Methods and Apparatus for Generating a Transport Data Stream with Image Data

• US 20100085489A1
• Filed: 12/03/2008
• Published: 04/08/2010
• Est. Priority Date: 10/02/2008
• Status: Active Grant

• Current Assignee: Rohde & Schwarz GmbH & Company KG
• Original Assignee: Rohde & Schwarz GmbH & Company KG
• Inventors: Goerig, Torsten, Rusch-Ihwe, Jens, Hagemeier, Denis
• Granted Patent: US 8,532,188 B2
• Time in Patent Office: Days
• US Class Current: 348/723
• CPC Class Codes: H04N 19/114 Adapting the group of pictures [GOP] structure, e.g. number of B-frames between two anchor frames H04N19/107 takes 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 21/2343 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 21/236 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 21/2365 Multiplexing of several video streams
• CPC Class Codes: H04N 21/4347 Demultiplexing of several video streams
• CPC Class Codes: H04N 21/4384 involving operations to reduce the access time, e.g. fast-tuning for reducing channel switching latency
• 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 21/64315 DVB-H

Abstract

A transport data stream is generated by generating a data stream of successive second data frames with a GOP structure for each program containing image data of an image of an image sequence recorded digitally and belonging to the respective program by a source encoder. The transmission start, transmission period and transmission time are determined. At the start of first data frames, second data frames realized as P-frames or B-frames to be transmitted are replaced by second data frames realized as I-frames in each of the data streams belonging to a program and each first data frame of the transport data stream is packed with second data frames of data streams belonging in each case to one program whose transmission time fits the transmission start and the transmission period of the respective first data frame by means of a multiplexer.

Claims

1. A method for generating a transport data stream of successive first data frames including image data of a plurality of programs comprising:

generating a data stream of successive second data frames with a group of picture (GOP) structure for each program, each second data frame containing image data of an image of a digitally recorded image sequence belonging to a respective program, by one of a plurality of source encoders;

determining a transmission start and a transmission period of each first data frame of the transport data stream;

determining a transmission time of each second data frame of the data stream by allocating a respective second data frame to one of the first data frames of the transport data stream, by a respective one of the source encoders;

replacing second data frames realized as at least one of P-frames and B-frames and to be transmitted in their entirety at the start of first data frames by second data frames realized as I-frames in each of the data streams belonging to a respective program by the respective source encoder; and

packing each first data frame of the transport data stream with second data frames of data streams belonging in each case to a program and having a transmission time corresponding to the transmission start and the transmission period of the respective first data frame, by a multiplexer.

2. The method for generating the transport data stream according to claim 1, wherein the transmission start and the transmission period of each data frame of the transport data stream are determined in accordance with the Advanced Television Systems Committee-Mobile/Handheld Standard.

3. The method for generating the transport data stream according to claim 1, wherein the replacing of the second data frames occurs when the interval between the start of the first data frame and a next second data frame coming to lie in the same first data frame and realized as an I-frame is greater than a predetermined first minimal interval.

4. The method for generating the transport data stream according to claim 1, wherein second data frames realized as I-frames and that are not to be transmitted at the start of a first data frame are transmitted with a lower volume of data.

5. The method for generating the transport data stream according to claim 4, wherein second data frames realized as I-frames and not to be transmitted at the start of a first data frame are transmitted with a lower volume of data if the interval between the start of the first data frame and the second data frame realized as an I-frame is greater than a predetermined second minimal interval.

6. The method for generating the transport data stream according to claim 4, wherein a reduction of the data volume of the second data frames realized as I-frames and not to be transmitted at the start of the first data frame occurs by reducing a quantification of the image data belonging to the individual image points of the image transmitted in the second data frame realized as an I-frame.

7. The method for generating the transport data stream according to claim 1, wherein the number of second data frames in a GOP is increased to compensate for an increase of the data volume in the first data frame by replacing a second data frame realized at as least one of a P-frame and a B-frame with a second data frame realized as I-frame at the start of the first data frame.

8. The method for generating the transport data stream according to claim 1, wherein transmission times of the second data frames to be transmitted in an identical first data frame of the transport data stream are deposited by a respective source encoder as a reference mark in a first data packet of the second data frame of respective data streams transmitted at the start of an identical first data frame.

9. The method for generating a transport data stream according to claim 8, wherein the reference mark is a time stamp with an absolute point in time within a coordinated universal time.

10. The method for generating the transport data stream according to claim 8, wherein the reference mark is a time interval relative to an initialization time of the coordinated universal time or other reference point in time within the coordinated universal time.

11. The method for generating the transport data stream according to claim 10, wherein the time interval corresponds to the number of first data frames to be transmitted up to the transmission time of the respective first data frame, multiplied by a length in time of a first data frame.

12. The method for generating the transport data stream according to claim 1, wherein the transmission start and the transmission period of each first data frame of the transport data stream is determined by at least one of the source encoders.

13. The method for generating the transport data stream according to claim 12, wherein each of the plurality of source encoders receives a reference time from an allocated reference timer to determine the transmission time and the transmission period of each first data frame, the reference time being synchronized with the reference time of a reference timer allocated to the multiplexer.

14. The method for generating the transport data stream according to claim 12, wherein each source encoder receives, via the multiplexer, a reference time generated by a reference timer allocated to the multiplexer for the determination of the transmission time and the transmission period of each first data frame of the transport data stream.

15. The method for generating the transport data stream according to claim 1, wherein the transmission start and the transmission period of each first data frame of the transport data stream is determined and transmitted to each of the plurality of source encoders by the multiplexer.

16. The method for generating the transport data stream according to claim 1, wherein only a predetermined number of entire second data frames to be transmitted in a maximally available transmission capacity is packed into each first data frame.

17. The method for generating the transport data stream according to claim 1, wherein the second data frames of the respective data stream packed jointly into the first data frame of the transport data stream are completed by the respective source encoder at a generation time that precedes the transmission time of the second data frame to be transmitted at the start of the respective first data frame and the transmission time between the respective source encoder and the multiplexer, and is transmitted to the multiplexer.

18. The method for generating the transport data stream according to claim 17, wherein the generation time of the second data frames of the data stream to be packed into a respective first data frame of the transport data stream belonging to the respective program is determined by the respective source encoder.

19. The method for generating the transport data stream according to claim 17, wherein a generation time of the second data frames of the data stream to be packed into the respective first data frame of the transport data stream belonging to the respective program is determined by the multiplexer and transmitted to the respective source encoder.

20. An apparatus for generating a transport data stream of successive first data frames including image data of several programs, comprising:

at least one source encoder configured to generate a data stream with second data frames allocated to a program, each second data frame containing source-encoded image data of one image of an image sequence of the program; and

a downstream multiplexer and channel encoder configured to generate and channel code the data stream from the individual second data frames of the data stream allocated to a respective program.

21. An apparatus according to claim 20, wherein each one of the plurality of source encoders and the multiplexer are allocated respective reference timers synchronized with each other.

22. The apparatus according to claim 20, wherein the multiplexer is allocated a reference timer and the multiplexer is communicatively coupled to each one of the plurality of source encoders by at least one unidirectional data connection, each connection constructed to communicate the reference time.