CN104967803B - A kind of video recording method and device - Google Patents

Abstract

The embodiment of the present invention discloses a video recording method and device, wherein the video recording method includes: when recording a video, track the target tracking object in the selected video, and determine the target tracking object based on the tracking result The moving speed of the object; adjust the current video recording frame rate according to the moving speed of the target tracking object. By adopting the technical solution provided by the embodiments of the present invention, it is possible to accurately adjust the current video shooting speed when recording fast moving objects, so that the video effect of the shooting is better, and the user experience of shooting video is improved.

Description

A video recording method and device

technical field

Embodiments of the present invention relate to the field of video recording, and in particular, to a video recording method and device.

Background technique

With the rapid development of smart terminal technology, smart terminal products can meet more and more functions of users. At the same time, the user's demand for multiple functions is becoming more and more urgent. For example, because smart terminal products are mobile and easy to carry, more and more users choose to take pictures and record videos.

When people take pictures or videos of moving people, animals or objects (collectively referred to as "subjects"), they generally use tracking algorithms to track the subject, display the position of the tracked object with relevant pictures, and focus on the tracked subject Operation, so that the subject is always in a relatively clear scene, but for the subject in a fast-moving state, the performance of the recorded video will still be relatively blurred, which will affect the user experience of shooting video.

Contents of the invention

In view of this, an embodiment of the present invention proposes a video recording method and device, so as to improve the video recording effect of tracking objects during the video recording process.

On the one hand, an embodiment of the present invention provides a video recording method, the method comprising:

When recording the video, track the target tracking object in the selected video, and determine the moving speed of the target tracking object based on the tracking result;

Adjust the current video recording frame rate according to the moving speed of the target tracking object.

On the other hand, an embodiment of the present invention also provides a video recording device, the device comprising:

The moving speed acquisition module is used to receive the selection of the target tracking object when recording the video, and obtain the moving speed of the target tracking object;

The image frame number adjustment module is used to adjust the number of image frames captured per second for the current video recording according to the moving speed of the target tracking object.

The method and device provided by the embodiments of the present invention receive the selection of the target tracking object when recording a video, obtain the moving speed of the target tracking object, and adjust the current video recording every time according to the moving speed of the target tracking object. The number of image frames captured per second. It is realized that the current video shooting speed can be accurately adjusted when recording fast moving objects, so that the video effect of the shooting is better, and the user experience of shooting video is improved.

Description of drawings

Other characteristics, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings:

Fig. 1 is a flow chart of the video recording method provided by the first embodiment of the present invention;

Fig. 2 is a flow chart of the video recording method provided by the second embodiment of the present invention;

Fig. 3 is a flow chart of the video recording method provided by the third embodiment of the present invention;

Fig. 4 is a flow chart of the video recording method provided by the fourth embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a video recording device provided by a fifth embodiment of the present invention.

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention. In addition, it should be noted that, for the convenience of description, only parts related to the present invention are shown in the drawings but not all content.

Figure 1 shows a first embodiment of the invention.

Fig. 1 is a schematic flow chart of a video recording method provided by the first embodiment of the present invention. The method of this embodiment can be executed by a video recording device, which can be implemented by means of hardware and/or software, and can generally be integrated in the smart terminal.

Referring to Fig. 1, the described video recording method comprises:

Step S101, when recording a video, track the target tracking object in the selected video, and determine the moving speed of the target tracking object based on the tracking result.

When using the smart terminal to record video, the smart terminal selects the target tracking object by receiving the corresponding operation instructions from the user. For example, an operation of clicking an object displayed on the screen is received, and the clicked object is determined as a target tracking object. The user can select a target to track an object when the video starts to be recorded or during the recording process, or before the video starts to be recorded, by displaying a preset image frame on the screen, receiving the user's operation of moving or zooming in and out of the image frame, and determining the target object. The object in the above image frame is the target tracking object.

