Method and apparatus for selecting optimal video encoding parameter configurations

• US 8,831,089 B1
• Filed: 07/31/2006
• Issued: 09/09/2014
• Est. Priority Date: 07/31/2006
• Status: Active Grant

• Current Assignee: Geo Semiconductor Incorporated
• Original Assignee: Geo Semiconductor Incorporated
• Inventors: Zhang, Huipin
• Primary Examiner(s): Dastouri, Mehrdad
• Assistant Examiner(s): Anderson, II, James
• Application Number:
  US11/496,410
• Time in Patent Office: 2,962 Days
• Field of Search: None
• US Class Current: 375/240.01
• CPC Class Codes: H04N 19/102 characterised by the element, parameter or selection affected or controlled by the adaptive coding
• 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 19/162 User input
• CPC Class Codes: H04N 19/179 the unit being a scene or a shot
• CPC Class Codes: H04N 19/194 involving only two passes
• CPC Class Codes: H04N 19/197 including determination of the initial value of an encoding parameter H04N19/56 takes precedence

Abstract

A method for determining optimal video encoding parameters is disclosed. The method generally includes the steps of (A) storing a plurality of configurable parameters each comprising a respective trial value, (B) generating a bitstream by encoding a test sequence of pictures using (i) a plurality of non-configurable parameters fixed in a design of the encoder, (ii) the configurable parameters and (iii) a plurality of dynamic parameters adjustable in real time by the encoder, (C) generating a reconstructed sequence of pictures by decoding the bitstream, (D) generating a quality metric based on the reconstructed sequence of pictures compared with the test sequence of pictures and (E) adjusting the respective trial values to optimize the quality metric.

Claims

1. A method for determining video encoding parameters that are used by an encoder, comprising the steps of:

(A) storing a plurality of configurable parameters each comprising a respective trial value;

(B) generating a bitstream by encoding a test sequence of pictures that are not embedded in a video signal using (i) a plurality of non-configurable parameters fixed in a design of said encoder, (ii) said configurable parameters and (iii) a plurality of dynamic parameters adjustable in real time by said encoder, wherein the test sequence of pictures is predetermined at startup to include a plurality of test picture frames that represents characteristics associated with the video signal;

(C) generating a reconstructed sequence of pictures by decoding said bitstream;

(D) generating a quality metric based on said reconstructed sequence of pictures compared with said test sequence of pictures; and

(E) adjusting said respective trial values to modify said quality metric prior to encoding the video signal;

wherein step (E) comprises the sub-step of;

separating said configurable parameters into a plurality of uncorrelated subsets which are independently adjusted to modify said quality metric; and

further comprising determining an encoding performance of said encoder comprising a weighted sum of a plurality of respective encoding performances for the plurality of said test sequences of said plurality of test picture frames having a plurality of respective video signal characteristics.

2. The method according to claim 1, further comprising the step of:

repeating (i) said generation of said bitstream, (ii) said generation of said reconstructed sequence of pictures, (iii) said generation of said quality metric and (iv) said adjusting of said respective trial values until a predetermined criteria is satisfied.

3. The method according to claim 1, wherein step (E) comprises the sub-step of:

adjusting said respective trial values by trial-based searching in a value space of said respective trial values.

4. The method according to claim 3, wherein each of said configurable parameters is adjusted individually.

5. The method according to claim 4, wherein said configurable parameters are adjusted sequentially, one of said configurable parameters at a time.

6. The method according to claim 3, wherein said trial-based searching comprises a Downhill Simplex Searching.

7. The method according to claim 1, wherein said quality metric comprises a peak signal to noise metric.

8. The method according to claim 1, wherein said quality metric comprises a Video Quality Metric in accordance with a National Telecommunication and Information Administration/Institute for Telecommunications Sciences.

19. The method of claim 1, wherein, said plural video signal characteristics in the weighted sum calculation includes at least bitrate and scene information.

9. A system comprising:

a parameter module configured to (i) store a plurality of configurable parameters in a non-transitory storage medium, each configurable parameter comprising a respective trial value, and (ii) adjust said respective trial values to modify a quality metric prior to encoding the video signal;

an encoder module configured to generate a bitstream by encoding a test sequence of pictures that are not embedded in a video signal using (i) a plurality of non-configurable parameters fixed in a design of said encoder module, (ii) said configurable parameters and (iii) a plurality of dynamic parameters adjustable in real time by said encoder module,

wherein the test sequence of pictures is predetermined at startup to include a plurality of test picture frames that represents characteristics associated with the video signal;

a decoder module configured to generate a reconstructed sequence of pictures by decoding said bitstream; and

an assessment module configured to generate said quality metric based on said reconstructed sequence of pictures compared with said test sequence of pictures prior to encoding the video signal;

wherein adjusting said respective trial values to modify said quality metric comprises the sub-step of;

separating said configurable parameters into a plurality of uncorrelated subsets which are independently adjusted to modify said quality metric; and

wherein an encoding performance of said encoder module comprises a weighted sum of a plurality of respective encoding performances for a plurality of said test sequences of said pictures having a plurality of respective video signal characteristics.

10. The system according to claim 9, further comprising an optimization module configured to identify a set of said respective trial values that modifies said quality metric.

11. The system according to claim 9, wherein said encoding performance characterizing a bitrate range comprises a linear combination of said encoding performance characterizing a plurality of individual bitrates inside said bitrate range.

12. The system according to claim 9, wherein said assessment module is further configured to maximize said encoding performance.

13. The system according to claim 10, wherein said configurable parameters comprises an adaptive quantization parameter.

14. The system according to claim 10, wherein said configurable parameters comprises a quantization scaling matrix.

15. The system according to claim 10, wherein said configurable parameters comprises a quantization rounding offset.

16. The system according to claim 10, wherein said configurable parameters comprises a Lagrangian multiplier optimal coding parameter.

17. The system according to claim 10, wherein said configurable parameters comprises a skip/copy mode control parameter.

18. A system comprising:

means for (i) storing a plurality of configurable parameters each comprising a respective trial value and (ii) adjusting said respective trial values to modify a quality metric prior to encoding the video signal;

means for encoding a test sequence of pictures that are not embedded in a video signal into a bitstream using (i) a plurality of non-configurable parameters fixed in a design of said means for encoding, (ii) said configurable parameters and (iii) a plurality of dynamic parameters adjustable in real time by said means for encoding, wherein the test sequence of pictures is predetermined at startup to include a plurality of test picture frames that represents characteristics associated with the video signal;

means for decoding said bitstream into a reconstructed sequence of pictures;

means for generating said quality metric based on said reconstructed sequence of pictures compared with said test sequence of pictures prior to encoding the video signal;

wherein adjusting said respective trial values to modify said quality metric comprises the sub-step of;

separating said configurable parameters into a plurality of uncorrelated subsets which are independently adjusted to modify said quality metric; and

means for determining an encoding performance of said encoder comprising a weighted sum of a plurality of respective encoding performances for the plurality of said test sequences of said plurality of test picture frames having a plurality of respective video signal characteristics.