[MPlayer-dev-eng] [PATCH] bframes, dwStart: individual patches

[Corey Hickey]

Oded Shimon wrote:
>>>>These patches have been sitting around in combined form for a while,
>>>>minus a couple bugfixes, and the only comments are good (thanks to
>>>>Guillaume for testing). The changes are diverse, though, so I'm not
>>>>going to apply them all at once; instead, I will commit each patch, in
>>>>order, no less than 24 hours after the previous one... starting no less
>>>>than 24 hours from now.
>>>
>>>
>>>If you want, I can test the combined form (since it contains some bug
>>>fixes, it may be interesting to test again), as what really interests
>>>me is the effect of patch 4.
>>>
>>>As far as patches 01-03 are concerned, I don't quite know what to look
>>>for, and/or I think that my regular use of MPlayer/MEncoder do not
>>>make me run code paths that your other patches touch.
>>
>>Here is a set of several tests, if you feel like doing them.
> 
> 
> Have you tested 'mencoder -delay'? both posotive and negative. It's a 
> completely different set of code, it might interfeer.

I did early on, and I checked again now -- they don't seem to have a
problem with each other. The effects of each option are independent of
each other when encoding, and have a cumulative effect on playback. For
example, here are a couple examples of the two options canceling each
other out.

$ mencoder orig.avi -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=800 \
-oac copy -o test.avi -delay -10 -audio-delay -10

-delay cuts off the first 10 seconds of the video, and -audio-delay
delays the video from playing until after the first 10 seconds of audio
-- resulting in the remainder being in sync.


Similarly:
$ ... -delay 10 -audio-delay 10

-delay 10 cuts off the first part of the audio (and mencoder also has to
duplicate several frames); -audio-delay 10 makes mplayer play the video
quickly at first to catch up -- resulting, as well, in the remainder of
the movie being in sync.


Re-encoding a dwStart video with -delay will have the same effect, since
dwStarts are applied in the same manner as -audio-delay. If this is
undesirable, -ignore-start can be used.

Of course, the examples above have no practical use, but they
demonstrate that neither option interferes with the other.

-Corey