JP2002152679A - Signal reproducing method and signal reproducing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily confirm a video part with movement from recorded signals. SOLUTION: When P picture is detected in ST1, the signal quantity Kp of the P picture is calculated in ST2. When signal quantity Kp is larger than a first reference value Km in ST3, a system proceeds to ST4. In ST4, the start position of a reproduction is set based on the detected P picture. The start position is set to I picture so that a decoded signal is precisely decoded. When data on the I picture is discriminated to be detected, the reproduction is started in ST5. When signal quantity Kp is discriminated to be not more than a second reference value Kn in ST6, a reproduction is terminated in ST7 and the system returns to ST1. The video parts having movement with which the signal quantity of the P picture becomes large are sequentially retrieved and they can be outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a signal reproducing method and a signal reproducing apparatus. More specifically, the coded signal of the video content is read from the recording medium, the signal amount of the forward prediction coded image is determined, and the signal amount of the forward prediction coded image determined to be larger than the first reference value is determined. The reproduction process is performed by setting the start position of the reproduction process of the encoded signal on the basis of the coded signal. When the signal amount is determined to be equal to or less than the second reference value, the reproduction process is terminated and the next forward By discriminating the signal amount of the prediction coded image, only a moving image is reproduced.

[0002]

2. Description of the Related Art In recent years, surveillance cameras have been widely used for crime prevention and the like. When this surveillance camera is used, it is possible to not only monitor the video shot by the surveillance camera in real time, but also record the video shot by the surveillance camera on a video tape using a time-lapse video recorder or the like. Is being done. Therefore, even if monitoring is not performed in real time, when an abnormality such as a crime occurs, it is possible to investigate the cause of the abnormality by reproducing the video recorded on the video tape. I have.

[0003]

By the way, for example, when an employee takes a picture of a company after returning home and records it on a videotape using a surveillance camera, when an abnormality occurs, the videotape is reproduced to cause a problem. Survey is conducted. Here, when the time of occurrence of the abnormality is unknown, it is necessary to play back the unchanged video in order from the beginning and detect the image in which the abnormality has occurred. I can't confirm.

Accordingly, the present invention provides a signal reproducing method and a signal reproducing apparatus capable of easily and easily confirming a moving image from a recorded signal.

[0005]

According to the signal reproducing method of the present invention, coded signals of video contents are sequentially read from a recording medium, and a signal of a forward prediction coded image is detected from the coded signals. The signal amount of the forward prediction coded image is determined, and the start position of the reproduction processing of the coded signal is set based on the forward prediction coded image of the signal amount determined to be larger than the first reference value. Is what you do.

Further, the signal reproducing device reads out the encoded signal recorded in the data storage means, which records the encoded signal of the video content, and discriminates the signal amount of the forward prediction encoded image. And control means for controlling a reproduction process of the coded signal based on the determination result. The control means performs coding based on the forward prediction coded image of the signal amount determined to be larger than the first reference value. This is for setting the start position of the reproduction processing of the coded signal.

In the present invention, coded signals of video contents recorded in a data storage such as a hard disk are sequentially read to determine a signal amount of a forward prediction coded image. When it is determined that the value is larger than the value, the coded signal of the intra-coded image used when decoding the forward-predicted coded image, or the first intra-coded image after the forward-predicted coded image Is set at the start position of the reproduction process, and the encoded signal is decoded from this start position to output the video signal. When it is determined that the signal amount of the forward prediction coded image is equal to or smaller than the second reference value smaller than the first reference value during the reproduction process, the reproduction process is terminated.

[0008]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a configuration of a signal recording / reproducing apparatus 10 capable of recording a signal and reproducing the recorded signal.

The input switching section 11 selects one of a plurality of supplied contents based on a control signal SE from an operation control section 50 described later, and outputs a video signal SVin of the selected content to the video input processing section 12. And supplies the audio signal SAin to the A / D converter 13.