Object tracking is to determine the position of the target tracking object in each frame of the video. After selecting the target tracking object, it is necessary to detect the target tracking object. In this embodiment, since the smart terminal does not move or rotate during shooting, the captured background reference model is almost unchanged, and the background subtraction method can be used to detect the target tracking object. The background subtraction method is a method to detect the target tracking object by comparing the current frame in the image sequence with the background reference model. Using the background subtraction method to detect moving targets has the advantages of fast speed, accurate detection and easy implementation. By removing the background reference model in each frame of image, the position of the target tracking object in each frame of image can be accurately obtained.

Since the shooting interval of each frame of images is a certain value, the moving speed of the target tracking object is calculated by calculating the position change of the target tracking object in different frame images and the time interval of the different frame images.

Step S102, adjusting the current video recording frame rate according to the moving speed of the target tracking object.

According to the moving speed of the target tracking object acquired in step S101, the current video recording frame rate is adjusted according to the preset corresponding relationship between the moving speed of the target tracking object and the video recording frame rate. Video recording frame rate is the number of image frames captured in unit time. When the video recorded with high video recording frame rate is played, it can make the video more smooth and realistic. If the speed of the target tracking object is faster, then the current video recording frame rate needs to be increased, so that the recorded video will not cause the audience to feel that the image is stuck and not smooth due to the high-speed movement of the target tracking object when the recorded video is played.

The smart terminal can use hardware and/or software to adjust the current video recording frame rate. For example, for the Android system, the adjustment of the video recording frame rate can be realized by calling the setVideoFrameRate library function, or by modifying the parameters of the video recording device. For example, modify the hardware parameters of the camera to achieve.

In this embodiment, by receiving the selection of the target tracking object when recording a video, the moving speed of the target tracking object is obtained, and according to the moving speed of the target tracking object, the image frame captured per second of the current video recording is adjusted number. It is realized that the current video shooting speed can be accurately adjusted when recording fast moving objects, so that the video effect of the shooting is better, and the user experience of shooting video is improved.

Figure 2 shows a second embodiment of the invention.

Fig. 2 is a schematic flowchart of a video recording method provided by a second embodiment of the present invention. The video recording method is based on the first embodiment of the present invention, and further, adjusts the current video recording frame rate according to the moving speed of the target tracking object, and optimizes it to: when the moving speed of the target tracking object is greater than the expected When the normal moving speed is set, calculate the ratio of the moving speed of the target tracking object to the preset normal moving speed; calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate.

Referring to Fig. 2, the video recording method includes:

Step S201, when recording a video, track the target tracking object in the selected video, and determine the moving speed of the target tracking object based on the tracking result.

Step S202, when the moving speed of the target tracking object is greater than the preset normal moving speed, calculate the ratio of the moving speed of the target tracking object to the preset normal moving speed.

The moving speed of the target tracking object obtained in step S201 is compared with the normal moving speed. The normal moving speed is preset by the user or the system. When the moving speed of the target tracking object is greater than the preset normal moving speed, the ratio of the moving speed of the target tracking object to the preset normal moving speed is calculated. For example, the current moving speed of the target tracking object is 10 m/s, while the preset normal moving speed is 4 m/s, and the ratio of the moving speed of the target tracking object to the preset normal moving speed is 10/4 = 2.5.

Step S203, calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate.

According to the ratio calculated in step S202 and the preset normal video recording frame rate, the current video recording frame rate is calculated. The preset normal video recording frame rate is the number of image frames recorded per second by the camera device during normal recording. Generally, the normal video recording frame rate is between 17 frames per second and 30 frames per second, and the normal video recording frame rate can be preset by the user or the system. In this embodiment, the normal video recording frame rate is preferably 30 frames per second. According to the ratio and the preset normal video recording frame rate, the current video recording frame rate can be calculated, specifically: multiply the normal video recording frame rate by the ratio, and use the product result as the current video recording frame rate. For example, if the ratio is 1.5, the normal video recording frame rate is 30 frames/second, and the current video recording frame rate is 1.5×30 frames/second=45 frames/second. Adjust the current video recording frame rate according to the calculated recording frame rate.

