DYNAMICALLY MODIFYING VIDEO AND CODING BEHAVIOR

• US 20090274219A1
• Filed: 04/30/2009
• Published: 11/05/2009
• Est. Priority Date: 04/30/2008
• Status: Active Grant

• Current Assignee: Zeevee, Inc.
• Original Assignee: Zeevee, Inc.
• Inventors: Benamara, Ali, Odryna, Victor, Greene, Jeremy A.
• Granted Patent: US 9,020,048 B2
• Time in Patent Office: Days
• US Class Current: 375/240.260
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/124 Quantisation
• CPC Class Codes: H04N 19/136 Incoming video signal characteristics or properties
• CPC Class Codes: H04N 19/152 by measuring the fullness of the transmission buffer
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

A system and method that provides a connection path between a video source such as a personal computer (PC) and a high-definition television (HDTV). A control is provided for varying a quality level of a video signal with respect to latency of activities provided through the video signal channel. Output picture quality versus latency is adjusted on a dynamic basis. Observed mouse activities causes the output picture quality to be decreased rapidly with an attendant decrease in latency. A decrease in output picture quality and latency is maintained until the occurrence of a particular event, such as the expiration of a time interval from a last observed mouse event. If a limited number of mouse events are observed, then the output picture quality is increased to a point at which the limited mouse activity can be accommodated with an acceptable level of latency. If limited or no mouse events are observed for a given period of time, the output picture quality is increased, either rapidly or gradually, until output picture quality is restored or another mouse event is observed.

Claims

1. A method of dynamically controlling output quality in the generation of a video output bit stream, comprising the steps of:

receiving, at a media gateway from a video source, a plurality of frames in a video input bit stream;

in an encoding step, encoding, by a video encoder within said media gateway, at least a portion of each frame in said video input bit stream to generate, at an associated output bit rate, a corresponding encoded portion of the respective frame in a video output bit stream,

wherein said encoding step is performed according to one or more of an adjustable encoding quantization step-size and an adjustable frame encoding type, and

wherein said output quality in the generation of said video output bit stream is based at least in part on one or more of the encoding quantization step-size and the frame encoding type; and

in an adjusting step, adjusting one or more of the encoding quantization step-size and the frame encoding type based on one or more of the respective output bit rates associated with the encoded portions of the respective frames in said video output bit stream, and an analysis of a change in at least some of said plurality of frames in said video input bit stream.

2. The method of claim 1 wherein said analysis of said change includes a calculation of a level of said change in at least some of said plurality of frames in said video input bit stream.

3. The method of claim 2 wherein said adjusting step further includes adjusting one or more of the encoding quantization step-size and the frame encoding type based at least in part on whether the level of said change in at least some of said plurality of frames exceeds a predetermined maximum level of change.

4. The method of claim 1:

wherein the method further includes partitioning each of said plurality of frames into a plurality of input bit stream partitions; and

wherein said encoding step includes encoding each of said plurality of input bit stream partitions to generate a corresponding encoded output bit stream partition at said associated output bit rate.

5. The method of claim 4 further including:

calculating, for each of said plurality of frames, a running average size of the output bit rates associated with the respective encoded output bit stream partitions; and

calculating, for said plurality of frames, a running average size of the running average sizes of the output bit rates associated with the respective encoded output bit stream partitions, thereby determining a running average size of the output bit rates for the entire video output bit stream.

6. The method of claim 5 wherein said adjusting step includes adjusting one or more of the encoding quantization step-size and the frame encoding type based at least in part on whether the level of said running average size of the output bit rates for the entire video output bit stream exceeds a predetermined target bit rate.

7. The method of claim 5 wherein said adjusting step further includes adjusting one or more of the encoding quantization step-size and the frame encoding type based at least in part on whether a level of said running average size of the output bit rates associated with the respective encoded output bit stream partitions is within predetermined upper and lower output bit rate limits.

8. The method of claim 4 further including calculating a level of increase in the output bit rates associated with a specified plurality of encoded output bit stream partitions.

9. The method of claim 8 wherein said adjusting step further includes adjusting one or more of the encoding quantization step-size and the frame encoding type based at least in part on whether the calculated level of increase in the output bit rates exceeds a predetermined maximum level of increase in the output bit rate.

