage device 101, a difference extraction unit 102, a region determination unit 103, a slice image data generation unit 104, an encoding unit 105, a transmission unit 106, and a reception unit, each connected to an internal bus. 107, an operation unit 108, and a control unit 109.

  The storage device 101 stores video data that the electronic device 100 transmits to the display device 200. The storage device 101 is, for example, a hard disk device or a semiconductor memory. The storage device 101 may be configured by a storage medium that is detachable from the electronic device 100. Note that the electronic device 100 may use a storage device connected to a network as the storage device 101 without incorporating the storage device 101.

  The difference extraction unit 102 reads out image data in units of frames from the storage device 101, extracts differences between image data of a plurality of adjacent frames, and indicates a difference area that is a rectangular area that includes all the pixels in which the differences occur. Generate information. The difference extraction unit 102 has a buffer capable of storing image data of two or more frames in order to compare image data of a plurality of adjacent frames.

  FIG. 3 is a diagram for explaining an example of the difference area. When the horizontal direction of the image data for one frame is the x axis, the vertical direction is the y axis, and the upper left position is the origin (0, 0), the difference information is the coordinates of one vertex of the difference area (x1, y1). ), The length w of the difference region in the x-axis direction and the length h in the y-axis direction.

  The difference extraction unit 102 outputs the generated difference information to the region determination unit 103. Further, the difference extraction unit 102 sequentially outputs the image data of the frames read from the storage device 101 to the slice image data generation unit 104. The difference extraction unit 102 converts the resolution of the frame read from the storage device 101 when the resolution of the frame read from the storage device 101 and the resolution of the image that can be displayed by the display device 200 are different. In this way, the difference extraction unit 102 converts the video data corresponding to the resolution equal to the resolution of the image that can be displayed by the display device 200, and stores the converted video data in the buffer.

  Based on the difference information input from the difference extraction unit 102 and the information indicating the error slice region included in the retransmission request received from the display device 200 via the reception unit 107, the region determination unit 103 starts from a new frame. The composite slice area to be cut out is determined. The area determination unit 103 outputs information indicating the combined slice area to the slice image data generation unit 104. Note that when the electronic device 100 has not received a retransmission request from the display device 200, the combined slice area is equal to the difference area. When transmitting the first frame of the video data to the display device 200, the region determining unit 103 determines all the regions of the first frame of the video data as the composite slice region.

  Based on the information indicating the composite slice area input from the area determination unit 103, the slice image data generation unit 104 uses the image data in the composite slice area from the image data of the new frame input from the difference extraction unit 102. Some slice image data is generated. When no decoding error has occurred in the display device 200, the synthesized slice area is equal to the difference area, and therefore the slice image data generation unit 104 includes a slice area determined based on the difference between the image data of a plurality of frames. Slice image data that is image data is generated. When transmitting the first frame of the video data to the display device 200, the slice image data generation unit 104 sets the image data in all areas of the first frame of the video data as slice image data. The slice image data generation unit 104 outputs the generated slice image data to the encoding unit 105.

  The encoding unit 105 encodes the slice image data input from the slice image data generation unit 104. For example, the encoding unit 105 compresses and encodes the slice image data by encoding the slice image data according to a predetermined compression encoding method (lossless compression encoding method or lossy compression encoding method). The encoding unit 105 outputs the slice image data after compression encoding to the transmission unit 106.

  The transmission unit 106 transmits the slice image data input from the encoding unit 105 to the display device 200 via the cable 150. For example, the transmission unit 106 transmits slice image data via the main data channel line in the cable 150. The transmission unit 106 transmits specifying information including coordinate data for specifying a slice region together with slice image data.

  The transmission unit 106 transmits slice image data that is image data in the slice area determined based on the difference between the image data of a plurality of frames. When the reception unit 107 receives a retransmission request from the display device 200, the transmission unit 106 transmits slice image data including an error slice area in a frame after the frame corresponding to the slice image data in which a decoding error has occurred. To do.

  The receiving unit 107 receives a retransmission request transmitted from the display device 200 via an AUX channel line (auxiliary channel line) in the cable 150. The retransmission request includes identification information for identifying an error slice area in slice image data in which a decoding error has occurred. Note that the information for specifying the error slice area is, for example, information indicating the area of the slice image data transmitted from the transmission unit 106 to the display device 200 together with the slice image data.

  The operation unit 108 is, for example, a keyboard and a mouse, and receives an instruction from the user. The operation unit 108 receives, for example, a video data playback instruction, an instruction regarding whether or not to execute slice transfer, and an instruction regarding output setting. The instruction relating to the output setting is, for example, an instruction relating to setting of the resolution and frame rate of the image displayed on the display device 200.

  The control unit 109 is a CPU (Central Processing Unit), for example, and controls each component of the electronic device 100 by executing a program stored in a storage medium (hard disk device, semiconductor memory, etc.). The control unit 109 controls each unit of the electronic device 100 according to a user instruction input via the operation unit 108.

  For example, when receiving a video data playback instruction via the operation unit 108, the control unit 109 instructs the difference extraction unit 102 to start reading video data specified by the playback instruction. Further, when the control unit 109 receives an instruction regarding whether or not to execute slice transfer, the control unit 109 instructs the difference extraction unit 102 to perform difference extraction or to perform through processing without performing difference extraction. In addition, the control unit 109 instructs the slice image data generation unit 104 to cut out the slice area or perform the through process without cutting out. Further, the control unit 109 instructs the encoding unit 105 to perform the encoding process or to perform the through process without performing the encoding process.

  The control unit 109 also determines the resolution and frame rate of the video data to be transmitted to the display device 200 based on the device information acquired from the display device 200 and the instruction regarding the output setting received from the user via the operation unit 108. To decide. The device information of the display apparatus 200 can be acquired from, for example, EDID (Extended Display Identification Data) included in the display apparatus 200. The EDID included in the display device 200 includes, for example, information regarding the resolution supported by the display device 200. The determined resolution and frame rate are notified to the slice image data generation unit 104 and the transmission unit 106.

