ADAPTIVE SYNCHRONIZATION WITH LIVE MEDIA STREAM

• US 20200137433A1
• Filed: 10/26/2018
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: BUDD, Colin, KATZ, Alexander Jacob
• Granted Patent: US 10,805,651 B2
• Time in Patent Office: Days
• CPC Class Codes: H04N 21/2187 Live feed
• CPC Class Codes: H04N 21/23106 involving caching operations prefetching while addressing of a memory level in which the access to the desired data or data block requires associative addressing means within memory systems or architectures G06F12/0862; caching at an intermediate stage in a data network H04L67/568
• CPC Class Codes: H04N 21/234381 by altering the temporal resolution, e.g. decreasing the frame rate by frame skipping
• CPC Class Codes: H04N 21/23805 Controlling the feeding rate to the network, e.g. by controlling the video pump
• CPC Class Codes: H04N 21/2387 Stream processing in response to a playback request from an end-user, e.g. for trick-play
• 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 21/26283 for associating distribution time parameters to content, e.g. to generate electronic program guide data
• CPC Class Codes: H04N 21/26616 for merging a unicast channel into a multicast channel, e.g. in a VOD application, when a client served by unicast channel catches up a multicast channel to save bandwidth data multicast over packet-switching network H04L12/18
• CPC Class Codes: H04N 21/2747 Remote storage of video programs received via the downstream path, e.g. from the server
• CPC Class Codes: H04N 21/4147 PVR [Personal Video Recorder] H04N5/76 takes precedence ; arrangements for broadcast with accumulation-type receivers H04H20/40
• 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 21/440281 by altering the temporal resolution, e.g. by frame skipping television signal recording using magnetic recording on tape for reproducing at a rate different from the recording rate H04N5/783
• CPC Class Codes: H04N 21/47217 for controlling playback functions for recorded or on-demand content, e.g. using progress bars, mode or play-point indicators or bookmarks specific graphical features in visual interfaces H04N21/4312
• CPC Class Codes: H04N 21/6547 comprising parameters, e.g. for client setup
• CPC Class Codes: H04N 21/6587 Control parameters, e.g. trick play commands, viewpoint selection

Abstract

In synchronizing a playback of recorded media with a live media stream, a server streams live media to each of a plurality of participant devices at a normal rate. The live media stream is recorded and stored as the recorded media stream. When the server receives, from a given participant device of the plurality of participant devices, a request for playback after a pause at or a rewind to a specified location in the live media stream, the server calculates a playback rate to play the recorded media stream starting at the specified location. The playback rate is calculated such that a playback of the recorded media stream synchronizes with the live media stream at a target location or at a target time. The recorded media stream is then caused to play at the given participant device at the playback rate starting at the specified location.

Claims

1. A method for synchronizing a playback of recorded media with a live media stream, comprising:

streaming, by a server, live media to each of a plurality of participant devices at a normal rate;

recording the live media stream and storing the recorded media stream;

receiving, by the server from a given participant device of the plurality of participant devices, a request for playback after a pause at or a rewind to a specified location in the live media stream;

in response, calculating a playback rate to play the recorded media stream starting at, the specified location, wherein a playback of the recorded media stream synchronizes with the live media stream at a target location or at a target time; and

causing the recorded media stream to play at the given participant device at the playback rate starting at the specified location.

2. The method of claim 1, wherein the calculating of the playback rate comprises:

calculating an estimated remaining time of the live media stream to reach the target location or the target time (X);

calculating an estimate remaining time of the recorded media stream to reach the target location or the target time (Y);

calculating a playback rate factor as X/Y; and

calculating the playback rate as a product of the playback rate factor and the normal rate.

3. The method of claim 2, further comprising:

during the live media stream, updating X;

updating the playback rate based on the updated X; and

causing unplayed portions of the recorded media stream to play at the given participant device at the updated playback rate.

4. The method of claim 1, further comprising:

during the playing of the recorded media stream, receiving a request for playback after a pause at or a rewind to a second specified location in the recorded media stream;

in response, recalculating the playback rate for the recorded media stream, wherein the playback of the recorded media stream starting at the second specified location is synchronized with the live media stream at the target location or at the target time; and

causing the recorded media stream to play at the given participant de ice at the recalculated playback rate starting at the second specified location.

5. The method of claim 1, wherein the calculating of the playback rate and the playing of the recoded media stream comprise:

removing non-essential segments from the recorded media stream to form a truncated recorded media stream;

calculating the playback rate to play the truncated recorded media stream, where the playback of the truncated recorded media stream synchronizes with the live media stream at the target location or at the target time; and

causing the truncated recorded media stream to play at the given participant device at the playback rate starting at the specified location.

6. The method of claim 1, further comprising:

receiving, by the server from a second participant device of the plurality of participant devices, a second request for playback after a pause at or a rewind to a second specified location in the live media stream;

in response, calculating a second playback rate to play a second copy of the recorded media stream starting at the second specified location, wherein a playback of the second copy of the recorded media stream synchronizes with the live media stream at a second target location or at a second target time; and

causing the second copy of the recorded media stream to play at the second participant device at the second playback rate starting at the second specified location,

wherein the calculating of the second playback rate and the playing of the second copy of the recorded media stream are performed independently of the calculating of the playback rate and the playing of the recorded media stream in response to the request from the given participant device.

7. The method of claim 1, wherein two or more participant devices of the plurality of participant devices each records a copy of the live media stream, stores a corresponding recorded media stream at a corresponding local storage, and plays the corresponding recorded media stream at a corresponding playback rate.