[0010] The video input processing section 12 generates digital luminance data Yin and color difference data Crin and Cbin from the supplied video signal SVin and supplies them to the video encoder 20 and the output switching section 31. The A / D converter 13 converts the analog audio signal SAin into digital audio data DAin and supplies the digital audio data DAin to the audio encoder 22 and the output switching unit 32.

In the video encoder 20, for example, an ISO
The encoding process defined as / IEC13818-2 is performed using the memory 21 connected to the video encoder 20. That is, the video input processing unit 1
2, the luminance data Yin and the color difference data Crin,
The Cbin is subjected to screen rearrangement, motion compensation prediction, and the like in units of pictures (I, P, B), and performs DCT coding and variable length coding to generate video coded data VBw.

In the video encoder 20, the encoding bit rate in the encoding process is set to a fixed bit rate (CB
R: Constant Bit Rate) or variable bit rate (VBR:
Variable Bit Rate).

In this fixed bit rate encoding process,
For example, code amounts are allocated to I, P, and B pictures, and the quantization scale code is dynamically changed by feedback control so that the code amount allocated to each picture matches the actual generated code amount. On the other hand, in the variable bit rate encoding process, the quantization scale code is adjusted according to the visual characteristics, and control is performed so that the average value of the bit rate becomes a desired value. In other words, in a portion where deterioration is conspicuous visually, the quantization scale code is adjusted so as to be finely quantized, and the code amount is increased.In a portion where deterioration is not conspicuous, the code amount is adjusted by coarsely quantizing the code. By reducing the bit rate, the bit rate is varied so that the average value is controlled to a desired bit rate. Therefore, with a variable bit rate, good image quality can be obtained even if the bit rate is low.

In the audio encoder 22, for example, I
An encoding process defined as SO / IEC11172 is performed. That is, the audio data DAin supplied from the A / D converter 13 is divided into sub-bands, quantized independently for each sub-band, and bit-compressed to generate encoded audio data ABw.

The coded video data VBw generated by the video encoder 20 and the coded audio data ABw generated by the audio encoder 22 are multiplexed by the multiplexing unit 23 into a single coded signal SSw. Thereafter, it is supplied to the data storage interface 40.

The data storage interface 40 converts the supplied encoded signal SSw into the data storage 4
Record in 1. The data storage 41 is configured using a recording medium that can be randomly accessed, for example, a magnetic disk, an optical disk, a semiconductor memory, or the like. Further, the data storage interface 40 reads the coded signal recorded in the data storage 41 and supplies the coded signal to the separation unit 24.

Here, the data storage interface 40 is constituted by using a plurality of banks of memories or a plurality of memories, and the data transfer rate in the data storage 41 is controlled by the coded signal SS from the multiplexing unit 23.
w is higher than the transmission speed of w, the supplied encoded signal SSw is temporarily stored in one bank, and
The stored recording coded signal SSw is recorded in the data storage 41 in the allocated processing period. Further, the stored encoded signal SSw is stored in the data storage 4
1, the encoded signal SSw supplied during the recording period
Is temporarily stored in a different bank. On the other hand, when reading the coded signal SSr recorded in the data storage 41, the coded signal SSw is read from the data storage 41.
In a processing period different from the processing period used when recording
A desired coded signal SSr is read from the data storage 41 and temporarily stored in a bank where no coded signal is stored. Further, the held encoded signal SS
r is sequentially supplied to the separation unit 24, and the encoded signal SSr read during the period in which the held encoded signal SSr is supplied to the separation unit 24 is temporarily stored in a different bank.

As described above, the supply of the coded signal SSw from the multiplexing section 23 to the data storage interface 40 and the separation of the separation section 2 from the data storage interface 40 are performed.
4 can be simultaneously supplied to the data storage interface 40 and the data storage 41, and the writing and reading of the encoded signal are performed at high speed individually, thereby recording and reproducing the content. Can be performed simultaneously.

