BIT RATE STREAM SWITCHING

• US 20100158101A1
• Filed: 12/18/2009
• Published: 06/24/2010
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Netflix, Inc.
• Original Assignee: Netflix, Inc.
• Inventors: Lai, Yung-Hsiao, Zollinger, James Mitch, WU, CHUNG-PING, Ronca, David Randall, Kaiser, Christian
• Granted Patent: US 9,060,187 B2
• Time in Patent Office: Days
• US Class Current: 375/240.10
• CPC Class Codes: H04L 65/60 Network streaming of media packets
• CPC Class Codes: H04L 65/70 Media network packetisation
• CPC Class Codes: H04N 19/115 Selection of the code volume for a coding unit prior to coding
• CPC Class Codes: H04N 19/164 Feedback from the receiver or from the transmission channel
• CPC Class Codes: H04N 19/167 Position within a video image, e.g. region of interest [ROI]
• CPC Class Codes: H04N 19/177 the unit being a group of pictures [GOP]
• 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
• CPC Class Codes: H04N 21/23424 involving splicing one content stream with another content stream, e.g. for inserting or substituting an advertisement
• CPC Class Codes: H04N 21/23439 for generating different versions
• CPC Class Codes: H04N 21/23611 Insertion of stuffing data into a multiplex stream, e.g. to obtain a constant bitrate synchronisation arrangements in time-division multiplex systems using bit stuffing for systems with different or fluctuating information rates H04J3/073
• CPC Class Codes: H04N 21/2368 Multiplexing of audio and video streams
• CPC Class Codes: H04N 21/26258 for generating a list of items to be played back in a given order, e.g. playlist, or scheduling item distribution according to such list retrieval of multimedia data based on playlists G06F16/40
• CPC Class Codes: H04N 21/2662 Controlling the complexity of the video stream, e.g. by scaling the resolution or bitrate of the video stream based on the client capabilities
• CPC Class Codes: H04N 21/4325 by playing back content from the storage medium reproduction of recorded television signals H04N5/76; reproduction of recorded television signals H04N9/79
• CPC Class Codes: H04N 21/4346 involving stuffing data, e.g. packets or bytes synchronisation arrangements in time-division multiplex systems with different or fluctuating information rates H04J3/073
• CPC Class Codes: H04N 21/44016 involving splicing one content stream with another content stream, e.g. for substituting a video clip
• CPC Class Codes: H04N 21/44029 for generating different versions
• CPC Class Codes: H04N 21/4621 Controlling the complexity of the content stream or additional data, e.g. lowering the resolution or bit-rate of the video stream for a mobile client with a small screen arrangements for using the results of monitoring on user's side in broadcast systems H04H60/65; flow control in packet networks H04L47/10

Abstract

Embodiments for changing bit rates in streaming media are provided. As portions of a streaming media file are downloaded for playback, the size of the portion is compared with an expected size determined prior to initiating playback of streaming AV data. The portion of the media file may be padded such that the size of the portion matches the size specified prior to initiating playback of streaming AV data.

Claims

1. A computer-implemented method for switching a bit rate at which audiovisual data is streamed over a data communications network from a media delivery system to a client device, the method comprising:

prior to initiating playback of the audiovisual data, configuring a decoder on the client device to decode and playback a plurality of portions of the audiovisual data, wherein each portion is specified as having a size corresponding to an encoding of the portion at a first bit rate;

receiving, over the data communications network, a first portion of the audiovisual data, wherein the first portion of the audiovisual data is encoded at a second bit rate, different from first bit rate specified for the first portion; and

padding the first portion of the audiovisual data such that the size of the first portion of the audiovisual data matches the specified size corresponding to the encoding of the portion of the audiovisual data encoded at the first bit rate.

2. The computer-implemented method of claim 1, wherein configuring the decoder comprises:

receiving a plurality of file headers each associated with a corresponding encoding of the audiovisual data, including a file header associated with an encoding of the audiovisual data at the first and second bit rates, wherein each file header specifies a size and a duration for each portion of the audiovisual data present in the corresponding encoding; and

generating, from the plurality of file headers, a playlist information file storing one or more clip information files, wherein each clip information file describes one of the portions of audiovisual data to be streamed from the media delivery system

3. The computer-implemented method of claim 2, wherein each clip information file stores an indication of the largest encoded size, from the plurality of file headers, for one or more sequential portions of the audiovisual data.

4. The computer-implemented method of claim 2, wherein each clip information file indicates a sequence of one or more groups of pictures (GOPs) in the portion of the audiovisual data corresponding to a respective clip information file.

5. The computer-implemented method of claim 4, wherein padding the first portion of the audiovisual data comprises padding at least one GOP in the portion of the audiovisual data such that the size of each GOP matches the size specified in the respective clip information file.

6. The computer-implemented method of claim 1, further comprising, passing the padded first portion of the audiovisual data to the decoder, wherein the decoder decodes the padded first portion of audiovisual data for output to a display device.

7. The computer-implemented method of claim 1, wherein padding the first portion of the audiovisual data comprises adding one or more NULL packets to a transport stream.