10. A method of dynamically controlling latency in the generation of a video output bit stream, comprising the steps of:

receiving, at a media gateway from a video source, a plurality of frames in a video input bit stream;

in an encoding step, encoding, by a video encoder within said media gateway, said plurality of frames in said video input bit stream to generate a plurality of encoded frames in a video output bit stream;

in a transmitting step, transmitting, at an adjustable frame transmission rate, at least a portion of said plurality of encoded frames in said video output bit stream to a frame buffer within a video display apparatus, for subsequent display on said video display apparatus at a specified frame display rate,

wherein said latency in the generation of said video output bit stream is based at least in part on the frame transmission rate; and

in an adjusting step, responsive to a predetermined event, adjusting the frame transmission rate to be greater than or less than said specified frame display rate to dynamically control said latency in the generation of said video output bit stream.

11. The method of claim 10:

wherein said plurality of frames includes at least one intra-coded frame and at least one inter-coded frame, each of the intra-coded and inter-coded frames having associated frame information;

wherein the method further includes, in a generating step, generating at least one inter-coded frame without indicating, in its associated frame information, differences between the generated inter-coded frame and one or more previously coded intra-coded frames and inter-coded frames; and

wherein said encoding step includes, at least at some times, inserting said at least one inter-coded frame generated in said generating step in said plurality of encoded frames in said video output bit stream.

12. The method of claim 11:

wherein said adjusting step includes adjusting said frame transmission rate to be greater than said specified frame display rate; and

wherein said transmitting step includes transmitting, at the adjusted frame transmission rate, said plurality of encoded frames including the inserted inter-coded frames.

13. The method of claim 10 wherein said method further includes dropping, at least at some times, at least one encoded frame in said plurality of encoded frames in said video output bit stream.

14. The method of claim 13:

wherein said adjusting step includes adjusting said frame transmission rate to be less than said specified frame display rate; and

wherein said transmitting step includes transmitting, at the adjusted frame transmission rate, said plurality of encoded frames without the at least one dropped encoded frame.

15. The method of claim 10:

wherein said method further includes detecting said predetermined event at said media gateway, the detected predetermined event corresponding to the detection of the presence of at least one user input; and

wherein said adjusting step includes, responsive to the detection of the presence of the user input, adjusting the frame transmission rate to be less than said specified frame display rate to reduce said latency in the generation of said video output bit stream.

16. The method of claim 10:

wherein said method further includes detecting said predetermined event at said media gateway, the detected predetermined event corresponding to the detection of the absence of at least one user input; and

wherein said adjusting step includes, responsive to the detection of the absence of the user input, adjusting the frame transmission rate to be greater than said specified frame display rate, thereby raising said latency in the generation of said video output bit stream.

17. A method of dynamically controlling latency in the generation of a video output signal, comprising the steps of:

in a first encoding step, in the absence of an indication of a user input for a predetermined time period, encoding, by a video encoder within a media gateway, a video input signal to generate a video output signal at a first output bit rate, thereby obtaining a first level of latency in the generation of said video output signal; and

in a second encoding step, responsive to an indication of a predetermined user input that would affect said video output signal, encoding, by said video encoder within said media gateway, said video input signal to generate said video output signal at a second output bit rate, thereby obtaining a second level of latency, less than said first level of latency, in the generation of said video output signal.

18. The method of claim 17:

wherein said video input signal includes a first video input signal, and a second video input signal representing said predetermined user input that would affect said video output signal; and

wherein said second encoding step includes encoding said first video input signal to generate a first video output signal at said second output bit rate, and encoding said second video input signal representing said predetermined user input to generate a second video output signal at said second output bit rate, said video output signal being a composite of said first video output signal and said second video output signal.

19. The method of claim 18 wherein said second encoding step includes encoding said first video input signal to generate said first video output signal at said second output bit rate, and encoding said second video input signal representing said predetermined user input to generate said second video output signal at said second output bit rate, said predetermined user input corresponding to a computer cursor input.

20. The method of claim 18 wherein said second encoding step includes encoding said first video input signal to generate said first video output signal at said second output bit rate, and encoding said second video input signal representing said predetermined user input to generate said second video output signal at said second output bit rate, said predetermined user input corresponding to a computer keyboard input.