PARALLEL MULTIPLE BITRATE VIDEO ENCODING

• US 20110305273A1
• Filed: 06/11/2010
• Published: 12/15/2011
• Est. Priority Date: 06/11/2010
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: He, Yaming, Folta, Florin, Spears, Stacey, Gu, Chuang, Chan, Chun-Wei
• Granted Patent: US 8,705,616 B2
• Time in Patent Office: Days
• US Class Current: 375/240.02
• CPC Class Codes: H04N 19/30 using hierarchical techniques, e.g. scalability H04N19/63 takes precedence
• CPC Class Codes: H04N 19/436 using parallelised computational arrangements

Abstract

A multiple bitrate (MBR) video encoding management tool utilizes available processing units for parallel MBR video encoding. For example, instead of focusing only on multi-threading of encoding tasks for a single picture or group of pictures (GOP), the management tool parallelizes the encoding of multiple GOPs between different processing units and/or different computing systems. With this parallel MBR video encoding architecture, different GOPs can be encoded in parallel. To facilitate such parallel encoding, data dependencies between GOPs are removed. The management tool can adjust the number of GOPs to encode in parallel on a computing system so as to favor parallelism of encoding for different GOPs at the expense of parallelism of encoding inside a GOP, or vice versa, and thereby set a suitable balance between encoding latency and throughput.

Claims

1. A method of managing multiple bitrate (MBR) video encoding, the method comprising, with a video encoding management tool:

receiving pictures for video;

organizing the received pictures as multiple groups of pictures (GOPs), each group of pictures (GOP) of the multiple GOPs including one or more of the received pictures; and

providing the received pictures to multiple processing units for MBR video encoding in parallel, wherein, for each GOP of the multiple GOPs, the MBR video encoding includes encoding the GOP as multiple streams with different rates, and wherein at least two of the multiple GOPs are made available to the multiple processing units for encoding in parallel to each other.

2. The method of claim 1 further comprising, with the video encoding management tool:

detecting one or more scene changes in the received pictures; and

based at least in part on results of the scene change detection, setting one or more GOP boundaries for the received pictures, wherein the one or more GOP boundaries define the multiple GOPs.

3. The method of claim 1 wherein the multiple processing units are distributed among multiple different locations on a computer network, and wherein the providing the received pictures includes transmitting segments of at least some of the received pictures over the computer network.

4. The method of claim 1 further comprising, with the video encoding management tool:

determining a value that balances latency and processing unit utilization;

based at least in part on the determined value, determining a number of GOPs to encode in parallel on a computing system that includes two or more of the multiple processing units.

5. The method of claim 1 further comprising, with the video encoding management tool:

determining a value that balances compression efficiency and switching granularity; and

determining a GOP size based at least in part on the determined value;

wherein the received pictures are organized into the multiple GOPs based at least in part of the determined GOP size.

6. The method of claim 1 further comprising, with the video encoding management tool:

adjusting multiple settings of the video encoding management tool to trade off latency, processing unit utilization, compression efficiency and switching granularity, wherein the multiple settings include GOP size and number of GOPs to encode in parallel.

7. The method of claim 1 further comprising, with the video encoding management tool:

disabling motion estimation dependencies between the multiple GOPs for the MBR video encoding such that each of the multiple GOPs can be encoded independently of other GOPs.

8. The method of claim 1 further comprising, with the video encoding management tool:

assigning a first GOP of the multiple GOPs to a first set of one of more of the multiple processing units for encoding; and

assigning a second GOP of the multiple GOPs to a second set of one or more of the multiple processing units for encoding, wherein a computing system at a single location includes the first set of one or more processing units and the second set of one or more processing units, and wherein the first GOP and the second GOP are provided to an input memory pool of the computing system, the input memory pool being accessible to the first set of one or more processing units and accessible to the second set of one or more processing units.

9. The method of claim 8 wherein the computing system also includes the video encoding management tool, the method further comprising assembling the multiple streams for the multiple GOPs for switching during delivery to one or more video decoders.

10. The method of claim 1 further comprising, with the video encoding management tool:

assigning a first GOP of the multiple GOPs to a first set of one of more of the multiple processing units for encoding, wherein the first GOP is provided to a first input memory pool of a first computing system, the first input memory pool being accessible to the first set of one or more processing units; and

assigning a second GOP of the multiple GOPs to a second set of one or more of the multiple processing units for encoding, wherein the second GOP is provided to a second input memory pool of a second computing system different than the first computing system, the second input memory pool being accessible to the second set of one or more processing units.

11. The method of claim 1 wherein, for different pictures in a video sequence, the video encoding management tool concurrently performs the receiving, the organizing, the providing and/or the assembling while the multiple processing units perform the MBR video encoding.

12. A method of managing multiple bitrate (MBR) video encoding of multiple groups of pictures (GOPs), the method comprising, with a video encoding management tool:

determining a value that balances latency and processing unit utilization;

based at least in part on the determined value, determining a number of GOPs to encode in parallel on a computing system that includes multiple processing units; and

providing pictures to the multiple processing units for MBR video encoding in parallel of the determined number of GOPs, wherein, for each GOP of the multiple GOPs, the MBR video encoding includes encoding the GOP as multiple streams with different rates.

13. The method of claim 12 wherein the determining the number of GOPs to encode in parallel on the computing system comprises selecting between plural modes that include:

a first mode in which more of the multiple GOPs are encoded in parallel, encoding latency increases, fewer processing units per GOP are used in the MBR video encoding, and processing unit utilization increases; and

a second mode in which fewer of the multiple GOPs are encoded in parallel, encoding latency decreases, more processing units per GOP are used in the MBR video encoding, and processing unit utilization decreases.

14. The method of claim 12 wherein the value is determined based at least in part upon one or more of:

user input for a user setting of the video encoding management tool; and

a default system setting of the video encoding management tool.

15. The method of claim 12 further comprising, with the video encoding management tool, determining a GOP size based at least in part on a value that balances compression efficiency and switching granularity, wherein the number of GOPs to encode in parallel also depends at least in part on the determined GOP size.

16. A system comprising:

multiple processing units;

an input memory pool accessible to the multiple processing units; and

a video encoding management tool adapted to perform acts that include;

receiving pictures for video;

organizing the received pictures as multiple groups of pictures (GOPs), each group of pictures (GOP) of the multiple GOPs including one or more of the received pictures; and

transferring at least some of the received pictures to the input memory pool for multiple bitrate (MBR) video encoding using the multiple processing units in parallel, wherein, for each GOP of the multiple GOPs, the MBR video encoding includes encoding the GOP as multiple streams with different rates, and wherein at least two of the multiple GOPs are made available in the input memory pool for encoding in parallel to each other.

17. The system of claim 16 wherein the acts of the video encoding management tool further include, for each GOP of the multiple GOPs, assigning the GOP to one or more of the multiple processing units, and wherein the encoding the GOP includes encoding each of the multiple streams for the GOP using a multi-threaded video encoding implementation that executes on the one or more of the multiple processing units for the GOP.

18. The system of claim 16 wherein, for each GOP of the multiple GOPs, the encoding the GOP includes sequentially encoding each of the multiple streams for the GOP according to layer-to-layer dependencies for the GOP.

19. The system of claim 18 wherein motion vectors from the encoding of a first stream of the multiple streams for the GOP are used to guide motion estimation during the encoding of a second stream of the multiple streams for the GOP so as to reduce encoding time.

20. The system of claim 16 further comprising a network connection, wherein the acts of the video encoding management tool further include transmitting at least some of the received pictures to another system with one or more processing units for MBR video encoding.