Dynamic selection of parameter sets for transcoding media data

• US 8,892,764 B1
• Filed: 01/06/2014
• Issued: 11/18/2014
• Est. Priority Date: 09/08/2009
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Ebersviller, Matthew Robert
• Primary Examiner(s): Tang, Karen
• Application Number:
  US14/148,344
• Time in Patent Office: 316 Days
• Field of Search: 709/231, 709/232
• US Class Current: 709/231
• 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 19/196 being specially adapted for the computation of encoding parameters, e.g. by averaging previously computed encoding parameters processing of motion vectors H04N19/513
• CPC Class Codes: H04N 19/40 using video transcoding, i.e. partial or full decoding of a coded input stream followed by re-encoding of the decoded output stream
• CPC Class Codes: H04N 19/46 Embedding additional information in the video signal during the compression process H04N19/517, H04N19/68, H04N19/70 take precedence
• CPC Class Codes: H04N 19/61 in combination with predictive coding

Abstract

An iterative operation is performed at a computing device to identify a parameter set for an initial segment. A parameter set for an initial segment includes a plurality of encoding parameters and values assigned to the encoding parameters. The initial segment is re-encoded using the parameter set, thereby generating a transcoded segment. In some embodiments, the transcoded segment is transmitted to a client computing device that presents media represented by the transcoded segment.

Claims

1. A method, comprising:

receiving, by a device including a processor, a media data stream; and

performing, by the device, an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receiving a current segment of the media data stream;

transcoding the current segment into a first transcoded segment using a current parameter set that was employed to transcode a previous segment of the media data stream;

determining whether the current parameter set is a final parameter set;

in response to determining that the current parameter is the final parameter set, outputting the first transcoded segment as part of the transcoded media data stream; and

in response to determining that the current parameter is not the final parameter set;

determining a first fitness score of the first transcoded segment;

determining whether the first fitness score exceeds a fitness score threshold;

mutating the current parameter set into a mutated parameter set;

transcoding the current segment into a second transcoded segment using the mutated parameter set;

determining a second fitness score of the second transcoded segment;

determining whether the second fitness score is greater than the first fitness score;

in response to determining that the second fitness score is not greater than the first fitness score, outputting the first transcoded segment as part of the transcoded media data stream; and

in response to determining that the second fitness score is greater than the first fitness score;

setting the mutated parameter set as the current parameter set;

outputting the second transcoded segment as part of the transcoded media data stream;

determining whether the second fitness score exceeds a fitness score threshold; and

in response to determining that the second fitness score exceeds the fitness score threshold setting the current parameter set as the final parameter set.

2. The method of claim 1, wherein the respective current segments at each iteration are part of a series of segments of the media data stream.

3. The method of claim 1, further comprising:

transmitting, by the device, the transcoded media data stream to a client device via a computer communications network.

4. The method of claim 1,

wherein the media data stream represents live video;

and

wherein the transcoded media data stream represents live video.

5. The method of claim 1, wherein the transcoded media data stream has a lower bit rate than the media data stream.

6. A non-transitory computer readable medium having instructions stored thereon that, in response to execution, cause system including a processor to perform operations comprising:

receiving a media data stream; and

performing an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receiving a current segment of the media data stream;

transcoding the current segment into a first transcoded segment using a current parameter set that was employed to transcode a previous segment of the media data stream;

determining whether the current parameter set is a final parameter set;

in response to determining that the current parameter is the final parameter set, outputting the first transcoded segment as part of the transcoded media data stream; and

in response to determining that the current parameter is not the final parameter set;

determining a first fitness score of the first transcoded segment;

determining whether the first fitness score exceeds a fitness score threshold;

mutating the current parameter set into a mutated parameter set;

transcoding the current segment into a second transcoded segment using the mutated parameter set;

determining a second fitness score of the second transcoded segment;

determining whether the second fitness score is greater than the first fitness score;

in response to determining that the second fitness score is not greater than the first fitness score, outputting the first transcoded segment as part of the transcoded media data stream; and

in response to determining that the second fitness score is greater than the first fitness score;

setting the mutated parameter set as the current parameter set;

outputting the second transcoded segment as part of the transcoded media data stream;

determining whether the second fitness score exceeds a fitness score threshold; and

in response to determining that the second fitness score exceeds the fitness score threshold setting the current parameter set as the final parameter set.

7. The non-transitory computer readable medium of claim 6, wherein the respective current segments at each iteration are part of a series of segments of the media data stream.

8. The non-transitory computer readable medium of claim 6, further comprising:

transmitting, by the device, the transcoded media data stream to a client device via a computer communications network.

9. The non-transitory computer readable medium of claim 6,

wherein the media data stream represents live video;

and

wherein the transcoded media data stream represents live video.

10. The non-transitory computer readable medium of claim 6, wherein the transcoded media data stream has a lower bit rate than the media data stream.

11. A system, comprising:

a memory, communicatively coupled to a processor, the memory having stored therein executable instructions, comprising;

a parameter identification module configured to;

receive a media data stream; and

perform an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receive a current segment of the media data stream;

transcode the current segment into a first transcoded segment using a current parameter set that was employed to transcode a previous segment of the media data stream;

determine whether the current parameter set is a final parameter set;

in response to a determination that the current parameter is the final parameter set, output the first transcoded segment as part of the transcoded media data stream; and

in response to a determination that the current parameter is not the final parameter set;

 

calculate a first fitness score of the first transcoded segment;

 

determine whether the first fitness score exceeds a fitness score threshold;

 

mutate the current parameter set into a mutated parameter set;

 

transcode the current segment into a second transcoded segment using the mutated parameter set;

 

determine a second fitness score of the second transcoded segment;

 

determine whether the second fitness score is greater than the first fitness score;

 

in response to a determination that the second fitness score is not greater than the first fitness score, outputting the first transcoded segment as part of the transcoded media data stream; and

 

in response to a determination that the second fitness score is greater than the first fitness score;

 

set the mutated parameter set as the current parameter set;

 

output the second transcoded segment as part of the transcoded media data stream;

 

determine whether the second fitness score exceeds a fitness score threshold; and

 

in response to a determination that the second fitness score exceeds the fitness score threshold setting the current parameter set as the final parameter set.