The separating section 24 separates the coded video data VBr and the coded audio data ABr from the coded signal SSr supplied from the data storage interface 40, and outputs the coded video data VBr to the video decoder 25 and the operation control section. 50 and the audio coded data AB
r is supplied to the audio decoder 27.

The video decoder 25 decodes the coded video data VBr supplied from the separation unit 24 using the memory 26 connected to the video decoder 25. Luminance data Y obtained by decoding processing
The r and the color difference data Crr, Cbr are supplied to the output switching unit 31. When the video encoder 20 decodes the encoded video data for which the resolution sampling has been performed by 倍 times, the video encoder 20 performs upscaling to double the amount of data in the horizontal direction.

In the audio decoder 27, the separating unit 24
The decoding processing is performed on the encoded audio data ABr supplied from, and the obtained audio data DAr is supplied to the output switching unit 32.

In the output switching unit 31, when displaying an image based on the signal selected by the input switching unit 11 based on the control signal SE from the operation control unit 50, the luminance supplied from the video input processing unit 12 is displayed. Data Yin and color difference data C
rin and Cbin are selected and supplied to the video output processing unit 35 as output luminance data Yout and color difference data Crout and Cbout. When an image is displayed by reproducing an encoded signal recorded in the data storage 41, the luminance data Yr supplied from the video decoder 25 is displayed.
And the color difference data Crr and Cbr are selected and supplied to the video output processing unit 35 as output luminance data Yout and color difference data Crout and Cbout.

The output switching section 32 outputs an audio signal based on the signal selected by the input switching section 11 based on the control signal SE from the operation control section 50.
The audio data DAin supplied from 3 is selected and supplied to the D / A converter 36 as audio data DAout for output. When reproducing the encoded signal recorded in the data storage 41 and outputting the audio, the audio data DAr supplied from the audio decoder 27 is selected, and D / A is output as the audio data DAout for output. Converter 3
6

The video output processing unit 35 uses the supplied luminance data Yout and color difference data Crout and Cbout to output video signals corresponding to the display device 60 connected to the signal recording / reproducing device 10, for example, luminance data and color difference data. And performs a D / A conversion process and an encoding process, and adds a synchronization signal to generate and output an analog composite video signal SVout. The D / A converter 36 converts the supplied audio data DAout into an analog audio signal SAout and outputs it.

The data storage interface 40 is connected to a communication interface 42 such as IEEE1394, and outputs an encoded signal read from the data storage 41 to another device via the communication interface 42. Further, the encoded signal supplied from another device is recorded in the data storage 41.

An operation section 51 is connected to the operation control section 50. The operation section 51 generates a control signal SE based on an operation signal PS from the operation section 51 and supplies the control signal SE to each section. Is controlled to be performed by the signal recording / reproducing device 10. The operation control unit 50 is connected to a display unit 52.
The display state of the signal recording / reproducing apparatus 10 and various information are displayed by supplying the display drive signal HS to the CPU. Further, the operation control unit 50 determines the signal amount of the P picture which is a forward prediction coded image from the coded signal SSr read from the data storage 41, and based on the determination result, determines the amount Perform playback processing.

Next, the operation of reproducing the encoded signal recorded in the data storage 41 will be described with reference to the flowchart of FIG. First, in order to search for a portion where a movement has occurred and start a reproduction process, in step ST1,
The coded signal is read out from the data storage 41 in the time forward direction, and it is determined whether or not the data of the P picture has been detected.

Since the data transfer rate in the data storage 41 is higher than the transmission rate of the coded signal, for example, if the coded signal is read continuously from the data storage 41, Data VBr
Can be detected faster than in the case where an encoded signal is read from the data storage 41 in order to decode and output as a video signal.