Next, the configuration of the display device 200 will be described.
FIG. 4 is a diagram for explaining the configuration of the display device 200. The display device 200 includes a receiving unit 201, a decoding unit 202, an image composition unit 203, a display unit 204, a transmission unit 205, an operation unit 206, and a control unit 207, which are connected via an internal bus. .

  The receiving unit 201 receives the slice image data transmitted from the electronic device 100 via the main data channel line in the cable 150. The receiving unit 201 outputs the received slice image data to the decoding unit 202 in units of frames.

  The decoding unit 202 decodes the slice image data input from the receiving unit 201. The decoding unit 202 outputs the decoded slice image data to the image composition unit 203. The decoding unit 202 discards the slice image data in which the decoding error has occurred and decodes the decoding error when a decoding error due to inability to decode occurs during decoding and the decoding process cannot be continued. Is notified to the transmission unit 205.

  The decoding unit 202 outputs, to the image synthesis unit 203, identification information for identifying a slice region that is attached to the decoded slice image data. Also, when a decoding error occurs during decoding, the decoding unit 202 outputs, to the transmission unit 205, specific information associated with a frame including slice image data in which the decoding error has occurred.

  The image synthesis unit 203 synthesizes the slice image data input from the decoding unit 202 and the display image data displayed when the slice image data is input from the decoding unit 202. The image synthesis unit 203 has a buffer for synthesizing slice image data and display image data.

  For example, the image composition unit 203 identifies a slice region in the display image region based on the identification information input from the decoding unit 202. The image composition unit 203 performs composition by updating only the slice area in the display image. Note that the image composition unit 203 performs image processing by adjusting brightness, contrast, gradation, and chromaticity on the combined image data. The image composition unit 203 outputs an image based on the image data after composition or the image data after image processing to the display unit 204.

  The display unit 204 includes a frame buffer and a display panel, and stores the image data input from the image composition unit 203 in the frame buffer. Then, the image data is read out at a predetermined refresh rate and displayed on the display panel. The display panel includes, for example, a liquid crystal panel, an organic EL panel, and the like.

  When a decoding error occurs in the decoding process in the decoding unit 202, the transmission unit 205 retransmits the slice image data in which the decoding error has occurred to the electronic device 100 via the AUX channel line in the cable 150. Output the request. The transmission unit 205 outputs a retransmission request including specific information input from the decoding unit 202.

The operation unit 206 is a switch that receives an operation from the user.
The control unit 207 controls each component of the display device 200 according to a user instruction received by the operation unit 206. The user instruction is, for example, an instruction related to image processing. Upon receiving an instruction regarding image processing, the control unit 207 instructs the image composition unit 203 to perform image processing on the synthesized image.

  With reference to FIGS. 5 to 8, the configuration of slice image data transmitted from the electronic device 100 to the display device 200 will be described. FIG. 5 is a diagram for explaining a configuration of slice image data A including image data in all areas of one frame. FIG. 6 is a diagram for explaining the relationship between the slice image data A and the display screen. FIG. 7 is a diagram for explaining the configuration of slice image data B including image data in a partial area of one frame. FIG. 8 is a diagram for explaining the relationship between the slice image data B and the display screen.

  VFP in FIGS. 5 to 8 is a vertical frame period. VBP is a vertical blanking period. ALP is an active line period. HLP is a horizontal line period. HBP is a horizontal blanking period. APP is an active pixel period.

  As shown in FIG. 5, the slice image data A includes a BS signal 560 indicating the start of a blanking period, a BE signal 570 indicating the end of the blanking period, image data 580, and specific information 590. The identification information 590 includes at least information indicating the resolution of the image data 580, the start line number, the end line number, the start pixel number, the end pixel number, the presence / absence of DSC encoding, and the presence / absence of slice transfer.

  When the image data 580 corresponds to 4K2K video data, the resolution is 4096 × 2160. As shown in FIG. 6, when the image data 580 corresponds to the entire area of the display screen of the display device 200, the start line number of the image data 580 included in the specific information 590 is “0”, and the end of the image data 580 The line number is “2159”. Similarly, the start pixel number is “0”, the end pixel number is “4095”, the DSC encoding is “none”, and the slice transfer is “none”.

  Similarly to the slice image data A shown in FIG. 5, the slice image data B shown in FIG. 7 also includes a BS signal 561 indicating the start of the blanking period, a BE signal 571 indicating the end of the blanking period, the image data 581, and the identification. It consists of information 591. The identification information 591 includes at least information indicating the resolution of the image data 581, the start line number, the end line number, the start pixel number, the end pixel number, the presence / absence of DSC encoding, and the presence / absence of slice transfer. The specific information 591 is used as specific information for specifying a slice region corresponding to the slice image data B.

  The position of the image data 581 in the slice image data B shown in FIG. 7 is different from the position of the image data 580 in the slice image data A shown in FIG. For example, the image data 580 occupied a period between the BE signal 570 and the BS signal 560, whereas the image data 581 is a partial period between the BE signal 571 and the BS signal 561. Only included.

  FIG. 8 shows an area of the image data 580 in the slice image data A (area surrounded by a broken line) and an area of the image data 581 in the slice image data B. It can be seen that the image data 581 corresponds to a partial area of the display screen of the display device 200.

  When the image data 581 corresponds to 4K2K video data, the resolution is 4096 × 2160. When the image data 581 corresponds to a partial area of the display screen as shown in FIG. 8, for example, the start line number of the image data 581 included in the specific information 591 is “400”, and the end of the image data 581 The line number is “1479”. Similarly, the start pixel number is “2048”, the end pixel number is “3967”, the DSC encoding is “Yes”, and the slice transfer is “Yes”.