In this embodiment, by adjusting the current video recording frame rate according to the moving speed of the target tracking object, it is optimized to: when the moving speed of the target tracking object is greater than the preset normal moving speed, calculate the The ratio of the moving speed to the preset normal moving speed; calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate. The adjusted current video recording frame rate can match the moving speed of the target tracking object, and the adjusted current video recording frame rate is prevented from being too large or too small. The recorded video of the target tracking object is closer to the real situation of the target tracking object moving, which improves the user experience of recording video.

Figure 3 shows a third embodiment of the invention.

Fig. 3 is a schematic flowchart of a video recording method provided by a third embodiment of the present invention. The video recording method is based on the first embodiment of the present invention, and further, adjusts the current video recording frame rate according to the moving speed of the target tracking object, and optimizes it to: when the moving speed of the target tracking object is less than the preset When the normal moving speed is set, the image frames captured by the currently recorded video will be dropped according to the preset rules.

Referring to Fig. 3, the video recording method includes:

Step S301, when recording a video, track the target tracking object in the selected video, and determine the moving speed of the target tracking object based on the tracking result.

Step S302 , when the moving speed of the target tracking object is lower than the preset normal moving speed, the image frames captured by the currently recorded video are subjected to frame dropping processing according to preset rules.

The movement of the target tracking object can be high-speed or low-speed. For the recording of low-speed target tracking objects, if the normal video recording frame rate is still used for recording without any processing, the recorded video will make the user feel that the video playback effect is not smooth when it is played. Therefore, it is necessary to process the video recorded at the normal video recording frame rate.

The moving speed of the target tracking object obtained in step S301 is compared with the normal moving speed, and the normal moving speed is preset by the user or the system. When the moving speed of the target tracking object is lower than the preset normal moving speed, the image frame captured by the currently recorded video is processed according to the preset rules, specifically: calculating the moving speed of the target tracking object and the preset The ratio of the normal moving speed; according to the ratio and the normal number of frames per second to determine the number of reserved frames per second; and according to the number of reserved frames per second and the normal number of frames per second Grouping, discarding frame images with the same order in each group.

For example, the moving speed of the target tracking object is 2 m/s, the preset normal moving speed is 4 m/s, and the ratio of the moving speed of the target tracking object to the preset normal moving speed is 1/2. Normally, the number of frames obtained per second is 30 frames, so the number of frames retained per second is 30×1/2=15 frames, which also means that the number of frames discarded per second is 30-15=15 frames. The 30 frames of images normally acquired per second are divided into 15 groups, and the first frame of images in each group or the second frame of images in each group are discarded.

In this embodiment, by adjusting the frame rate of the current video recording according to the moving speed of the target tracking object, it is optimized to: when the moving speed of the target tracking object is lower than the preset normal moving speed, capture the currently recorded video The frame of the image is dropped according to the preset rules. When the target tracking object is in a slow motion state, the number of image frames captured by the currently recorded video is adjusted so that the frame rate of the recorded video is consistent with the moving speed of the target tracking object, which improves the user experience of recording video.

Fig. 4 shows a fourth embodiment of the invention.

Fig. 4 is a schematic flowchart of a video recording method provided by a fourth embodiment of the present invention. The video recording method is based on the first embodiment of the present invention. Further, before the target tracking object in the selected video is tracked, and the moving speed of the target tracking object is determined based on the tracking result, the following steps are added: It is detected that the preset object tracking start event is triggered.

Referring to Figure 4, the video recording method includes:

In step S401, it is detected that a preset object tracking start event is triggered.

When the user is recording a video, if the target tracking object is found to be in a fast or slow motion state, the user can enable the object tracking operation on the smart terminal.

