Distributed architecture for encoding and delivering video content

Patent metadata

Field	Value
Publication number	US-11483580-B2
Application number	US-201313915499-A
Country	US
Kind code	B2
Filing date	Jun 11, 2013
Priority date	Jun 12, 2012
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A split architecture for encoding a video stream. A source encoder may encode a video content stream to obtain an encoded bitstream and a side information stream. The side information stream includes information characterizing rate and/or distortion estimation functions per block of the video content stream. Also, a different set of estimation functions may be included per coding mode. The encoded bitstream and side information stream may be received by a video transcoder, which transcodes the encoded bitstream to a client-requested picture resolution, according to a client-requested video format and bit rate. The side information stream allows the transcoder to efficiently and compactly perform rate control for its output bitstream, which is transmitted to the client device. This split architecture may be especially useful to operators of content delivery networks.

First claim

What is claimed is:

1. A system comprising:
a memory that stores a collection of video content items, wherein each of the video content items includes an encoded video stream and metadata that characterizes properties of a given source video stream corresponding to the encoded video stream;
a plurality of video transcoder devices; and
a controller, wherein, in response to each of a plurality of content requests for a given one of the video content items from a respective plurality of user devices, the controller is configured to assign an available one of the plurality of video transcoder devices to serve the respective user device, wherein the user devices have respectively different configurations of video processing capability (VPC), wherein each assigned video transcoder device is configured to:
receive the encoded video stream and metadata of the given video content item, wherein the metadata indicates:
rate estimation information for a plurality of encoding modes for a plurality of blocks of the encoded video stream, wherein the rate estimation information specifies an estimated number of bits generated by encoding ones of the blocks using ones of multiple different quantization step sizes and ones of the encoding modes; and
distortion estimation information that specifies multiple points on a distortion curve, wherein the points are generated based on discrete cosine transforms of ones of the plurality of blocks and processing of un-quantized coefficient outputs of the transform, wherein ones of the points indicate estimated distortion at a particular quantization step size;

compute aggregate rate estimation information and aggregate distortion estimation information by summing over the rate estimation information and distortion estimation, respectively, corresponding to different ones of the plurality of blocks;
select an encoding mode and quantization size for a transcoding of the encoded video stream based at least in part on the aggregate rate estimation information and the aggregate distortion estimation information and according to the VPC configuration of the respective user device;
transcode the encoded video stream using the selected encoding mode and quantization size, in order to obtain a respective target encoded video stream; and
transmit the respective target encoded video stream to the respective user device through a communication medium.

2. The system of claim 1 , wherein the rate estimation information includes one or more rate information streams that each characterize a corresponding rate estimation function R k (q) per block of the corresponding encoded video stream, assuming block prediction based on the respective encoding mode, wherein q is a quantization step size.

3. The system of claim 1 , wherein the metadata includes one or more candidate motion vectors per block of the encoded video stream of the given content item.

4. The system of claim 1 , wherein the communication medium is a wireless transmission medium.

5. The system of claim 4 , wherein at least one of the plurality of video transcoder devices is coupled to or incorporated as part of a base station of a wireless communication network, wherein one or more of the user devices are configured for wireless communication with the base station.

6. The system of claim 1 , wherein the controller is configured to assign a first of the plurality of video transcoder devices to different ones of the user devices at different times.

7. The system of claim 1 , further comprising:
a source encoder configured to encode source video streams to generate respective ones of the content items.

8. The system of claim 1 , wherein the metadata of each video content item includes one or more distortion information streams corresponding to one or more respective coding modes, wherein each distortion information stream DIS k of the one or more distortion information streams characterizes a corresponding distortion function D k (q) per block of the encoded video stream of the video content item, assuming block prediction based on the respective coding mode, wherein q is a quantization step size.

9. The system of claim 1 , wherein a first video transcoder device of the plurality of video transcoder devices is configured to perform said transcoding by:
decoding the encoded video stream to obtain a decoded video stream;
scaling the decoded video stream to a target picture resolution of the respective user device, in order to obtain a scaled video stream; and
encoding the scaled video stream using the metadata and according to the VPC configuration of the respective user device, in order to obtain the respective target encoded video stream.

10. The system of claim 9 , wherein the controller is configured to:
receive reports from the user device being served by the first video transcoder device, wherein each of the reports includes analytical information from the user device; and
in response to each of the reports, update a target bit rate and/or the target picture resolution used by the first video transcoder device to encode the scaled video stream.

11. The system of claim 10 , wherein the analytical information includes information about quality of a link between the first video transcoder device and the user device.

12. The system of claim 11 , wherein the controller is configured to decrease or increase the target bit rate and/or the target picture resolution used by the first video transcoder device when the information about link quality indicates that the link quality has decreased or increased, respectively.

13. The system of claim 10 , wherein the analytical information includes information about quality of video recovered from the respective target encoded video stream transmitted by the first video transcoder device.

14. The system of claim 13 , wherein the controller is configured to decrease or increase the target bit rate and/or the target picture resolution used by the first video transcoder device when the information about video quality indicates that the video quality has decreased or increased, respectively.

15. The system of claim 9 , wherein the controller is configured to:
receive reports from the user device being served by the first video transcoder device, wherein each of the reports includes a corresponding update to the VPC configuration of the user device; and
in response to each of the reports, update the target picture resolution used by the first video transcoder device to encode the scaled video stream.

16. The system of claim 1 , wherein the VPC configuration of each user device includes an identification of one or more of:
a video coding format requested by the user device; and
a target picture resolution requested by the user device.

17. The system of claim 1 , wherein the VPC configurations of the respective user devices span an M-dimensional configuration space, wherein M is at least two, wherein the M-dimensional configuration space has at least a first dimension corresponding to a choice of video format and a second dimension corresponding to a selection of picture resolution.

18. The system of claim 1 , wherein the controller is configured to:
store the target encoded video stream generated by a given one of the plurality of video transcoder devices that has been assigned to serve a first of the user devices; and
direct a transmission of the stored target encoded video stream to a second user device in response to detecting that the second user device has a same or similar VPC configuration as the first user device.

Assignees

• Coherent Logix Inc

Inventors

• Bruns Michael W
• Solka Michael B
• Dobbs Carl S
• Hunt Martin A
• Doerr Michael B
• Eng Tommy K

Classifications

• H04N19/61

  in combination with predictive coding · CPC title

• H04N19/513

  Processing of motion vectors · CPC title

• H04N19/46

  Embedding additional information in the video signal during the compression process (H04N19/517, H04N19/68, H04N19/70 take precedence) · CPC title

• H04N19/19

  using optimisation based on Lagrange multipliers · CPC title

• H04N19/176

  the region being a block, e.g. a macroblock · CPC title