The encoded video data VBr is shown in FIG.
Has a hierarchical structure as shown in FIG. 1, and includes a sequence layer, a GOP (Group Of Picture) layer, a picture layer, a slice layer, a macroblock layer, and a block layer from the top. The picture header at the head of this picture layer is shown in FIG.
As shown in the figure, a PSC (Picture S) indicating the start of the picture layer
tart Code), TR (Temporal
Reference), PCT (Picture Cod
ing Type) is provided.
When it is "1", it is an I picture, when it is "010", it is a P picture, and when it is "011", it is a B picture. Therefore, the picture header PCT
, It can be determined whether or not the data is P-picture data.

If it is determined in step ST1 that the data is P picture data, the process proceeds to step ST2. If it is not determined that the data is P picture data, the process returns to step ST1.

In step ST2, the signal amount Kp of the P picture is calculated. The signal amount Kp of the P picture is determined by the PCT after it is determined that the data is P picture data.
Next, the signal amount until the PSC is detected is set. Alternatively, when it is determined that the data is P-picture data so that the signal amount of the P-picture does not fluctuate due to extension data added after the PCT of the picture header, the start position of the slice layer is detected. Then, the signal amount from the start position of the slice layer until the next detection of the PSC can be used as the signal amount of the P picture. Here, at the head of the slice layer, S indicating the start of the slice layer is set.
An SC (Slice Start Code) is provided as a part of the slice information, and the SSC has a start code “0000”.
01 ”and a 1-byte slice vertical position code (01 to A
F), and by detecting this SSC,
The head position of the slice layer can be detected.

Next, in step ST3, it is determined whether or not the calculated signal amount Kp of the P picture is larger than a predetermined determination reference value Km. Here, when the signal amount Kp is not larger than the determination reference value Km, it is determined that there is no moving image, and the process returns to step ST1 to detect the next P picture. On the other hand, when the signal amount Kp of the P picture is larger than the determination reference value Km, it is determined that the image is a moving image, and the process proceeds to step ST4.

In step ST4, the signal amount Kp is set so that video coded data of a moving video can be correctly decoded.
Is an intra-coded image used when decoding a P-picture determined to be larger than the determination reference value Km, or a P-picture after a P-picture whose signal amount Kp is determined to be larger than the determination reference value Km. The first I picture is set as the start position of the reproduction processing, and it is determined whether or not the data of this I picture has been read. Here, if the I picture used when decoding the P picture is set as the start position of the reproduction processing, the P picture whose signal amount Kp is determined to be larger than the determination reference value Km can be displayed. Further, if the first I picture after the P picture is set as the start position of the reproduction processing, the signal read position can be read out by sequentially reading the encoded signal without returning the signal read position in the data storage 41. Can be at the starting position.

If it is determined in step ST4 that the data of the I picture has not been read, the process proceeds to step ST4.
Returning to step 3, when it is determined that the data of the I picture has been read, the process proceeds to step ST5. It should be noted that whether or not the data of the I picture has been read may be determined by determining whether or not the PCT of the above-mentioned picture layer is “001”.

In step ST5, the reproduction process is started from the set start position. That is, the video decoder 25
, The video encoded data VBr sequentially from the I picture
, And the video output processing unit 35 generates and outputs the video signal SVout. Further, during the reproduction process, the coded signal is read from the data storage 41 in accordance with the decoding process status of the coded video data VBr.

Next, when the moving picture ends, the reproduction process is terminated and the moving picture is searched again. Therefore, in step ST6, the signal amount Kp of the P picture is set to be equal to or less than the predetermined reference value Kn. It is determined whether or not there is. The discrimination reference value Kn is set to a value smaller than the discrimination reference value Km so that the switching operation has a hysteresis characteristic so that switching between the start and end of the reproduction process is not repeated in a short time.

If the signal amount Kp is larger than the determination reference value Kn in step ST6, it is determined that a moving image is continuing, and the process returns to step ST6. Signal amount Kp
Is less than or equal to the determination reference value Kn, it is determined that the moving image has ended, and the process proceeds to step ST7.

In step ST7, the reproduction process started in step ST5 is terminated, and the process returns to step ST1, in which the encoded signals are sequentially read from the data storage 41, and the next moving portion is searched at high speed.