Next, the decoding error return process in the first embodiment will be described.
FIG. 9 is a flowchart for explaining processing performed in the electronic device 100 and the display device 200 when a decoding error occurs during the decoding of slice image data.

  When the decoding unit 202 of the display device 200 detects that a decoding error has occurred due to inability to decode during decoding of the slice image data input from the receiving unit 201, the decoding unit 202 discards the slice image data being decoded. (S100). Thereafter, the decoding unit 202 determines whether or not the slice image data in which the decoding error has occurred includes image data for one frame, based on the information included in the specific information 591 (S101). Here, when the slice image data in which the decoding error has occurred includes image data for one frame (Yes in S101), the decoding unit 202 retransmits the image data for one frame via the transmission unit 205. Request. When the slice image data in which the decoding error has occurred does not include image data for one frame (No in S101), the decoding unit 202 receives the identification information 591 and information indicating that the decoding error has been detected. Notify the transmission unit 205.

  When the transmission unit 205 receives the identification information 591 and information indicating that a decoding error has been detected, the transmission unit 205 specifies the slice area of the slice image data in which the decoding error has occurred, to the electronic device 100. The retransmission request including the specific information is transmitted (S102). For example, the transmission unit 205 transmits a retransmission request including the specific information 591 as the specific information.

  When receiving the retransmission request from the transmission unit 205, the reception unit 107 of the electronic device 100 inputs error slice region information indicating the slice region specified by the specific information to the region determination unit 103 (S103). Thereafter, the area determination unit 103 acquires difference information of the next frame to be transferred from the difference extraction unit 102 (S104). The area determination unit 103 extracts a region including both the error slice area indicated by the error slice area information acquired in S103 and the difference area indicated by the difference information acquired in S104 from a new frame. (S105).

  The slice image data generation unit 104, based on the information indicating the composite slice region input from the region determination unit 103, from the image data of the frame input from the difference extraction unit 102, slices that are image data in the composite slice region Generate image data. The slice image data generated by the slice image data generation unit 104 is encoded by the encoding unit 105 and transmitted to the display device 200 via the transmission unit 106 (S106). If the error slicing area information associated with the retransmission request is not acquired in S103, the area determining unit 103 generates slice image data using the difference area based on the difference information acquired in S104 as a combined slice area. Note that when there is no difference between adjacent frames, only the error slice area is included in the combined slice area.

  Subsequently, the reception unit 201 of the display device 200 receives the slice image data transmitted by the transmission unit 106 (S107). The display device 200 can update the image in the error slice area to an image in a new frame by decoding the received slice image data and displaying it on the display unit 204.

  FIG. 10 is a diagram for explaining an example of display image transition in the display device 200. FIG. 10A shows an example of display image transition when no decoding error occurs, and FIG. 10B shows an example of display image transition when a decoding error occurs. Show.

  FIG. 10A shows a state where the image of the automobile is moving rightward while the display image transitions from T100 to T103. On the other hand, in FIG. 10B, a decoding error has occurred during decoding of the slice image data V101 to be displayed at T111, so that the display image T111 has the same slice image data V100 as the display image T110. Is displayed.

  Subsequently, in the display image T112, the slice image data V102 newly received by the display device 200 is displayed. The slice image data V102 does not include an area where there is no difference between the display image T111 and the display image T112 in FIG. Therefore, a part of the slice image data V101 is displayed on the left end of the display image T112 without being erased.

  After that, when the display device 200 receives the slice image data V104 including the region where the error slice region and the difference region are combined, as shown in the display image T113, the slice image data remaining in the display image T112. A part of V101 is overwritten. As a result, the same image as the display image T103 in FIG. 10A is displayed on the display image T113 in FIG.

  As described above, the electronic device 100 according to the first embodiment compresses and encodes the slice image data corresponding to the slice area determined based on the difference between adjacent frames, and transfers the slice image data to the display device 200. Then, even if a decoding error occurs during decoding of the compression-encoded slice image data, the electronic device 100 can generate new slice image data including a slice area corresponding to the slice image data in which the decoding error has occurred. Can be transferred. As a result, the display delay when the decoding error occurs can be eliminated and restored in a short time. As described above, the display system 1 according to the first embodiment can display a high-quality image and suppress a display delay when a decoding error occurs.

[Embodiment 2]
In the first embodiment, when a decoding error occurs during the decoding of the slice image data received by the display device 200, the electronic device 100 transmits slice image data corresponding to the combined slice region to the display device 200. did. Here, the composite slice area includes a difference area between the new frame and the previous frame, and an error slice area. However, if the combined slice area is too large, it is necessary to increase the compression rate, so that the image quality degradation may exceed the allowable range. Therefore, the second embodiment is different from the first embodiment in that the electronic device 100 performs different processing based on the size of the combined slice area. Here, as the “size of the slice area” in the second embodiment, for example, “the number of pixels included in the slice area” can be used.

  For example, when the size of the synthesized slice area is equal to or smaller than a predetermined size that allows image quality degradation, the area determining unit 103 determines the synthesized slice area as an area to be cut out from a new frame. The slice image data generation unit 104 generates slice image data that is image data in the combined slice region. On the other hand, when the synthesized slice area is larger than a predetermined size that allows image quality degradation, the area determination unit 103 selects an area of a predetermined size that includes at least a part of the error slice area from among the synthesized slice areas. The region to be cut out from the new frame is determined. The slice image data generation unit 104 generates slice image data, which is image data within an area of a predetermined size, from the frame image data.