8. The computer-implemented method of claim 1, wherein the media delivery system multiplexes an elementary audio stream and an elementary video stream to generate the plurality of portions of audiovisual data streamed to the client device.

9. The computer-implemented method of claim 1, wherein the client device is one of a Blu-Ray®

disk player, set-top box, and a digital video recorder.

10. A computer-readable storage medium including instructions that, when executed by a processing unit, cause the processing unit to seamlessly switch a bit rate at which audiovisual data is streamed over a data communications network from a media delivery system to a client device, by performing the steps of:

prior to initiating playback of the audiovisual data, configuring a decoder on the client device to decode and playback a plurality of portions of the audiovisual data, wherein each portion is specified as having a size corresponding to an encoding of the portion at a first bit rate;

receiving, over the data communications network, a first portion of the audiovisual data, wherein the first portion of the audiovisual data is encoded at a second bit rate, different from first bit rate specified for the first portion; and

padding the first portion of the audiovisual data such that the size of the first portion of the audiovisual data matches the specified size corresponding to the encoding of the portion of the audiovisual data encoded at the first bit rate.

11. The computer-readable storage medium of claim 10, wherein configuring the decoder on the client device to decode and playback the plurality of portions of the audiovisual data comprises:

receiving a plurality of file headers each associated with a corresponding encoding of the audiovisual data, including a file header associated with an encoding of the audiovisual data at the first and second bit rates, wherein each file header specifies a size and a duration for each portion of the audiovisual data present in the corresponding encoding; and

generating, from the plurality of file headers, a playlist information file storing one or more clip information files, wherein each clip information file describes one of the portions of audiovisual data to be streamed from the media delivery system.

12. The computer-readable storage medium of claim 11, wherein each clip information file stores an indication of the largest encoded size, from the plurality of file headers, for one or more sequential portions of the audiovisual data.

13. The computer-readable storage medium of claim 11, wherein each clip information file indicates a sequence of one or more groups of pictures (GOPs) in the portion of the audiovisual data corresponding to a respective clip information file.

14. The computer-readable storage medium of claim 13, wherein padding the first portion of the audiovisual data comprises padding at least one GOP in the portion of the audiovisual data such that the size of each GOP matches the size specified in the respective clip information file.

15. The computer-readable storage medium of claim 10, wherein the steps further comprise, passing the padded first portion of the audiovisual data to the decoder, wherein the decoder decodes the padded first portion of audiovisual data for output to a display device.

16. The computer-readable storage medium of claim 10, wherein padding the first portion of the audiovisual data comprises adding one or more NULL packets to a transport stream.

17. The computer-readable storage medium of claim 10, wherein the media delivery system multiplexes an elementary audio stream and an elementary video stream to generate the plurality of portions of audiovisual data streamed to the client device.

23. The digital media content player of claim 17, wherein the processing unit coupled to the memory is further configured to pass the padded first portion of the audiovisual data to the decoder, wherein the decoder decodes the padded first portion of audiovisual data for output to a display device.

24. The digital media content player of claim 17, wherein padding the first portion of the audiovisual data comprises adding one or more NULL packets to a transport stream.

25. The digital media content player of claim 17, wherein the media delivery system multiplexes an elementary audio stream and an elementary video stream to generate the plurality of portions of audiovisual data streamed to the content player.

18. A digital media content player configured to seamlessly switch a bit rate at which audiovisual data is streamed over a data communications network from a media delivery system to the digital media content player, the content player comprising:

a memory for storing a plurality of portions of the audiovisual data for decoding and playback by the content player; and

a processing unit coupled to the memory and configured to;

prior to initiating decoding and playback of the audiovisual data, configure a decoder on the content player to decode and playback the plurality of portions of the audiovisual data, wherein each portion is specified as having a size corresponding to an encoding of the portion at a first bit rate,

receive, over the data communications network, a first portion of the audiovisual data, wherein the first portion of the audiovisual data is encoded at a second bit rate, different from first bit rate specified for the first portion, and

pad the first portion of the audiovisual data such that the size of the first portion of the audiovisual data matches the specified size corresponding to the encoding of the portion of the audiovisual data encoded at the first bit rate.

19. The digital media content player of claim 18, wherein configuring the decoder on the content player to decode and playback the plurality of portions of the audiovisual data comprises:

receiving a plurality of file headers, each associated with a corresponding encoding of the audiovisual data, including a file header associated with an encoding of the audiovisual data at the first and second bit rates, wherein each file header specifies a size and a duration for each portion of the audiovisual data present in the corresponding encoding; and

generating, from the plurality of file headers, a playlist information file storing one or more clip information files, wherein each clip information file describes one of the portions of audiovisual data to be streamed from the media delivery system.

20. The digital media content player of claim 19, wherein each clip information file stores an indication of the largest encoded size, from the plurality of file headers, for one or more sequential portions of the audiovisual data.

21. The digital media content player of claim 19, wherein each clip information file indicates a sequence of one or more groups of pictures (GOPs) in the portion of the audiovisual data corresponding to a respective clip information file.

22. The digital media content player of claim 21, wherein padding the first portion of the audiovisual data comprises padding at least one GOP in the portion of the audiovisual data such that the size of each GOP matches the size specified in the respective clip information file.