12. The system of claim 11, wherein the respective current segments at each iteration are part of a series of segments of the media data stream.

13. The system of claim 11,

wherein the media data stream represents live video;

and

wherein the transcoded media data stream represents live video.

14. The system of claim 11, wherein the transcoded media data stream has a lower bit rate than the media data stream.

15. A method, comprising:

receiving, by a device including a processor, a media data stream; and

performing, by the device, an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receiving a current series of segments of the media data stream;

determine whether a final parameter set has been selected;

in response to determining that the final parameter set has been selected;

transcoding each segment in the current series of segments into a current series of transcoded segments using the final parameter set; and

outputting the current series of transcoded segments as part of the transcoded media data stream; and

in response to determining that the final parameter set has not been selected;

transcoding each segment in the current series of segments into the current series of transcoded segments using different parameter sets in a current generation of parameter sets;

outputting the current series of transcoded segments as part of the transcoded media data stream;

determining respective fitness scores of transcoded segments in the current series of transcoded segments;

determining whether at least one of the fitness scores exceeds a fitness score threshold;

determining whether a generation limit is reached;

in response to determining that the generation limit has been reached or at least one of the fitness scores exceeds the fitness score threshold, selecting a parameter set employed for encoding a segment into a transcoded segment having a fitness score greater than each other transcoded segment in the current series of transcoded segments as the final parameter set; and

in response to determining that the generation limit has not been reached and none of the fitness scores exceeds the fitness score threshold;

determining selection probabilities of the parameter sets in the current generation of parameter sets; and

performing the following steps until a new generation of parameter sets includes a threshold number of parameter sets;

 

selecting parent parameter sets based on the selection probabilities of the parameter sets in the current generation of parameter sets; and

 

generating a child parameter set in the new generation of parameter sets by recombining values of encoding parameters in the parent parameter sets; and

setting the new generation of parameter sets as the current generation of parameter sets.

16. A non-transitory computer readable medium having instructions stored thereon that, in response to execution, cause system including a processor to perform operations comprising:

receiving a media data stream; and

performing an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receiving a current series of segments of the media data stream;

determining whether a final parameter set has been selected;

in response to determining that the final parameter set has been selected;

transcoding each segment in the current series of segments into a current series of transcoded segments using the final parameter set; and

outputting the current series of transcoded segments as part of the transcoded media data stream; and

in response to determining that the final parameter set has not been selected;

transcoding each segment in the current series of segments into the current series of transcoded segments using different parameter sets in a current generation of parameter sets;

outputting the current series of transcoded segments as part of the transcoded media data stream;

calculating respective fitness scores of transcoded segments in the current series of transcoded segments;

determining whether at least one of the fitness scores exceeds a fitness score threshold;

determining whether a generation limit is reached;

in response to determining that the generation limit has been reached or at least one of the fitness scores exceeds the fitness score threshold, selecting a parameter set employed for encoding a segment into a transcoded segment having a fitness score greater than each other transcoded segment in the current series of transcoded segments as the final parameter set; and

in response to determining that the generation limit has not being reached and none of the fitness scores exceeds the fitness score threshold;

determining selection probabilities of the parameter sets in the current generation of parameter sets; and

performing the following steps until a new generation of parameter sets includes a threshold number of parameter sets;

 

selecting parent parameter sets based on the selection probabilities of the parameter sets in the current generation of parameter sets; and

 

generating a child parameter set in the new generation of parameter sets by recombining values of encoding parameters in the parent parameter sets; and

setting the new generation of parameter sets as the current generation of parameter sets.

17. A system, comprising:

a memory, communicatively coupled to a processor, the memory having stored therein executable instructions, comprising;

a parameter identification module configured to;

receive a media data stream; and

perform an iterative operation for transcoding the media data stream into a transcoded media data stream, wherein each iteration of the iterative operation comprises;

receive a current series of segments of the media data stream;

determine whether a final parameter set has been selected;

in response to a determination that the final parameter set has been selected;

transcode each segment in the current series of segments into a current series of transcoded segments using the final parameter set; and

output the current series of transcoded segments as part of the transcoded media data stream;

in response to a determination that the final parameter set has not been selected;

transcode each segment in the current series of segments into the current series of transcoded segments using different parameter sets in a current generation of parameter sets;

output the current series of transcoded segments as part of the transcoded media data stream;

determine respective fitness scores of transcoded segments in the current series of transcoded segments;

determine whether at least one of the fitness scores exceeds a fitness score threshold;

determine whether a generation limit is reached;

in response to a determination that the generation limit has been reached or at least one of the fitness scores exceeds the fitness score threshold, selecting a parameter set employed for encoding a segment into a transcoded segment having a fitness score greater than each other transcoded segment in the current series of transcoded segments as the final parameter set;

in response to a determination that the generation limit has not being reached and none of the fitness scores exceeds the fitness score threshold;

 

determine selection probabilities of the parameter sets in the current generation of parameter sets; and

 

perform the following until a new generation of parameter sets includes a threshold number of parameter sets;

 

select parent parameter sets based on the selection probabilities of the parameter sets in the current generation of parameter sets; and

 

generate a child parameter set in the new generation of parameter sets by recombining values of encoding parameters in the parent parameter sets; and

 

set the new generation of parameter sets as the current generation of parameter sets.