  When the area determining unit 103 determines an area of a predetermined size as an area to be cut out from a new frame, an area that is not included in the area of the predetermined size among the synthesized slice areas (hereinafter referred to as a remaining slice area). Ask. Then, the region determination unit 103 determines a rectangular region including the difference region included in the remaining slice region as a new combined slice region. The area determination unit 103 repeats this process until the new combined slice area is equal to or smaller than a predetermined size, thereby suppressing deterioration in the image quality of the slice image data including the error slice area to be retransmitted in the decoding error recovery process. can do.

  FIG. 11 is a flowchart for explaining processing performed by the electronic device 100 and the display device 200 according to the second embodiment. S200 to S204 in FIG. 11 are the same processes as S100 to S104 in FIG. Therefore, here, the processing after S205 will be described.

  In S205, the region determination unit 103 temporarily determines a region including the error slice region acquired in S203 and the difference region acquired in S204 as a new combined slice region. In addition, when the processing of S211 described later is performed, the region determination unit 103 temporarily determines a region including the remaining slice region obtained in S211 and the difference region acquired in S204 as a new composite slice region. (S205).

  Subsequently, the region determination unit 103 compares the provisional composite slice region obtained in S205 with a predetermined size (S206). The predetermined size is set in advance for each output resolution and output frame rate, and is a size that can allow image quality deterioration due to compression coding.

  FIG. 12 is a table for explaining the relationship between the output resolution and output frame rate and a predetermined size. When the resolution is 8K4K and the frame rate is 60 Hz, the predetermined size is D1. When the resolution is 8K4K and the frame rate is 50 Hz, the predetermined size is D2. When the resolution is 4K2K and the frame rate is 60 Hz, the predetermined size is D3.

  The predetermined size may be further subdivided by a combination of a signal format (RGB or YUV), a sampling rate (4: 4: 4 or 4: 2: 2) in addition to the output resolution and the output frame rate. Further, the predetermined size may be changed in response to a user instruction from the operation unit 108.

  Returning to FIG. 11, in S206, when the synthesized slice area is equal to or smaller than the predetermined size (Yes in S206), the area determining unit 103 determines the synthesized slice area temporarily determined in S205 as an area to be cut out from a new frame. Then, the region determination unit 103 notifies the slice image data generation unit 104 of composite region information for specifying the composite slice region (S207). The slice image data generation unit 104 generates slice image data that is image data in the combined slice region from the image data of the frame input from the difference extraction unit 102 based on the combined region information input from the region determination unit 103. Generate. The generated slice image data is encoded by the encoding unit 105 and transmitted to the display device 200 via the transmission unit 106 (S208).

  In S206, when the temporary slice area is larger than the predetermined size (No in S206), the area determination unit 103 sets a predetermined size area including the error slice area as a new composite slice from the temporary composite slice area. Decide on an area. The region determination unit 103 notifies the slice image data generation unit 104 of information for specifying the determined region (S209).

  The slice image data generation unit 104 is a slice that is image data in an area of a predetermined size from the image data of the frame input from the difference extraction unit 102 based on the combined slice area information input from the area determination unit 103. Generate image data. The generated slice image data is encoded by the encoding unit 105 and transmitted to the display device 200 via the transmission unit 106 (S210).

  Thereafter, the area determination unit 103 obtains a remaining slice area obtained by subtracting a predetermined size from the temporary slice area (S211). When the area determination unit 103 obtains the remaining slice area, the process returns to S204, and the processes after S204 are continued.

  FIG. 13 is a diagram for explaining an example of display image transition in the display device 200. FIG. 13A shows the transition of the display image when the size of the combined slice area is equal to or smaller than a predetermined size. FIG. 13B shows the transition of the display image when the size of the composite slice area is larger than a predetermined size.

  In the display image T200 in FIGS. 13A and 13B, the slice image data V200 after decoding is displayed. Thereafter, it is assumed that a decoding error has occurred during decoding of the slice image data V201 to be displayed on the display image T201. In this case, the slice image data V201 is discarded, the slice image data V201 is not displayed on the display image T201, and the slice image data V200 is displayed in the same manner as the display image T200.

  Processing after a decoding error occurs during decoding of the slice image data V201 differs depending on the size of the difference area in the subsequent frame. As illustrated in FIG. 13A, when the motion of the image is small and the temporary combined slice area is smaller than the predetermined size, the electronic device 100 uses the slice image data corresponding to the combined slice area as in the first embodiment. V202 is transmitted to the display device 200. As shown in the display image T202, the display device 200 displays the slice image data V202, whereby the afterimage of the slice image data V200 disappears.

  On the other hand, in FIG. 13B, as shown in the display image T212, the movement of the image is larger than that in FIG. 13A, and the size of the slice image data V212 corresponding to the temporary composite slice region is a predetermined value. Greater than size. In such a case, as shown in the display image T213, the electronic device 100 uses the area having a predetermined size including the error slice area as a composite slice area, and displays the slice image data V213 including the composite slice area having the predetermined size as a display device. 200.

  Thereafter, electronic device 100 includes a difference area in which a difference has occurred with the immediately preceding frame, which is included in the remaining inverted L-shaped slice area after removing slice image data V213 from slice image data V212. Specify a rectangular area. The electronic device 100 determines the identified rectangular area as a composite slice area necessary for returning to the latest image, and compares the size of the composite slice area with a predetermined size. When the synthesized slice area is equal to or smaller than the predetermined size, the electronic device 100 generates slice image data V214 based on the synthesized slice area. As shown in the display image T213 and the display image T214, the display device 200 displays the slice image data V214 after displaying the slice image data V213, thereby eliminating the image display delay.

  As described above, when the display system 1 according to the second embodiment transmits slice image data for recovery from a decoding error from the electronic device 100 to the display device 200, the size of the slice image data is set to a predetermined size or less. Restrict. Therefore, the display system 1 can reduce image quality deterioration due to compression encoding even when displaying a fast moving image.

