Hi, august wrote > >> One thing I noticed is that A/V sync is not perfect in the recorded >> files. >> Synchronizing 2 different streams from hardware devices is almost >> impossible. > > hmm. yeah. It is about 1 second off on my machine. How does skype and > other video software keep it in sync?
Hmm, off by one second is a bit much. What I do is to initialize the plugins for audio- and video recording. Then I fire up the 2 threads, which should start synchronously (i.e. much less than 1 sec apart from each other). Then the 2 threads read and encode samples/frames until I tell them to stop. Desync can happen because of the following (purely theoretical) issues: - If one A/V recorder plugin has some delay before the first sample or frame is read, it's out of my control. Video frames are less critical because they get timestamps from a software time. Audio streams are assumed to start at time zero though. - If your output format doesn't support variable framerates, things might get messed up. I always use mov with libquicktime for encoding. - If the encoding takes too long, theoretically only the framerate goes down, but in extreme cases A/V sync get messed up as well. No idea how other software handles this, and any input redarding that would be welcome. Unfortunately I don't have the Skype sourcecode here ;) > Maybe you succeed in reproducing the hang in gdb and make a backtrace of >> all threads. > > wasn't able to reproduce it. Me neither. There are some hangs, but only for a sec or so. Maybe it's because driver needs a bit more time to discuss with the hardware. Right now I'm in the UK behind the most paranoid firewall I've ever seen, so my developing capabilities are a bit limited... Burkhard ------------------------------------------------------------------------------ _______________________________________________ Gmerlin-general mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/gmerlin-general
