VIDEO CODING WITH TRADE-OFF BETWEEN FRAME RATE AND CHROMA FIDELITY

• US 20200137406A1
• Filed: 12/30/2019
• Published: 04/30/2020
• Est. Priority Date: 09/09/2015
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Inventors: Zhou, Minhua
• Granted Patent: US 11,019,351 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/154 Measured or subjectively estimated visual quality after decoding, e.g. measurement of distortion use of rate-distortion criteria H04N19/147
• CPC Class Codes: H04N 19/172 the region being a picture, frame or field
• CPC Class Codes: H04N 19/186 the unit being a colour or a chrominance component
• CPC Class Codes: H04N 19/44 Decoders specially adapted therefor, e.g. video decoders which are asymmetric with respect to the encoder
• CPC Class Codes: H04N 19/55 Motion estimation with spatial constraints, e.g. at image or region borders
• CPC Class Codes: H04N 19/587 involving temporal sub-sampling or interpolation, e.g. decimation or subsequent interpolation of pictures in a video sequence

Abstract

A video decoder or encoder can be used to convert and process different video streams having different combinations of frame rate and Chroma fidelity. Rather than setting the maximum sample rate of the encoder based on a Luma sample rate, the encoder'"'"'s throughput is set based on a maximum color sample rate. Additionally, the picture buffer size can be set based on a maximum number of color pictures. An input of the video decoder receives an input video stream having a given display resolution and encoded in a first format employing a first combination of frame rate and Chroma fidelity. Processing circuitry in the decoder converts the input video stream from the first format to an output video stream having a second format, the second format having the given display resolution and employing a second combination of frame rate and Chroma fidelity different from the first combination.

Claims

1. A method comprising:

receiving a compressed input video stream having a first display resolution and encoded in a first format employing a first combination of frame rate and chroma fidelity; and

decompressing the compressed input video stream to generate an output video stream having a second format, the second format having the first display resolution and a different second combination of frame rate and chroma fidelity.

2. The method claim 1, wherein decompressing the compressed input video stream includes:

increasing the frame rate of the compressed input video stream by a given factor; and

decreasing the chroma fidelity of the compressed input video stream by a corresponding factor.

3. The method claim 1, wherein decompressing the compressed input video stream includes:

decreasing the frame rate of the compressed input video stream by a given factor; and

increasing the chroma fidelity of the compressed input video stream by a corresponding factor.

4. The method claim 1, wherein the given factor is 2, and wherein increasing the chroma fidelity includes increasing the chroma fidelity from a 4:

2;

0 Chroma fidelity to a 4;

4;

4 chroma fidelity.

5. The method claim 1, further comprising:

converting the compressed input video stream from a first color space to a second color space.

6. The method of claim 5, wherein:

the first color space is RGB and the second color space is Y′

CbCr.

7. The method claim 1, further comprising:

performing inter-prediction processing on a first subset of pictures before a transition boundary and inter-prediction processing on a second subset of pictures after the transition boundary, wherein the decoder flushes a decoder picture buffer responsive to detecting the transition boundary.

8. The method claim 1, further comprising:

performing inter-prediction processing between at least one picture before a transition boundary and at least one picture after the transition boundary, responsive to determining, by the decoder, that the at least one picture before the transition boundary and the at least one picture after the transition boundary have the same color space.

9. The method claim 8, further comprising:

resampling the at least one picture before the transition boundary or the at least one picture after the transition boundary into the same color space as the other of the at least one picture before the transition boundary or the at least one picture after the transition boundary.

11. The video decoder of claim 9, wherein the processor and associated memory are further configured to:

increase the frame rate of the compressed input video stream by a given factor; and

decrease the chroma fidelity of the compressed input video stream by a corresponding factor.

12. The video decoder of claim 9, wherein the processor and associated memory are further configured to:

decrease the frame rate of the compressed input video stream by a given factor; and

increase the chroma fidelity of the compressed input video stream by a corresponding factor.

13. The video decoder of claim 9, wherein the processor and associated memory are further configured to:

convert the compressed input video stream from a first color space to a second color space.

14. The video decoder of claim 9, wherein the processor and associated memory are further configured to:

perform inter-prediction processing on a first subset of pictures before a transition boundary and inter-prediction processing on a second subset of pictures after the transition boundary, wherein the decoder flushes a decoder picture buffer responsive to detecting the transition boundary.

15. The video decoder of claim 9, wherein the processor and associated memory are further configured to:

perform inter-prediction processing between at least one picture before a transition boundary and at least one picture after the transition boundary, responsive to determining, by the decoder, that the at least one picture before the transition boundary and the at least one picture after the transition boundary have the same color space.

10. A video decoder comprising:

an input configured to receive a compressed input video stream having a display resolution and encoded in a first format employing a first combination of frame rate and chroma fidelity; and

a processor and associated memory configured to decompress the compressed input video stream to generate an output video stream having a second format, the second format having the same display resolution, but a different combination of frame rate and chroma fidelity.

16. A video decoder comprising:

an input configured to receive a compressed input video stream having a display resolution and encoded in a first format employing a first combination of frame rate and Chroma fidelity; and

processing circuitry configured to decompress the compressed input video stream to generate an output video stream having a second format, the second format having the same display resolution, but a different combination of frame rate and chroma fidelity, the processing circuitry including;

an entropy decoder coupled to the input and configured to generate quantized transform coefficients, intra prediction modes, motion data, and filter parameters;

a reconstruction circuit configured to generate currently reconstructed pictures by summing residual blocks and at least one of intra prediction blocks, inter prediction blocks, or motion-compensated prediction blocks; and

a picture buffer configured to store reference pictures and the currently reconstructed pictures during video decoding, and having a maximum capacity determined by a maximum number of color pictures.

17. The video decoder of claim 16, wherein the reconstruction circuit includes:

an inverse quantization circuit coupled to the entropy decoder and configured to generate residual blocks based on the quantized transform coefficients; and

a prediction feedback loop coupled to the entropy decoder and configured to generate residuals based on the corresponding at least one of the intra prediction blocks, inter prediction blocks, or motion-compensated prediction blocks.

18. The video decoder of claim 16, wherein the processor and associated memory are further configured to:

increase the frame rate of the compressed input video stream by a given factor; and

decrease the chroma fidelity of the compressed input video stream by a corresponding factor.

19. The video decoder of claim 16, wherein the processing circuitry is further configured to:

perform inter-prediction processing on a first subset of pictures before a transition boundary and inter-prediction processing on a second subset of pictures after the transition boundary, wherein the decoder flushes a decoder picture buffer responsive to detecting the transition boundary.

20. The video decoder of claim 16, wherein the processing circuitry is further configured to:

perform inter-prediction processing between at least one picture before a transition boundary and at least one picture after the transition boundary, responsive to determining, by the decoder, that the at least one picture before the transition boundary and the at least one picture after the transition boundary have the same color space.