[Embodiment 3]
FIG. 14 is a diagram for explaining the configuration of the electronic apparatus 300 according to the third embodiment. The electronic device 100 according to the first embodiment transmits slice image data including an error slice area when a decoding error occurs during decoding of slice image data. On the other hand, the electronic device 300 does not perform the process for the retransmission request for recovery from the decoding error when all the error slice areas are updated in a predetermined number of frames to be reproduced after the decoding error occurs. This is different from the electronic device 100 in that respect. Hereinafter, differences from the first embodiment will be described.

  In addition to the configuration of the electronic device 100, the electronic device 300 includes a first memory 310 that temporarily stores video data and a second memory 311 that temporarily stores difference information. The storage device 301, the encoding unit 305, the transmission unit 306, the reception unit 307, the operation unit 308, and the control unit 309 are the storage device 101, the encoding unit 105, the transmission unit 106, the reception unit 107, the operation unit 108, and the control unit, respectively. 109 has the same function.

  Similar to the difference extraction unit 102, the difference extraction unit 302 reads out video data in units of frames from the storage device 301 and extracts differences between adjacent frames. The difference extraction unit 302 sequentially outputs the frames read from the storage device 301 to the first memory 310. Further, the difference extraction unit 302 pre-reads a predetermined number of frames immediately after a frame to be output, extracts in advance difference information corresponding to the predetermined number of frames, and outputs the difference information to the second memory 311.

The first memory 310 stores image data of a predetermined number or more frames output from the difference extraction unit 302. Similar to the storage device 301, the first memory 310 is a hard disk device, a semiconductor memory, or the like.
The second memory 311 stores difference information corresponding to a predetermined number of frames output from the difference extraction unit 302. Similar to the storage device 301, the second memory 311 is a hard disk device, a semiconductor memory, or the like.

  The area determination unit 303 converts the difference information corresponding to the predetermined number of frames stored in the second memory 311 and information indicating the error slice area included in the specific information in the retransmission request acquired from the reception unit 307. Based on this, the final slice area is determined. For example, the region determination unit 303 includes all error slice regions in a region in which a plurality of slice regions corresponding to a predetermined number of frames scheduled to be transmitted from the transmission unit 306 are received after the reception unit 307 receives a retransmission request. It is determined whether or not it is included. The region determination unit 303 notifies the slice image data generation unit 304 of slice region information for specifying the determined slice region.

  The difference between the area determination unit 303 and the area determination unit 103 is that all error slice areas are included in an area obtained by combining a plurality of difference areas corresponding to image data of a plurality of frames (hereinafter referred to as a combined difference area). It is a point to determine whether or not. Here, the composite difference area is an area including all the pixels included in any of the plurality of difference areas. The combined difference area is, for example, a rectangular area that includes all pixels included in any of the plurality of difference areas.

  When at least a part of the error slice region is not included in the composite difference region, the region determination unit 303 determines a composite slice region including the error slice region and the difference region as a slice region cut out from the frame. If all error slice areas are included in the combined difference area, the area determining unit 303 does not determine the combined slice area as a slice area cut out from the frame. When transmitting the first frame of the video data to the display device 200, the region determining unit 303 determines all the regions of the first frame of the video data as slice regions.

  The slice image data generation unit 304 generates image data in the slice region from the image data of the frame input from the first memory 310 based on the slice region information input from the region determination unit 303.

  FIG. 15 is a flowchart for explaining processing for specifying a composite difference area based on a predetermined number of frames immediately after a frame to be output. The difference extraction unit 302 reads a predetermined number of frames immediately after the frame scheduled to be output from the transmission unit 306 from the storage device 301 in advance, and extracts a difference region determined based on the difference between adjacent frames. (S300). Then, the difference extraction unit 302 outputs difference information for specifying the extracted difference area to the second memory 311.

  Further, the difference extraction unit 302 outputs the frame from which the difference is extracted to the first memory 310 (S301). Thereafter, the difference extraction unit 302 waits until a frame is output from the transmission unit 306 (S302). After the frame is output in S302, the process returns to S300 and continues the process. When the difference extraction unit 302 executes the operations from S300 to S302, difference information between a predetermined number of frames immediately after the frame from which the slice image data is output is stored in the second memory 311.

  FIG. 16 is a flowchart for explaining a decoding error return process in the third embodiment. S400 to S403 in FIG. 16 are the same processes as S100 to S103 in FIG. S407 and S408 are the same processes as S105 and S106 in FIG. Here, the processing after S404 will be described.

  The area determining unit 303 acquires difference information corresponding to a predetermined number of frames from the next frame to be transferred from the second memory 311 (S404). After that, the area determination unit 303 combines all the error slice areas indicated by the specific information included in the retransmission request acquired in S403, by combining the difference areas between the predetermined number of frames acquired in S404. Compare whether or not (S405). Based on the comparison result, the region determination unit 303 determines whether or not the error slice region is updated by a predetermined number of subsequent frames (S406).

  Here, when all of the error slice areas are not included in the area obtained by combining the predetermined number of difference areas, the area determining unit 303 performs the same processing as S105 of FIG. 9 (S407). On the other hand, when all of the error slice areas are included in the area obtained by combining the predetermined number of difference areas, the area determining unit 303 determines the difference area of the next frame to be transferred as a combined slice area as it is (S409). ).

  As described above, in the display system 1 according to the third embodiment, when a decoding error occurs during decoding of slice image data, the error slice region is determined by a predetermined number of frames to be reproduced after the decoding error occurs. It is determined whether or not it is updated. Then, when the error slice area is updated with a predetermined number of frames, electronic device 100 does not perform a process for a retransmission request for decoding error recovery. In addition, when the error slice area is not updated with a predetermined number of frames, the electronic device 100 performs the same processing as in the first embodiment. Therefore, compared with the first embodiment, it is possible to reduce image quality deterioration when decoding error is restored. The third embodiment is effective when playing back video data that has already been recorded.

