Methods and/or apparatus for implementing rate distortion optimization in video compression
View Patent ↗An apparatus comprising a first circuit, a second circuit and a third circuit. The first circuit may be configured to determine one or more signal characteristics in a portion of an input video signal. The second circuit may be configured to select a multiplier value from a plurality of multiplier values in response to the signal characteristics. The third circuit may be configured to generate an encoded bitstream in response to (i) the input video signal and (ii) the selected multiplier value.
1. An apparatus comprising:
a first circuit configured to determine one or more signal characteristics in a portion of an input video signal;
a second circuit configured to select a multiplier value from a plurality of multiplier values in response to said signal characteristics, wherein the multiplier value controls operational rate and distortion behavior of the portion of the input video signal; and
a third circuit configured to generate an encoded bitstream in response to (i) said input video signal and (ii) said selected multiplier value.
2. The apparatus according to claim 1 , wherein said multiplier values comprise Lagrangian multipliers.
3. The apparatus according to claim 1 , wherein said signal characteristics comprise features relating to pictures in said input video signal.
4. The apparatus according to claim 1 , wherein said signal characteristics comprise features relating to various coding parameters used to encode said bitstream.
5. The apparatus according to claim 1 , wherein said portion of said input video signal comprises a macroblock.
6. The apparatus according to claim 5 , wherein a plurality of macroblocks having similar signal characteristics are grouped and processed together as a feature group.
7. A method for encoding a video signal, comprising the steps:
(A) determining one or more signal characteristics in a macroblock of said video signal;
(B) determining a dominant signal characteristic of said macroblock; and
(C) selecting a multiplier value from a plurality of multiplier values in response to said dominant signal characteristic, wherein said multiplier value controls operational rate and distortion behavior of the portion of the input video signal and is used to generate an encoded bitstream.
8. The method according to claim 7 , further comprising forming a featured region by (i) repeating steps (A) and (B) for a subsequent number of macroblocks and (ii) creating said featured region comprising group of said macroblocks having a dominant characteristics.
9. The method according to claim 7 , wherein said multiplier values comprises Lagrangian multipliers.
10. The method according to claim 7 , wherein said plurality of multiplier values are generated using an offline training process.
11. The method according to claim 10 , wherein said offline training comprises the steps of:
determining if said encoded bitstream has a first state indicating a maximum quality or a second state indicating additional processing is needed; and
adjusting said multiplier values when said bitstream has said second state prior to re-encoding said video signal, wherein said multiplier values are stored in a look up table when said maximum quality has been obtained.
12. The method according to claim 10 , wherein said offline training comprises the steps of:
forming a featured region by (i) repeating steps (A) and (B) for a subsequent number of macroblocks and (ii) creating said featured region comprising group of said macroblocks having a dominant characteristics; and
selecting a feature region definition value from a plurality of feature region definition values in response to said dominant signal characteristic, wherein said feature region definition value is used to generate said encoded bitstream.
13. The method according to claim 12 , wherein said selection of said feature region definition value is based on one of more of features selected from the group consisting of high frequency content, motion, color, and edge information.
14. The method according to claim 12 , wherein (i) said feature region definition value and (ii) said multiplier value are selected independently.
15. The method according to claim 12 , wherein (i) said feature region definition value and (ii) said multiplier value are selected concurrently.
16. An apparatus comprising:
a first circuit configured to generate an encoded bitstream in response to (i) a video input signal and (ii) one or more multiplier values;
a second circuit configured to determine if said encoded bitstream has a first state indicating a maximum quality or a second state indicating additional processing is needed;
a third circuit configured to adjust said one or more multiplier values when said bitstream has said second state prior to said first circuit re-encoding said video signal, wherein said third circuit stores said one or more multiplier values in a look up table when said maximum quality has been obtained.
17. The apparatus according to claim 16 , wherein said apparatus comprises a rate distortion optimization system.
18. The apparatus according to claim 16 , wherein said third circuit stores a plurality of multiplier values with each of said values corresponding to a particular characteristic of a portion of said video input signal.
19. The system according to claim 16 , wherein said system further comprises:
a fourth circuit configured to provide post-analysis of said encoded bitstream.
20. The apparatus according to claim 19 , wherein said fourth circuit provides analysis of spatial frequencies.
21. The apparatus according to claim 19 , wherein said fourth circuit provides analysis of temporal motion.
22. The apparatus according to claim 21 , wherein analysis comprises spatial frequency analysis is provided on a per macroblock basis.
23. The apparatus according to claim 22 , wherein (i) said bitstream comprises a series of frames, (ii) each of said frames comprises a plurality of macroblocks, and (iii) said temporal motion analysis is provided on a per macroblock basis.