Skipping evaluation stages during media encoding

Patent metadata

Field	Value
Publication number	US-10924743-B2
Application number	US-201515549261-A
Country	US
Kind code	B2
Filing date	Feb 6, 2015
Priority date	Feb 6, 2015
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

Various innovations in media encoding are presented herein. In particular, the innovations can reduce the computational complexity of encoding by selectively skipping certain evaluation stages during encoding. For example, based on analysis of decisions made earlier in encoding or based on analysis of media to be encoded, an encoder can selectively skip evaluation of certain coding tools (such as residual coding or rate-distortion-optimized quantization), skip evaluation of certain values for parameters or settings (such as candidate unit sizes or transform sizes, or candidate partition patterns for motion compensation), and/or skip evaluation of certain coding modes (such as frequency transform skip mode) that are not expected to improve rate-distortion performance during encoding.

First claim

We claim:

1. In a computer system, a method of media encoding comprising:
encoding a first picture among multiple pictures to produce encoded data for the first picture;
determining a threshold unit size for the first picture, the threshold unit size indicating a unit size at or below which a threshold proportion of content of the first picture is reached, the threshold proportion being reached when units no larger than the threshold unit size cover the threshold proportion of the content of the first picture;
outputting the encoded data for the first picture;
encoding a second picture among the multiple pictures to produce encoded data for the second picture, the second picture following the first picture in coding order, including limiting unit size for at least part of the second picture based at least in part on the threshold unit size for the first picture; and
outputting the encoded data for the second picture.

2. The method of claim 1 , wherein the content of the first picture, for purposes of the threshold unit size, is intra-picture-coded units of the first picture.

3. The method of claim 2 , wherein the first picture is entirely encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

4. The method of claim 2 , wherein the first picture is partially encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

5. The method of claim 1 , wherein the threshold proportion is between 80% and 95%, wherein the threshold unit size for the first picture is threshold coding unit (“CU”) size for the first picture, and wherein the unit size for the at least part of the second picture is CU size.

6. The method of claim 1 , wherein the unit size is limited for the at least part of the second picture by skipping evaluation of candidate unit sizes larger than the threshold unit size in the at least part of the second picture.

7. The method of claim 1 , wherein the encoding the first picture includes splitting the first picture into multiple units, each of the multiple units of the first picture having one of multiple candidate unit sizes, wherein the threshold unit size is one of the multiple candidate unit sizes, and wherein the encoding the second picture includes splitting the second picture into multiple units, each of the multiple units of the second picture having one of the multiple candidate unit sizes that is no larger than the threshold unit size.

8. The method of claim 1 , wherein the threshold proportion of content is a measure of sample values.

9. One or more computer-readable storage devices having stored thereon computer-executable instructions for causing one or more processing units, when programmed thereby, to perform media encoding operations comprising:
encoding a first picture among multiple pictures to produce encoded data for the first picture;
determining a threshold unit size for the first picture, the threshold unit size indicating a unit size at or below which a threshold proportion of content of the first picture is reached, the threshold proportion being reached when units no larger than the threshold unit size cover the threshold proportion of the content of the first picture;
outputting the encoded data for the first picture;
encoding a second picture among the multiple pictures to produce encoded data for the second picture, the second picture following the first picture in coding order, including limiting unit size for at least part of the second picture based at least in part on the threshold unit size for the first picture; and
outputting the encoded data for the second picture.

10. The one or more computer-readable storage devices of claim 9 , wherein the content of the first picture, for purposes of the threshold unit size, is intra-picture-coded units of the first picture.

11. The one or more computer-readable storage devices of claim 10 , wherein the first picture is entirely encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

12. The one or more computer-readable storage devices of claim 10 , wherein the first picture is partially encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

13. The one or more computer-readable storage devices of claim 9 , wherein the threshold proportion is between 80% and 95%, wherein the threshold unit size for the first picture is threshold coding unit (“CU”) size for the first picture, and wherein the unit size for the at least part of the second picture is CU size.

14. The one or more computer-readable storage devices of claim 9 , wherein the unit size is limited for the at least part of the second picture by skipping evaluation of candidate unit sizes larger than the threshold unit size in the at least part of the second picture.

15. A computer system comprising:
one or more picture buffers configured to store multiple pictures; and
a video encoder configured to perform operations comprising:
encoding a first picture among the multiple pictures to produce encoded data for the first picture;
determining a threshold unit size for the first picture, the threshold unit size indicating a unit size at or below which a threshold proportion of content of the first picture is reached, the threshold proportion being reached when units no larger than the threshold unit size cover the threshold proportion of the content of the first picture;
outputting the encoded data for the first picture;
encoding a second picture among the multiple pictures to produce encoded data for the second picture, the second picture following the first picture in coding order, including limiting unit size for at least part of the second picture based at least in part on the threshold unit size for the first picture; and
outputting the encoded data for the second picture.

16. The computer system of claim 15 , wherein the content of the first picture, for purposes of the threshold unit size, is intra-picture-coded units of the first picture.

17. The computer system of claim 16 , wherein the first picture is entirely encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

18. The computer system of claim 16 , wherein the first picture is partially encoded using intra-picture-coded units, wherein the second picture is at least partially encoded using inter-picture-coded units, and wherein unit size is limited for any intra-picture-coded units in the second picture.

19. The computer system of claim 15 , wherein the threshold proportion is between 80% and 95%, wherein the threshold unit size for the first picture is threshold coding unit (“CU”) size for the first picture, and wherein the unit size for the at least part of the second picture is CU size.

20. The computer system of claim 15 , wherein the unit size is limited for the at least part of the second picture by skip

Assignees

• Microsoft Technology Licensing Llc
• Li Bin
• Xu Jizheng

Inventors

• Li Bin
• Xu Jizheng

Classifications

• H04N19/172

  the region being a picture, frame or field · CPC title

• H04N19/127

  Prioritisation of hardware or computational resources · CPC title

• H04N19/52

  by predictive encoding · CPC title

• H04N19/147

  according to rate distortion criteria (rate-distortion as a criterion for motion estimation H04N19/567) · CPC title

• H04N19/119

  Adaptive subdivision aspects, e.g. subdivision of a picture into rectangular or non-rectangular coding blocks · CPC title