Preserving Captioning Through Video Transcoding

• US 20110164673A1
• Filed: 08/07/2008
• Published: 07/07/2011
• Est. Priority Date: 08/09/2007
• Status: Active Grant

• Current Assignee: Triton US VP Acquisition, Co.
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Shaffer, Gary
• Granted Patent: US 9,426,479 B2
• Time in Patent Office: Days
• US Class Current: 375/240.01
• 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 21/233 Processing of audio elementary streams monitoring, identification or recognition of audio in broadcast systems H04H60/58
• CPC Class Codes: H04N 21/2335 involving reformatting operations of audio signals, e.g. by converting from one coding standard to another details of audio signal transcoding G10L19/173
• CPC Class Codes: H04N 21/234 Processing of video elementary streams, e.g. splicing of video streams or manipulating encoded video stream scene graphs
• CPC Class Codes: H04N 21/2343 involving reformatting operations of video signals for distribution or compliance with end-user requests or end-user device requirements video transcoding H04N19/40; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/234309 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 or from Quicktime to Realvideo conversion of standards in analog television systems H04N7/01
• CPC Class Codes: H04N 21/235 Processing of additional data, e.g. scrambling of additional data or processing content descriptors
• CPC Class Codes: H04N 21/2355 involving reformatting operations of additional data, e.g. HTML pages optimising the visualization of content for information retrieval from the Internet G06F16/9577; tracking of instant messages H04L51/234; media packet handling at the source H04L65/762
• CPC Class Codes: H04N 21/236 Assembling of a multiplex stream, e.g. transport stream, by combining a video stream with other content or additional data, e.g. inserting a URL [Uniform Resource Locator] into a video stream, multiplexing software data into a video stream; Remultiplexing of multiplex streams; Insertion of stuffing bits into the multiplex stream, e.g. to obtain a constant bit-rate; Assembling of a packetised elementary stream multiplexing of data packets for data networks, e.g. RTP/UDP H04L65/00
• CPC Class Codes: H04N 21/2362 Generation or processing of Service Information [SI]
• CPC Class Codes: H04N 21/242 Synchronization processes, e.g. processing of PCR [Program Clock References] arrangements for synchronising broadcast or distribution via plural systems in broadcast distribution systems H04H20/18
• CPC Class Codes: H04N 21/440218 by transcoding between formats or standards, e.g. from MPEG-2 to MPEG-4 conversion of standards in analogue television systems H04N7/01
• CPC Class Codes: H04N 21/4884 for displaying subtitles
• CPC Class Codes: H04N 5/278 Subtitling
• CPC Class Codes: H04N 7/0885 for the transmission of subtitles

Abstract

Methods of preserving captioning information in an input video stream through transcoding of the input video stream include extracting caption data from the input video stream, translating the caption data into at least one output caption format, packaging the translated caption data into data packets for insertion into a video stream, synchronizing the packaged caption data with a transcoded version of the input video stream, receiving a preliminary output video stream that is a transcoded version of the input video stream, and combining the packaged caption data with the preliminary output video stream to form an output video stream. Related systems and computer program products are also disclosed.

Claims

1. A method of preserving captioning information in an input video stream through transcoding of the input video stream, the method comprising:

extracting caption data related to the input video stream;

translating the caption data into at least one output caption format;

packaging the translated caption data into data packets;

synchronizing the packaged caption data with a transcoded version of the input video stream;

receiving a preliminary output video stream that is a transcoded version of the input video stream; and

combining the packaged and synchronized caption data with the preliminary output video stream to form an output video stream.

2. The method of claim 1, wherein extracting caption data comprises reading caption data from a caption data file.

3. The method of claim 1, wherein the output caption format is the same as an input caption format.

4. The method of claim 1, wherein combining the packaged and synchronized caption data with the preliminary output video stream comprises generating a caption data file that is associated with the preliminary output video stream.

5. The method of claim 1, further comprising detecting caption data underflow or overflow in the extracted caption data, and compensating for caption data underflow or overflow in the extracted caption data.

