[vdr] vdr-1.6.0 and syncearly
rnissl at gmx.de
Tue Apr 1 18:46:39 CEST 2008
Dominique Simon schrieb:
>> I'd say it's suggested. At least it is part of my H.264 patches.
> What does the sync early patch do?
Vanilla VDR waits for an I frame before it passes video (and
audio) data on to output devices. Further more, audio data is
still not passed on from that time, because VDR takes some time
to decide which audio track shall get selected.
The sync early patch addresses these issues. Audio and video
packets are passed on a soon as they make up a valid frame. The
result is that you can already hear the audio track before the
video appears on screen. This is because video decoding can only
start with an I frame. Any frames before the I frame won't appear
But passing these frames to the output device has the benefit
that PTS' (presentation time stamp) for these frames are passed
on to the output device which needs this information to
synchronize audio and video. As a result, audio and video will be
in sync already when the first image appears on screen.
That's why the patch got called "sync early".
Dipl.-Inform. (FH) Reinhard Nissl
mailto:rnissl at gmx.de
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