[Embodiment 4]
FIG. 17 is a diagram for explaining the configuration of the display device 400 according to the fourth embodiment. The display device 200 according to the first embodiment transmits a retransmission request to the electronic device 100 when a decoding error occurs during decoding of slice image data. On the other hand, the display device 400 does not transmit a retransmission request to the electronic device 100 when all error slice areas are updated in a predetermined number of frames to be reproduced after a decoding error occurs. Different from 200. Hereinafter, differences from the first embodiment will be described.

  The display device 400 includes an error area monitoring unit 408 in addition to the configuration of the display device 200. The reception unit 401, the image composition unit 403, the display unit 404, the operation unit 406, and the control unit 407 have functions equivalent to the reception unit 201, the image composition unit 203, the display unit 204, the operation unit 206, and the control unit 207, respectively.

  When the slice image data input from the reception unit 401 is compression-encoded, the decoding unit 402 decodes the compression-encoded slice image data. The decoding unit 402 outputs the decoded slice image data to the image composition unit 403. Further, the decoding unit 402 notifies the error region monitoring unit 408 of information indicating the slice region of the decoded slice image data. The decoding unit 402 discards the slice image data in which the decoding error has occurred and decodes the decoding error when a decoding error due to inability to decode occurs during decoding and the decoding process cannot be continued. The error area monitoring unit 408 is notified of information indicating the occurrence of the error.

  The error region monitoring unit 408 acquires slice region information indicating the slice region of the slice image data decoded by the decoding unit 402 based on the specific information transmitted along with the slice image data. When a decoding error occurs during decoding in the decoding unit 402, the error area monitoring unit 408 receives information indicating that a decoding error has occurred. After receiving the information indicating the occurrence of the decoding error, the error area monitoring unit 408 monitors the slice area information of a predetermined number of frames.

  For example, the error region monitoring unit 408 includes an error slice region that is a slice region of slice image data in which a decoding error has occurred in a region obtained by combining a plurality of slice regions corresponding to a predetermined number of frames. Determine. The error region monitoring unit 408 notifies the transmission unit 405 of information indicating the occurrence of a decoding error when the error slice region is not included in a region obtained by combining a plurality of slice regions corresponding to a predetermined number of frames.

  When the transmission unit 405 receives information indicating the occurrence of a decoding error from the error region monitoring unit 408, the transmission unit 405 sends a retransmission request for the slice image data in which the decoding error has occurred via the AUX channel line in the cable 150 to the electronic device 100. To output. For example, the transmission unit 405 issues a retransmission request when all of the error slice areas are not included in the plurality of slice areas corresponding to the predetermined number of slice image data transmitted after the slice image data in which the decoding error has occurred. Send. The transmission unit 405 does not transmit a retransmission request when all of the error slice areas are included in the plurality of slice areas.

FIG. 18 is a flowchart for explaining decoding error recovery processing in the display device 400.
When the decoding unit 402 of the display device 400 detects that a decoding error has occurred due to inability to decode during decoding, the decoding unit 402 discards the slice image data being decoded (S500). Thereafter, the decoding unit 402 determines whether the slice image data in which the decoding error has occurred includes image data for one frame (S501).

  When the slice image data in which the decoding error has occurred includes image data for one frame (Yes in S501), the decoding unit 402 requests retransmission of the image data for one frame via the transmission unit 405. When the slice image data in which the decoding error has occurred does not include image data for one frame (No in S501), the decoding unit 402 receives the specific information 591 and information indicating that the decoding error has been detected. The error area monitoring unit 408 is notified. In this case, the decoding unit 402 notifies the error region monitoring unit 408 of slice region information included in the specific information of the slice image data in which a decoding error has occurred. Thereafter, the decoding unit 402 receives the slice image data of the subsequent frame and continues decoding (S502).

  When the error region monitoring unit 408 receives information indicating that a decoding error has been detected from the decoding unit 402, the error region monitoring unit 408 thereafter receives slice region information of the subsequent frame decoded by the decoding unit 402. The error area monitoring unit 408 identifies an error slice area based on the slice area information included in the identification information of the frame in which the decoding error has occurred. The error area monitoring unit 408 compares the identified error slice area with a plurality of slice areas of a predetermined number of subsequent frames (S503).

  When all of the error slice areas of the slice image data in which the decoding error has occurred are included in the combined area obtained by combining the plurality of slice areas of the subsequent predetermined number of frames (Yes in S504), the error area monitoring unit In step 408, the processing ends without doing anything. In this case, the transmission unit 405 does not transmit a retransmission request to the electronic device 100.

  In the case of No in S504, the error region monitoring unit 408 determines whether slice region information of a predetermined number of frames has been received from the decoding unit 402 after the decoding error has occurred (S505). If the error area monitoring unit 408 has not received slice area information of a predetermined number of frames, the process returns to S502 and performs processing.

  When the error region monitoring unit 408 receives the slice region information of a predetermined number of frames, the error region monitoring unit 408 notifies the transmission unit 405 of information indicating the occurrence of the decoding error to the transmission unit 205 and the frame of the frame where the decoding error has occurred. Notify specific information. When receiving the information indicating the occurrence of the decoding error and the specific information, the transmission unit 205 transmits a retransmission request including information on the slice area of the slice image data in which the decoding error has occurred to the electronic device 100. (S506). Thereafter, the processing on the electronic device 100 side is the same as S103 to S106 in FIG.

  FIG. 19 is a diagram for explaining an example of display image transition in the display device 400. It is assumed that a decoding error has occurred during decoding of the slice image data V401 to be displayed on the display image T401. The slice data V402 displayed on the subsequent display image T402 does not include the slice area of the slice image data V401. However, after that, in the display image T403a shown in FIG. 19A, the slice area of the slice image data V403a includes the slice area of the slice image data V401 due to the appearance of a new object.