Therefore, in this embodiment, the object tracking start event is monitored in real time to determine whether the object tracking start event is acquired. The object tracking start trigger event can be preset by the system or the user, and can be a setting trigger operation on the main touch screen of the smart terminal, or a trigger operation on one or more physical buttons on the terminal. Exemplarily, the real-time monitoring of the object tracking start event may specifically be: real-time monitoring whether there is a sliding operation on the recording video interface, and if so, it is detected that the preset object tracking start event is triggered.

Step S402, when recording the video, track the target tracking object in the selected video, and determine the moving speed of the target tracking object based on the tracking result.

Step S403, adjusting the current video recording frame rate according to the moving speed of the target tracking object.

In this embodiment, before the target tracking object in the selected video is tracked and the moving speed of the target tracking object is determined based on the tracking result, the following step is added: detecting that a preset object tracking start event is triggered. Enable users to choose whether to track objects according to the motion state of objects when recording videos.

On the basis of the above technical solution, in this embodiment, after the above step S403 "Adjust the current video recording frame rate according to the moving speed of the target tracking object", the following steps can also be added: the preset object is detected After the tracking off event is triggered, adjust the current video recording frame rate to the preset normal video recording frame rate.

When recording a video, the user can cancel the tracking of the target tracking object as needed, and can perform an object tracking shutdown operation on the smart terminal. The event of enabling and disabling object tracking may be preset by the system or the user. Exemplarily, the real-time monitoring of the object tracking off event may be specifically: monitoring in real time whether there is a double-click operation on the recording video interface, and if so, detecting that the preset object tracking off event is triggered. After detecting that the preset object tracking off event is triggered, since the current video recording frame rate may be the adjusted video recording frame rate, the current video recording frame rate needs to be adjusted to the normal video recording frame rate. For example, after detecting that the preset object tracking off event is triggered, the current video recording frame rate is 45 frames per second, and the current video recording frame rate is adjusted from 45 frames per second to the normal video recording frame rate of 30 frames per second.

Fig. 5 shows a fifth embodiment of the present invention.

Fig. 5 is a structural diagram of a video recording device provided by a fifth embodiment of the present invention. Referring to FIG. 5 , the video recording device includes: a moving speed determining unit 510 and a frame rate adjusting unit 520 .

Wherein, the moving speed determining unit 510 is configured to track the target tracking object in the selected video when recording the video, and determine the moving speed of the target tracking object based on the tracking result;

The frame rate adjustment unit 520 is configured to adjust the current video recording frame rate according to the moving speed of the target tracking object.

The video recording device provided in this embodiment obtains the moving speed of the target tracking object by receiving the selection of the target tracking object when recording a video, and adjusts the current video recording per second according to the moving speed of the target tracking object. The number of captured image frames. It is realized that the current video shooting speed can be accurately adjusted when recording fast moving objects, so that the video effect of the shooting is better, and the user experience of shooting video is improved.

Further, the frame rate adjustment unit 520 includes: a ratio calculation subunit 521 and a recording frame rate adjustment subunit 522

Wherein, the ratio calculating subunit 521 is configured to calculate the ratio of the moving speed of the target tracking object to the preset normal moving speed when the moving speed of the target tracking object is greater than the preset normal moving speed;

The recording frame rate adjustment subunit 522 is configured to calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate.

Further, the frame rate adjustment unit 520 includes: a frame loss processing subunit 523 .

Wherein, the frame dropping processing subunit 523 is configured to perform frame dropping processing on the image frames captured by the currently recorded video according to preset rules when the moving speed of the target tracking object is lower than the preset normal moving speed .

Further, the device further includes: an event trigger monitoring unit 530 .

The event trigger monitoring unit 530 is configured to detect that a preset object tracking start event is triggered.

Furthermore, the device further includes: a normal frame rate adjustment unit 540 .

The normal frame rate adjustment unit 540 is configured to adjust the current video recording frame rate to a preset normal video recording frame rate after detecting that a preset object tracking off event is triggered.