6. The method of claim 5, wherein compensating for caption data underflow or overflow in the extracted caption data comprises adding null data to the caption data in the case of caption data underflow and deleting null data in the caption data in the case of caption data overflow.

7. The method of claim 1, further comprising correcting information and/or coding errors in the extracted caption data.

8. The method of claim 1, further comprising converting the extracted caption data into an intermediate format before translating the extracted caption data, wherein translating the extracted caption data comprises translating the extracted caption data from the intermediate format into the at least one output captioning format.

9. The method of claim 1, further comprising buffering the extracted caption data before packaging the extracted caption data.

10. The method of claim 1, further comprising parsing the input video stream to determine a presentation order of encoded frames in the input video stream;

and reordering the caption data into the presentation order of encoded frames in the input video stream before translating the caption data.

11. The method of claim 10, wherein parsing the input video stream comprises assigning time stamps to the caption data.

12. The method of claim 1, further comprising parsing the preliminary output video stream to determine a coded order of encoded frames in the preliminary output video stream;

and reordering the packaged caption data into the coded order of encoded frames in the preliminary output video stream before combining the packaged caption data with the preliminary output video stream.

13. The method of claim 1, further comprising transmitting a target encoding bit rate to a video encoding module in response to an amount of extracted or expected caption data.

14. The method of claim 1, wherein combining the translated caption data with the preliminary output video stream comprises inserting the packaged and synchronized caption data into spaces reserved in the preliminary output video stream.

15. A system for preserving captioning information in an input video stream through transcoding of the input video stream, the system comprising:

a caption extraction module configured to extract caption data from the input video stream;

a caption processing module configured to translate the extracted caption data into at least one output caption format; and

a caption packaging module configured to synchronize the translated caption data with a preliminary output video stream that is a transcoded version of the input video stream.

16. The system of claim 15, further comprising a plurality of input queues corresponding to respective caption formats, wherein the caption extraction module is configured to store the caption data in one or more of the input queues and wherein the caption packaging module is configured to retrieve caption data for packaging from the input queues.

17. The system of claim 15, wherein the caption extraction module is configured to compute an amount of caption data to be packaged by the caption packaging module to avoid caption data overflow.

18. The system of claim 15, wherein the caption packaging module is configured to organize the translated caption data into caption data packets that are to be inserted into the preliminary output video stream.

19. The system of claim 15, further comprising a caption input reorder queue that is configured to reorder the extracted caption data into a presentation order of the input video stream to accommodate a possible difference between presentation and coding order of the input video stream.

20. The system of claim 15, further comprising a caption output reorder queue that is configured to reorder the packaged caption data into a coding order of the preliminary output video stream.

21. The system of claim 15, further comprising a caption/video combining module that is configured to insert the packaged caption data into the preliminary output video stream to form an output video stream.

22. The system of claim 21, wherein the caption packaging module is configured to provide a target bit rate to a video processing module based on an amount of caption data to be inserted into the preliminary output video stream.

23. The system of claim 21, wherein the caption packaging module is configured to obtain frame ordering and/or timing information for the preliminary output video stream from a video processing module that performs transcoding of the input video stream.

24. A system for preserving captioning information in an input video stream through transcoding of the input video stream, the system comprising:

a caption extraction module configured to extract caption data from the input video stream;

a caption processing module configured to translate the extracted caption data into at least one output caption format; and

a caption packaging module configured to generate packaged caption data for insertion into an output video stream and to provide the packaged caption data to a video processing module that transcodes the input video stream.

25. A computer program product for preserving captioning information in an input video stream through transcoding of the input video stream, the computer program product comprising:

a computer readable storage medium having computer readable program code embodied in the medium, the computer readable program code comprising;

computer readable program code configured to extract caption data from the input video stream;

computer readable program code configured to translate the caption data into at least one output caption format;

computer readable program code configured to package the translated caption data into data packets for insertion into a video stream;

computer readable program code configured to synchronize the packaged caption data with a transcoded version of the input video stream;

computer readable program code configured to receive a preliminary output video stream that is a transcoded version of the input video stream; and

computer readable program code configured to combine the packaged and synchronized caption data with the preliminary output video stream to form an output video stream.