Robust system for maintaining audio/video synchronization during playback of multimedia streams with no embedded time stamps
An apparatus having a first circuit, a second circuit and a third circuit. The first circuit may be configured to (i) demultiplex a multimedia stream having one or more video and audio streams and (ii) generate one or more video signals and one or more audio data signals in response to demultiplexing the multimedia stream. The multimedia stream may be independent of embedded time stamps. The second circuit may be configured to (i) decode the one or more video data signals and the one or more audio data signals and (ii) generate a video current time signal for each decoded video signal and an audio current time signal for each decoded audio signal. The third circuit may be configured to synchronize the playback of each decoded audio signal and each decoded video signal with the video current time signal and the audio current time signal.
1. An apparatus comprising:
a first circuit configured to (i) demultiplex a multimedia stream having one or more video and audio streams and (ii) generate one or more video data signals and one or more audio data signals in response to demultiplexing said multimedia stream, wherein said multimedia stream is independent of embedded time stamps;
a second circuit configured to (i) decode said one or more video data signals and said one or more audio data signals and (ii) generate a video current time signal for each decoded video signal and an audio current time signal for each decoded audio signal, wherein said second circuit is configured to generate said audio current time signal based on a total time for each decoded audio signal, said video current time signal, and said video total time for each decoded video signal; and
a third circuit configured to synchronize the playback of each decoded audio signal and each decoded video signal with said audio current time signal and said video current time signal.
2. The apparatus according to claim 1 , wherein said second circuit comprises a video time circuit configured to determine said video current time signal based on a video frame rate and the number of frames for each decoded video signal.
3. The apparatus according to claim 2 , wherein said second circuit comprises an audio time circuit configured to determine a video total time for each decoded video signal based on the total number of frames and said frame rate.
4. The apparatus according to claim 1 , wherein said total time for each decoded audio signal is based on a total number of bytes and a bitrate of said decoded audio signal.
5. The apparatus according to claim 1 , wherein said total time for each decoded audio signal is based on a number of packets and a number of packets per second in each decoded audio signal.
6. The apparatus according to claim 1 , wherein said third circuit comprises an audio/video synchronization circuit configured to synchronize each decoded audio signal and each decoded video signal with said video current time signal for a predetermined amount of time while said second circuit generates said audio current time signal.
7. An apparatus comprising:
means for (i) demultiplexing a multimedia stream having one or more video and audio streams, wherein said multimedia stream is independent of embedded time stamps and (ii) generating one or more video data signals and one or more audio data signals in response to demultiplexing said multimedia stream wherein said multimedia stream is independent of embedded time stamps;
means for (i) decoding said one or more video data signals and one or more audio data signals, (ii) generating a video current time signal for each decoded video signal and an audio current time signal for each decoded audio signal, and (iii) generating said audio current time signal based on (a) a total time for each decoded audio signal, (b) said video current time signal, and (c) said video total time for each decoded video signal; and
means for synchronizing the playback of each decoded audio signal and each decoded video signal with said video current time signal and said audio current time signal.
8. A method for audio-video synchronization of a multimedia stream, comprising the steps of:
(A) demultiplexing said multimedia stream of data having one or more video and audio streams, wherein said multimedia stream is independent of embedded time stamps;
(B) generating one or more video data signals and one or more audio data signals in response to performing step (A);
(C) decoding said one or more video data signals and said one or more audio data signals;
(D) generating a video current time signal for each decoded video signal and an audio current time signal for each decoded audio signal;
(E) synchronizing the playback of each decoded audio signal and each video signal with said video current time signal and said audio current time signal; and
(F) generating said audio current time signal with a total time for each decoded audio signal, said video current time signal and said video total time.
9. The method according to claim 8 , wherein step (C) further comprises the step of:
generating said video current time signal with a video frame rate and the number of frames for each decoded video signal.
10. The method according to claim 9 , further comprising the step of:
determining a video total time for each decoded video signal based on the total number of frames and said frame rate of each decoded video signal.
11. The method according to claim 10 , further comprising the step of:
generating said audio current time signal based on a number of packets and the number of packets per second on each decoded audio signal.
12. The method according to claim 10 , further comprising the step of:
determining a video total time for each decoded video signal and an audio total time for each decoded audio signal after a predetermined amount of time.
13. The method according to claim 8 , wherein step (D) further comprises the step of:
synchronizing each decoded audio signal and each decoded video signal with said video current time signal for a predetermined amount of time while simultaneously generating said audio current time signal.
14. The method according to claim 8 , wherein step (A) further comprises the step of:
correctly maintaining the amount of time-difference between said video streams and said audio streams throughout an audio/video multiplex file.
15. The method according to claim 8 , wherein step (A) further comprises the step of:
maintaining a consistent relationship between audio packets in said audio stream and video packets in said video stream.
16. The method according to claim 15 , further comprising the step of:
maintaining a maximum distance between said audio packets and said video packets.
17. The method according to claim 8 , further comprising the step of:
multiplexing said multimedia stream at a known and constant frame-rate.
18. The method according to claim 8 , wherein step (A) further comprises the step of:
defining said audio stream as piecewise variable and as having a constant bit-rate over a maximum distance.