  As described above, in FIG. 19A, the slice area of the slice image data V401 in which the decoding error has occurred is included in the slice image data V403a in the predetermined number of subsequent frames. The retransmission request is not transmitted to the electronic device 100. On the other hand, in the slice area of the slice image data V403b shown in the display image T403b of FIG. 19B, the slice area of the slice image data V401 is combined with the area obtained by combining the slice areas of the slice image data in the predetermined number of subsequent frames. Is not included. Therefore, the display device 400 transmits a retransmission request to the electronic device 100.

  As described above, when a decoding error occurs during decoding of slice image data, the display device 400 according to the fourth embodiment monitors a predetermined number of frames received and decoded thereafter. When the slice area of the slice image data in which the decoding error has occurred is updated with a predetermined number of frames, the display device 400 does not transmit a retransmission request for returning the decoding error to the electronic device 100. Further, the display device 400 transmits a retransmission request to the electronic apparatus 100 as in the first embodiment when at least a part of the slice area of the slice image data in which the decoding error has occurred is not updated. Therefore, the display device 400 can reduce image quality degradation when decoding error is restored, as in the third embodiment.

[Embodiment 5]
In the first embodiment, when it is detected that a decoding error has occurred during decoding, the electronic device 100 specifies an error slice area based on information included in the retransmission request, and includes the error slice area The slice image data was transmitted to the display device 200. On the other hand, the electronic device in the fifth embodiment has the same configuration as the electronic device 300, and when the electronic device 300 cannot specify the error slice region, the entire region of the frame in which the decoding error has occurred. Is different in that it is retransmitted.

  For example, the region determination unit 303 determines all regions of a frame in which a decoding error has occurred as slice regions to be cut out from a new frame. The electronic device 300 according to the fifth embodiment generates a divided region by dividing one frame, and among the plurality of divided regions, displays a divided region including slice regions of a predetermined number of frames transmitted so far, with priority. 200. Electronic device 300 determines a divided area to be preferentially transmitted based on a plurality of difference areas corresponding to a predetermined number of frames immediately before a frame to be output. The process of specifying a plurality of difference areas is the same as the process described with reference to FIG. 15 in the third embodiment.

FIG. 20 is a flowchart for explaining a decoding error return process in the fifth embodiment.
First, the operation (S600 to S604) of the display device 200 will be described. When the decoding unit 202 of the display device 200 detects that a decoding error due to the inability to decode occurs during decoding of the slice image data, the decoding unit 202 discards the slice image data being decoded (S600). Thereafter, the decoding unit 202 determines whether the slice image data in which the decoding error has occurred includes image data for one frame (S601).

  When the slice image data in which a decoding error has occurred includes image data for one frame (Yes in S601), the decoding unit 202 requests retransmission of the image data for one frame via the transmission unit 205. When the slice image data in which a decoding error has occurred does not include image data for one frame (No in S601), the decoding unit 202 determines whether or not the slice area of the slice image data can be specified ( S602). The decoding unit 202 determines that the slice area cannot be specified when the specifying information 591 shown in FIGS. 7 and 8 cannot be acquired. In S602, the decoding unit 202 determines that the slice area can be specified when the specifying information 591 can be acquired.

  If the decoding unit 202 determines in S602 that the slice area can be specified, the decoding unit 202 notifies the transmission unit 205 of information indicating the occurrence of a decoding error and also notifies the corresponding frame specifying information 591. . When receiving the information indicating the occurrence of the decoding error and the specific information 591, the transmitting unit 205 sends the specific information 591 for specifying the slice area of the slice image data in which the decoding error has occurred to the electronic device 100. The included retransmission request is transmitted (S603).

  If the decoding unit 202 determines in S602 that the slice area cannot be specified, the decoding unit 202 notifies the transmission unit 205 of information indicating the occurrence of a decoding error, and the identification information 591 of the corresponding frame is “unknown”. ”Or“ None ”. When receiving the information indicating the occurrence of the decoding error and the specifying information 591, the transmitting unit 205 sends the specifying information 591 for specifying the slice area in the slice image data in which the decoding error has occurred to the electronic device 100. A retransmission request not included is transmitted (S604).

  Next, the operation (S605 to S612) of the electronic device 300 will be described. When receiving a retransmission request from the transmission unit 205, the reception unit 307 of the electronic device 300 confirms whether or not the retransmission request includes specific information 591 for specifying an error slice region, and determines the result as a region determination. The data is output to the unit 303 (S606). If the retransmission request includes the specific information 591, the area determination unit 303 acquires the difference information of the next frame to be transferred from the difference extraction unit 302 (S 607). The region determination unit 303 determines a region including the error slice region specified by the specification information 591 acquired in S606 and the difference region corresponding to the difference information acquired in S607 as a new composite slice region (S608). ).

  The slice image data generation unit 304 generates image data in the composite slice region from the image data of the frame input from the difference extraction unit 302 based on the composite slice region information input from the region determination unit 303. The generated slice image data is encoded by the encoding unit 305 and transmitted to the display device 200 via the transmission unit 306 (S609).

  In S606, when the retransmission request does not include the specific information 591 and the area determination unit 303 cannot specify the error slice area, the area determination unit 303 receives the frame of the already transmitted frame from the difference extraction unit 302. A predetermined number of difference information is acquired (S610). Here, the predetermined number is a number necessary for roughly specifying a slice region corresponding to slice image data in which a decoding error has occurred. For example, the predetermined number is the number of slice image data output from the electronic device 300 within a period required from when the electronic device 300 transmits slice image data to when a retransmission request for the slice image data is received. .

