Method and apparatus for audio and video synchronization timestamp rollover correction
View Patent ↗There are provided methods and apparatus for audio and video synchronization timestamp rollover correction. A synchronization apparatus includes a synchronizer for providing synchronization information for synchronizing a video stream with an audio stream during any point in a broadcast thereof irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps. The synchronization information is encoded for an out of band transmission with respect to the broadcast of the audio and video streams.
1. An apparatus comprising:
a synchronizer having a processor,
the synchronizer configured to provide synchronization information for synchronizing a video stream with an audio stream during a broadcast thereof using timestamps irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps and without utilization of additional video and audio streams,
wherein the synchronization information specifies a timing relationship between at least one audio timestamp and at least one video timestamp included in the audio stream and the video stream, respectively,
the synchronization information encoded for an out of band transmission with respect to the broadcast of the audio and video streams,
the timestamps including a video stream timestamp for the video stream and an audio stream timestamp for the audio stream,
the video stream timestamp and the audio stream timestamp being encoded for transmission.
2. The apparatus of claim 1 , further comprising a transmitter for transmitting the synchronization information to a receiving device in the out of band transmission.
3. The apparatus of claim 2 , wherein said synchronizer further provides an expiration time for the timestamps such that any given timestamp for either of the streams is only valid once within the expiration time, and said transmitter transmits the expiration time in the out of band transmission.
4. The apparatus of claim 1 , wherein the different rollover points relate to different clocks or different clock multipliers.
5. The apparatus of claim 1 , wherein the synchronization information enables the video stream to be synchronized with the audio stream any time before and after a first timestamp rollover relating to any of the streams.
6. The apparatus of claim 1 , wherein the synchronization information is provided in a data structure that signals at least one of the audio stream and the video stream.
7. The synchronization apparatus of claim 1 , wherein the synchronization information is specified in metadata.
8. The apparatus of claim 1 , wherein the synchronization information is specified using Session Description Protocol.
9. A synchronization method, comprising:
providing, using a processor,
synchronization information for synchronizing a video stream with an audio stream during a broadcast thereof using timestamps irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps and without utilization of additional video and audio streams,
wherein the synchronization information specifies a timing relationship between at least one audio time stamp and at least one video timestamp included in the audio stream and the video stream, respectively,
the synchronization information encoded for an out of band transmission with respect to the broadcast of the audio and video streams,
the timestamps including a video stream timestamp for the video stream and an audio stream timestamp for the audio stream,
the video stream timestamp and the audio stream timestamp being encoded for transmission.
10. The method of claim 9 , further comprising transmitting the synchronization information to a receiving device in the out of band transmission.
11. The method of claim 10 , further comprising: providing an expiration time for the timestamps such that any given timestamp for either of the streams is only valid once within the expiration time; and transmitting the expiration time to the receiving device in the out of band transmission.
12. The method of claim 9 , wherein the different rollover points relate to different clocks or different clock multipliers.
13. The method of claim 9 , wherein the synchronization information enables the video stream to be synchronized with the audio stream any time before and after a first timestamp rollover relating to any of the streams.
14. The method of claim 9 , wherein the synchronization information is provided in a data structure that signals at least one of the audio stream and the video stream.
15. The method of claim 9 , wherein the synchronization information is specified in metadata.
16. The method of claim 9 , wherein the synchronization information is specified using Session Description Protocol.
17. An apparatus, comprising:
a synchronizer having a processor,
the synchronizer configured to synchronize a video stream and an audio stream using synchronization information received in an out of band transmission with respect to a broadcast of the video stream and the audio stream,
wherein the synchronization information specifies a timing relationship between at least one audio time stamp and at least one video timestamp included in the audio stream and the video stream, respectively,
wherein the synchronizer is adapted to use the synchronization information to synchronize the video stream and the audio stream of the broadcast
using timestamps irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps and without utilization of additional video and audio streams,
the timestamps including a video stream timestamp for the video stream and an audio stream timestamp for the audio stream,
the video stream timestamp and the audio stream timestamp generated remotely and received in a transmission.
18. The apparatus of claim 17 , further comprising a receiver for receiving the synchronization information from a sending device in the out of band transmission.
19. The apparatus of claim 18 , wherein said receiver receives an expiration time from the sending device in the out of band transmission, and said synchronizer applies the expiration time to the timestamps of the streams such that any given timestamp for either of the streams is only valid once within the expiration time.
20. The apparatus of claim 17 , wherein the different rollover points relate to different clocks or different clock multipliers.
21. The apparatus of claim 17 , wherein the synchronization information enables the video stream to be synchronized with the audio stream any time before and after a first timestamp rollover relating to any of the streams.
22. The apparatus of claim 17 , wherein the synchronization information is provided in a data structure that signals at least one of the audio stream and the video stream.
23. The apparatus of claim 17 , wherein the synchronization information is specified in metadata.
24. The apparatus of claim 17 , wherein the synchronization information is specified using Session Description Protocol.
25. A synchronization method, comprising:
synchronizing, using a processor,
a video stream and an audio stream using synchronization information received in an out of band transmission with respect to a broadcast of the video stream and the audio stream,
wherein the synchronization information specifies a timing relationship between at least one audio time stamp and at least one video timestamp included in the audio stream and the video stream, respectively, and
wherein the synchronization information is adapted to synchronize the video stream and the audio stream of the broadcast using timestamps,
irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps and without utilization of additional video and audio streams,
the timestamps including a video stream timestamp for the video stream and an audio stream timestamp for the audio stream,
the video stream timestamp and the audio stream timestamp generated remotely and received in a transmission.
26. The method of claim 25 , further comprising receiving the synchronization information from a sending device in the out of band transmission.
27. The method of claim 26 , further comprising: receiving an expiration time from the sending device in the out of band transmission, the expiration time for applying to the timestamps of the streams such that any given timestamp for either of the streams is only valid once within the expiration time.
28. The method of claim 25 , wherein the different rollover points relate to different clocks or different clock multipliers.
29. The method of claim 25 , wherein the synchronization information enables the video stream to be synchronized with the audio stream any time before and after a first timestamp rollover relating to any of the streams.
30. The method of claim 25 , wherein the synchronization information is provided in a data structure that signals at least one of the audio stream and the video stream.
31. The method of claim 25 , wherein the synchronization information is specified in metadata.
32. The method of claim 25 , wherein the synchronization information is specified using Session Description Protocol.
33. A non-transitory storage media having information stored thereon, comprising:
synchronization information for synchronizing a video stream with an audio stream during a broadcast thereof
using timestamps irrespective of whether the video stream and the audio stream have different rollover points for their respective timestamps and without utilization of additional video and audio streams,
wherein the synchronization information specifies a timing relationship between at least one audio time stamp and at least one video timestamp included in the audio stream and the video stream, respectively,
the synchronization information encoded for an out of band transmission with respect to the broadcast of the audio and video streams,
the timestamps including a video stream timestamp for the video stream and an audio stream timestamp for the audio stream,
the video stream timestamp and the audio stream timestamp being encoded for transmission.