Ross,
Thanks for all the help so far!
So, I have a working AAC/H264 application and I'm very close to it
working just OK, except couple of glitches that needs to be settled.
Be sure to set "fPresentationTime" properly (in your "AACFramedSource" class) for each
AAC frame. To get proper audio/video sync in each media player client, this presentation time must be
properly aligned with the H.264 video presentation times, and with 'wall clock' time (i.e., the time that
you'd get by calling "gettimeofday()").
I implemented presentation timestamping like this:
1. There's one shared timeval start presentation time variable
(startPresentationTime ) between AACFramedSource and H264FramedSource.
Whichever gets its sample first, it will set the startPresentationTime
to gettimeofday.
2. After that, in each FramedSource (AAC/H264) fPresentationTime is set
like this:
unsigned uSeconds = PlayTimeOfTheSampleInMicroSeconds;
fPresentationTime.tv_sec = (uSeconds/1000000) +
m_presentationStartTime.tv_sec;
fPresentationTime.tv_usec = (uSeconds%1000000) +
m_presentationStartTime.tv_usec;
PlayTimeOfTheSampleInMicroSeconds I get from the AAC/H264 encoders,
respectively.
Is this a good setup?
When I run this, and preview it with VLC, it is kind of working, but
there are lots of frames and audio buffers dropped, and I get a lot of
warning messages, like this:
main warning: playback too late (177441): up-sampling
main warning: playback way too late (181443): flushing buffers
main warning: picture is too late to be displayed (missing 655 ms)
main warning: picture is too late to be displayed (missing 616 ms)
main warning: picture is too late to be displayed (missing 576 ms)
main warning: picture is too late to be displayed (missing 536 ms)
...
Why can this be happening?
I even tried to set the presentationStartTime to be 1 second ahead in
the future, but to no avail, i.e.:
gettimeofday(&m_presentationStartTime, NULL);
// Set it 1 sec into the future
m_presentationStartTime.tv_sec += 1;
Thanks,
Goran.
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