Adaptive compression rate control
Disclosed by way of example embodiments are a system and a computer implemented method for adaptively encoding a video by changing compression rates for different frames of the video. In one aspect, two frames of a video are compared to determine a compression rate for compressing one of the two frames. Hash images may be generated for corresponding frames for the comparison. By comparing two hash images, a number of stationary objects and a number of moving objects in the two frames may be determined. Moreover, a compression rate may be determined according to the number of stationary objects and the number of moving objects.
1. A computer based method comprising:
receiving, by the computer, an input video data of a video, the video including a plurality of frames;
generating, by the computer, a first hash image data of a first frame of the plurality of frames;
generating, by the computer, a second hash image data of a second frame of the plurality of frames;
determining a number of pixels of the first frame having brightness below a brightness threshold,
generating, by the computer, a control value based on a comparison between the first hash image data and the second hash image data and based on the number of pixels having luminance below the threshold; and
encoding, by the computer, the input video data according to the control value, encoding the input video data comprising compressing the input video data according to a compression rate determined based on the control value.
2. The method of claim 1 , wherein generating the control value comprises:
determining a hamming distance between the first hash image data and the second hash image data, and
wherein the control value is generated based on the hamming distance.
3. The method of claim 1 ,
wherein the compression rate is proportional to the hamming distance.
4. The method of claim 1 , further comprising:
obtaining a difference between a first peak signal to noise ratio (PSNR) of the first frame and a second PSNR of the second frame,
wherein the control value is generated further based on the difference between the first PSNR and the second PSNR.
5. The method of claim 1 , wherein the control value is generated further based on a variance between a pixel of the first frame and the pixel of the second frame.
6. The method of claim 1 , wherein the encoding is performed by a H.264 encoder, and the control value is a constant rate factor (CRF).
7. The method of claim 1 , wherein the second frame is received subsequent to the first frame.
8. A video compressing system comprising:
a hash image generator configured to:
receive an input video data of a video, the video including a plurality of frames,
generate a first hash image data of a first frame of the plurality of frames, and
generate a second hash image data of a second frame of the plurality of frames;
an encoding controller coupled to the hash image generator, the encoding controller configured to:
determine a number of pixels of the first frame having brightness below a brightness threshold,
generate a control value based on a comparison between the first hash image data, the second hash image data and based on the number of pixels having luminance below the threshold; and
an image encoder coupled to the hash image generator and the encoding controller, the image encoder configured to:
receive the input video data of the video,
receive the control value from the encoding controller, and
encode the input video data according to the control value, encoding the input video data comprising compressing the input video data according to a compression rate determined based on the control value.
9. The system of claim 8 ,
wherein the encoding controller is further configured to determine a hamming distance between the first hash image data and the second hash image data, and
wherein the encoding controller is configured to generate the control value based on the hamming distance.
10. The system of claim 9 ,
wherein the compression rate is proportional to the hamming distance.
11. The system of claim 8 , wherein the image encoder is a H.264 encoder, and the control value is a constant rate factor (CRF).
12. The system of claim 8 , further comprising a register coupled between the hash image generator and the encoding controller, the register configured to store the first hash image data, and output the first hash image data to the encoding controller while the hash image generator outputs the second hash image data to the encoding controller.
13. A non-transitory computer readable medium storing instructions, when executed by a processor cause the processor to:
receive an input video data of a video, the video including a plurality of frames;
generate a first hash image data of a first frame of the plurality of frames;
generate a second hash image data of a second frame of the plurality of frames;
determine a number of pixels of the first frame having brightness below a brightness threshold,
generate a control value based on a comparison between the first hash image data, the second hash image data and based on the number of pixels having luminance below the threshold; and
encode the input video data according to the control value, encoding the input video data comprising compressing the input video data according to a compression rate determined based on the control value.
14. The non-transitory computer readable medium of claim 13 , wherein the instructions when executed that cause the processor to generate the control value further comprise instructions that cause the processor to:
determine a hamming distance between the first hash image data and the second hash image data, and
wherein the control value is generated based on the hamming distance.
15. The non-transitory computer readable medium of claim 14 ,
wherein the compression rate is proportional to the hamming distance.
16. The non-transitory computer readable medium of claim 13 , wherein the encoding is performed by a H.264 encoder, and the control value is a constant rate factor (CRF).