8. A computer program product for synchronizing a playback of recorded media with a live media stream, the computer program product comprising a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to:

stream live media to each of a plurality of participant devices at a normal rate;

record the live media stream and storing the recorded, media stream;

receive from a given participant device of the plurality of participant devices a request for playback after a pause at or a rewind to a specified location in the live media stream;

in response, calculate a playback rate to play the recorded media stream starting at the specified location, wherein a playback of the recorded media stream synchronizes with the live media stream at a target location or at a target time; and

cause the recorded media stream to play at the given participant device at the playback rate starting at the specified location.

9. The computer program product of claim 8, wherein in the calculating of the playback rate, the processor is further caused to:

calculate an estimated, remaining time of the live media stream to reach the target location or the target time (X);

calculate an estimate remaining time of the recorded media stream to reach the target location or the target time (Y);

calculate a playback rate factor as X/Y; and

calculate the playback rate as a product of the playback rate factor and the normal rate.

10. The computer program product of claim 9, wherein the processor is further caused to:

during the live media stream, update X;

update the playback rate based on the updated X; and

cause unplayed portions of the recorded media stream to play at the given participant device at the updated playback rate.

11. The computer program product of claim 8, wherein the processor is further caused to:

during the playing of the recorded media stream, receive a request for playback after a pause at or a rewind to a second specified location in the recorded media stream;

in response, recalculate the playback rate for the recorded media stream, wherein the playback of the recorded media stream starting at the second specified location is synchronized with the live media stream at the target location or at the target time; and

cause the recorded media stream to play at the given participant device at the recalculated playback rate starting at the second specified location.

12. The computer program product of claim 8, wherein the calculating of the playback rate and the playing of the recoded media stream comprise:

remove non-essential segments from the recorded media stream to form a truncated recorded media stream;

calculate the playback rate to play the truncated recorded media stream, where the playback of the truncated recorded media stream synchronizes with the live media stream at the target location or at the target time; and

cause the truncated recorded media stream to play at the given participant device at the playback rate starting at the specified location.

13. The commuter program product of claim 8, wherein the processor is further cause to:

receive, from a second participant device of the plurality of participant devices, a second request for playback after a pause at or a rewind to a second specified location in the live media stream;

in response, calculate a second playback rate to play a second copy of the recorded media stream starting at the second specified location, wherein a playback of the second copy of the recorded media stream synchronizes with the live media stream at a second target location or at a second target time; and

cause the second copy of the recorded media stream to play at the second participant device at the second playback rate starting, at the second specified location,

wherein the calculating of the second playback rate and the playing of the second copy of the recorded media stream are performed independently of the calculating of the playback rate and the playing of the recorded media stream in response to the request from the given participant device.

14. The computer program product of claim 8, wherein two or more participant devices of the plurality of participant devices each records a copy of the live media stream, stores a corresponding recorded media stream at a corresponding local storage, and plays the corresponding recorded media stream at a corresponding playback rate.

15. A system, comprising:

a processor; and

a computer readable storage medium having program instructions embodied therewith, the program instructions executable by a processor to cause the processor to;

stream live media to each of a plurality of participant devices at a normal, rate;

record the live media, stream and storing, the recorded media stream;

receive from a given participant device of the plurality of participant devices a request for playback after a pause at or a rewind to a specified location in the live media stream;

in response, calculate a playback rate to play the recorded media stream starting at the specified location, wherein a playback of the recorded media stream synchronizes with the live media stream at a target location or at a target time; and

cause the recorded media stream to play at the given participant device at the playback rate starting at the specified location.

16. The system of claim 15, wherein in the calculating of the playback rate, the processor is further caused to:

calculate an estimated remaining time of the live media stream to reach the target location or the target time (X);

calculate an estimate remaining time of the recorded media stream to reach the target location or the target time (Y);

calculate a playback rate factor as X/Y; and

calculate the playback rate as a product of the playback rate factor and the normal rate.

17. The system of claim 16, wherein the processor is further caused to:

during the live media stream, update X;

update the playback rate based on the updated X; and

cause unplayed portions of the recorded media stream to play at the given participant device at the updated playback rate.

18. The system of claim 15, wherein the processor is further caused to:

during the playing of the recorded media stream, receive a request for playback after a pause at or a rewind to a second specified location in the recorded media stream;

in response, recalculate the playback rate for the recorded media stream, wherein the playback of the recorded media stream starting at the second specified location is synchronized with the live media stream at the target location or at the target time; and

cause the recorded media stream to play at the <

given participant device at the recalculated playback rate starting at the second specified location.

19. The system of claim 15, wherein the calculating of the playback rate and the playing of the recoded media stream comprise:

remove non-essential segments from the recorded media stream to form a truncated recorded media stream;

calculate the playback rate to play the truncated recorded media stream, where the playback of the truncated recorded media, stream synchronizes with the live media stream at the target location or at the target time; and

cause the truncated recorded media stream to play at the given participant device at the playback rate starting at the specified location.

20. The system of claim 15, wherein the processor is further cause to:

receive, from a second participant device of the plurality of participant, devices, a second request for playback after a pause at or a rewind to a second specified location in the live media stream;

in response, calculate a second playback rate to play a second copy of the recorded media stream starting at the second specified location, wherein a playback of the second copy of the recorded media stream synchronizes with the live media stream at a second target location or at a second target time; and

cause the second copy of the recorded media stream to play at the second participant device at the second playback rate starting at the second specified location,

wherein the calculating of the second playback rate and the playing of the second copy of the recorded media stream are performed independently of the calculating of the playback rate and the playing of the recorded media stream in response to the request from the given participant device.