The above-mentioned video recording device can execute the video recording method provided by the embodiment of the present invention, and has corresponding functional modules and beneficial effects for executing the method.

The serial numbers of the above embodiments of the present invention are for description only, and do not represent the advantages and disadvantages of the embodiments.

Those of ordinary skill in the art should understand that each module or each step of the present invention described above can be realized by a general-purpose computing device, and they can be concentrated on a single computing device, or distributed on a network formed by multiple computing devices. Optionally, they can be implemented with executable program codes of computer devices, so that they can be stored in storage devices and executed by computing devices, or they can be made into individual integrated circuit modules, or a plurality of modules in them Or the steps are fabricated into a single integrated circuit module to realize. As such, the present invention is not limited to any specific combination of hardware and software.

Each embodiment in this specification is described in a progressive manner, each embodiment focuses on the difference from other embodiments, and the same or similar parts between the various embodiments can be referred to each other.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims (4)

1. A video recording method, characterized in that it is applied to a scene where the smart terminal does not move or turn when shooting, and the method includes: When recording a video, by monitoring the sliding operation of the recording video interface in real time, it is detected that the preset object tracking start event is triggered; When using a smart terminal to record a video, the target tracking object is determined by receiving the user's operation instruction of clicking on the object on the video interface, or by displaying a preset image frame on the screen before the video starts recording, receiving the user's movement or zooming in and out The operation of the image frame determines that the object in the image frame is a target tracking object; The target tracking object in the selected video is tracked by the background difference method, and the moving speed of the target tracking object is determined based on the tracking result; According to the moving speed of the target tracking object, adjust the current video recording frame rate, including: When the moving speed of the target tracking object is greater than the preset normal moving speed, calculate the ratio of the moving speed of the target tracking object to the preset normal moving speed; By monitoring the double-click operation on the recording video interface in real time, after detecting that the preset object tracking off event is triggered, adjust the current video recording frame rate to the preset normal video recording frame rate; Calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate, wherein the video recording frame rate is the number of image frames recorded by the smart terminal per unit time. 2. The method according to claim 1, wherein adjusting the current video recording frame rate according to the moving speed of the target tracking object comprises: When the moving speed of the target tracking object is lower than the preset normal moving speed, the captured image frames of the currently recorded video are subjected to frame dropping processing according to preset rules. 3. A video recording device, characterized in that it is applied to a scene where the smart terminal does not move or rotate when shooting, and the device includes: The event trigger monitoring unit is used to detect that the preset object tracking start event is triggered by real-time monitoring the sliding operation of the recording video interface when recording the video; The moving speed determination unit is used to determine the target tracking object by receiving the user's operation instruction of clicking on the object on the video interface when using the smart terminal to record the video, or by displaying a preset image frame on the screen before the video recording starts, receiving The user moves or zooms in on the image frame to determine the object in the image frame as the target tracking object; the target tracking object in the selected video is tracked using the background difference method, and the target tracking is determined based on the tracking result the speed at which the object is moving; A frame rate adjustment unit, configured to adjust the current video recording frame rate according to the moving speed of the target tracking object, including: A ratio calculation subunit, used to calculate the ratio of the moving speed of the target tracking object to the preset normal moving speed when the moving speed of the target tracking object is greater than the preset normal moving speed; The normal frame rate adjustment unit is used to adjust the current video recording frame rate to the preset normal video recording frame rate after detecting that the preset object tracking off event is triggered through the double-click operation of the real-time monitoring and recording video interface; The recording frame rate adjustment subunit is used to calculate and adjust the current video recording frame rate according to the ratio and the preset normal video recording frame rate, wherein the video recording frame rate is recorded by the smart terminal per unit time number of image frames. 4. The device according to claim 3, wherein the frame rate adjustment unit comprises: The frame dropping processing subunit is configured to perform frame dropping processing on the image frames captured by the currently recorded video according to preset rules when the moving speed of the target tracking object is lower than the preset normal moving speed.