As described above, the moving picture is searched at high speed based on the signal amount Kp of the P picture, and the signal amount Kp is searched.
Is larger than a predetermined determination reference value Km, the reproduction process is started assuming that a moving image has been recorded. When the signal amount Kp becomes equal to or less than a predetermined determination reference value Kn, the reproduction process is terminated assuming that the moving image has been terminated, and the next moving image can be searched at high speed. Is done. For this reason, only moving images are sequentially searched and displayed on the screen of the display device 60. Therefore, only by monitoring the screen of the display device 60, the moving images can be checked efficiently and easily. can do.

In the above-described embodiment, the reproduction process is started in step ST4 when the start position of the reproduction process is set. However, the display unit 52 indicates that the start position of the reproduction process is set. , And generates and outputs a video signal SVout indicating that the start position of the reproduction process is set, and performs the reproduction process from the start position set when the operation unit 51 is operated. good. In this case, even if the screen of the display device 60 is not constantly monitored,
By operating the operation unit 51 when it is indicated that the start position of the reproduction process has been set, it is possible to easily confirm a moving image.

[0041]

According to the present invention, the start position of the coded signal reproduction processing is set based on the forward prediction coded image of the signal amount determined to be larger than the first reference value. By performing the reproduction process from this start position, it is possible to easily and easily confirm a moving video portion from the encoded signal recorded on the recording medium.

If it is determined during the reproduction process that the signal amount of the forward prediction coded image is equal to or smaller than a second reference value smaller than the first reference value, the reproduction process is terminated.
Again, the signal amount of the forward prediction coded image is compared with the first reference value. For this reason, when there is no movement, a search is made for the next moving image portion, and only the moving image portion can be sequentially and easily confirmed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a signal recording / reproducing apparatus.

FIG. 2 is a flowchart showing a reproduction operation of an encoded signal.

FIG. 3 is a diagram showing a structure of video encoded data.

[Explanation of symbols]

 Reference Signs List 10 signal recording / reproducing device 11 input switching unit 12 video input processing unit 13 A / D conversion unit 20 video encoder 21, 26 memory 22 audio encoder 23 multiplexing unit 24 separation unit 25 video decoder 27 audio decoder 31, 32 output switching unit 35 Video output processing unit 36 D / A conversion unit 40 Data storage interface 41 Data storage 42 Communication interface 50 Operation control unit 51 Operation unit 52 Display unit 60 Display device

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoji Watanabe 1-2-1-11 Ikenohata, Taito-ku, Tokyo F-term in Iwa Corporation (reference) 5C053 FA12 FA23 GB37 HA29 KA05 KA25

Claims (4)

[Claims] 1. A coded signal of video content is sequentially read from a recording medium, and a signal of a forward prediction coded image is detected from the coded signal to determine a signal amount of the forward prediction coded image. A signal reproduction method comprising: setting a start position of reproduction processing of the encoded signal based on a forward prediction encoded image of the signal amount determined to be larger than a first reference value. 2. When the signal amount of the forward prediction coded image is determined to be equal to or smaller than a second reference value smaller than the first reference value during the reproduction processing, the reproduction processing is terminated. The signal amount of the forward prediction coded image and the first
2. The signal reproducing method according to claim 1, wherein comparison is made with a reference value. 3. A data storage means for recording an encoded signal of video content, and the encoded signal recorded in the data storage means is read to determine a signal amount of a forward prediction encoded image. Control means for controlling the reproduction process of the encoded signal based on the result, wherein the control means, based on the forward prediction encoded image of the signal amount determined to be larger than the first reference value, A signal reproducing apparatus for setting a start position of a reproduction process of the encoded signal. 4. The control means, when it is determined that the signal amount of the forward prediction coded image is equal to or smaller than a second reference value smaller than the first reference value during the reproduction processing, 4. The signal reproducing apparatus according to claim 3, wherein the reproduction processing is completed, and the signal amount of the forward prediction coded image is compared with the first reference value.