  Based on the plurality of pieces of difference information acquired from the difference extraction unit 302, the region determination unit 303 specifies a difference region corresponding to a predetermined number of frames before the reception unit 307 receives the retransmission request. The area determining unit 303 divides the frame into predetermined divided areas, and determines the priority of the plurality of divided areas in descending order of the proportion occupied by the identified difference areas (S611).

  FIG. 21 is a diagram for explaining an example of divided areas. FIG. 21 shows an example in which the frame is divided into four regions in the Y-axis direction. For example, when the ratio of the difference areas is large in the order of the divided areas R1, R2, R3, and R4, the area determining unit 303 assumes that the priority is higher in the order of the divided areas R1, R2, R3, and R4. Thereafter, the slice image data generation unit 304 divides the input frame based on the frame input from the difference extraction unit 302 and the information related to the divided region input from the region determination unit 303. The divided frames are encoded by the encoding unit 305 in order of priority, and are sequentially transmitted to the display device 200 via the transmission unit 306 (S612).

  FIG. 22 is a diagram for explaining an example of transition of a display image in the fifth embodiment. It is assumed that a decoding error has occurred during decoding of the slice image data V501 to be displayed on the display image T501. Thereafter, it is assumed that the slice image data included in the region P indicated by the solid line of the display image T502 is transmitted before the electronic device 300 receives the retransmission request.

  From display image T503 to display image T506, divided regions R1, R2, R3, and R4 are shown, respectively. The divided regions R1 and R2 having a relatively large area including the region P have higher priority than the divided region R3 having a relatively small area including the region P. The divided region R4 that does not include the region P has the lowest priority. Therefore, when receiving a retransmission request, electronic device 300 first transmits slice image data in which divided region R1 is a slice region to display device 200. Subsequently, the electronic device 300 sequentially transmits slice image data corresponding to the divided regions R2, R3, and R4 to the display device 200.

  As described above, according to the fifth embodiment, even when the electronic apparatus 300 cannot identify a slice area where a decoding error has occurred during decoding of slice image data, The divided frames can be transmitted in a predetermined order. By doing so, it is possible to update the image data of the area where the decoding error has occurred in a state where the deterioration of the image quality is reduced without increasing the compression rate. In addition, the electronic device 300 can restore the part where the decoding error has occurred earlier by giving priority to the divided areas.

[Embodiment 6]
The various functions, processes, and methods described in the first to fifth embodiments can be realized by a personal computer, a microcomputer, a CPU, or the like using a program. Hereinafter, in the sixth embodiment, a personal computer, a microcomputer, a CPU, and the like are referred to as “computer X”. In the sixth embodiment, a program for controlling the computer X and for realizing the various functions, processes, and methods described in the first to fifth embodiments is referred to as “program Y”.
The various functions, processes, and methods described in the first to fifth embodiments are realized by the computer X executing the program Y. In this case, the program Y is supplied to the computer X via a computer-readable storage medium. The computer-readable storage medium according to the sixth embodiment includes at least one of a hard disk device, a magnetic storage device, an optical storage device, a magneto-optical storage device, a memory card, a ROM, and a RAM. The computer-readable storage medium in the sixth embodiment is a non-transitory storage medium.

DESCRIPTION OF SYMBOLS 100 Electronic device 102 Difference extraction part 104 Slice image data generation part 106 Transmission part 107 Reception part

Claims (7)

Generating means for generating slice image data that is image data in the first slice region determined based on the difference between the image data of a plurality of frames;
Encoding means for compressing and encoding the slice image data;
Transmitting means for transmitting the compression-encoded slice image data to a display device;
Receiving means for receiving, from the display device, a retransmission request including information indicating the first slice area when a decoding error occurs in the slice image data;
When the retransmission request is received, a second slice area including a region corresponding to the first slice region in a second frame after the first frame corresponding to the first slice region An electronic apparatus comprising: control means for controlling image data to be transmitted to the display device.   The electronic apparatus according to claim 1, further comprising: an area determining unit that determines the second slice area based on the difference area determined based on the difference and the first slice area. When the area including the difference area and the first slice area is not larger than a predetermined size, the area determination unit determines that the area including the difference area and the first slice area is the second slice. Decide on the area,
When the area including the difference area and the first slice area is larger than the predetermined size, the area determining unit determines the area of the predetermined size including the first slice area as the second slice. The electronic device according to claim 2, wherein the electronic device is determined as a region.   When the information indicating the first slice area is not included in the retransmission request, the area determination unit determines all areas of the second frame as the second slice area. The electronic device according to claim 2.   When the retransmission request does not include information indicating the first slice area, the control unit transmits a plurality of pieces of image data corresponding to a plurality of divided areas of the second frame in a predetermined order. The electronic device according to claim 4, wherein the electronic device is controlled as follows. Computer
Generating means for generating slice image data that is image data in the first slice region determined based on the difference between the image data of a plurality of frames;
Encoding means for compressing and encoding the slice image data;
Transmitting means for transmitting the compression-encoded slice image data to a display device;
Receiving means for receiving, from the display device, a retransmission request including information indicating the first slice area when a decoding error occurs in the slice image data;
When the retransmission request is received, a second slice area including a region corresponding to the first slice region in a second frame after the first frame corresponding to the first slice region A program for functioning as control means for controlling image data to be transmitted to the display device. A generation step of generating slice image data that is image data in the first slice region determined based on the difference between the image data of a plurality of frames;
An encoding step of compressing and encoding the slice image data;
A transmission step of transmitting the compression-encoded slice image data to a display device;
A reception step of receiving, from the display device, a retransmission request including information indicating the first slice area when a decoding error occurs in the slice image data;
When the retransmission request is received, a second slice area including a region corresponding to the first slice region in a second frame after the first frame corresponding to the first slice region And a control step of controlling the image data to be transmitted to the display device.