[MPlayer-dev-eng] [PATCH] Fix for mpeg2 A/V sync bug.

[Steaphan Greene]

On 07/28/2011 05:52 PM, Ivan Kalvachev wrote:
> On 7/24/11, Reimar Döffinger <Reimar.Doeffinger at gmx.de> wrote:
>> I think you mentioned a case for which the time-stamp correction code
>> is necessary? I think that code is rather bad anyway: I never leads
>> to good timing, it can only convert completely wrong timing into
>> ok-timing as far as I understand and it should probably be restrained.
> 
> I'm also in favor of removing the ugly hack in mplayer.c .
> I think I tried to track down its introduction, at least in maillist
> and the case it "fixes" is double framerate of interlaced h264 .ts
> content. As the mail hinted, it is our demuxer that produces complete
> packets for single field (half frame), thus leading to double
> framerate.

Of course, I am also in favor of removing/restraining it.  That would
solve the problem for real.


>>> Without this patch, the current version of mplayer in SVN is not able to
>>> properly play most of my DVDs.  So, unless a better solution is obvious,
>>> I'd request this patch be applied.
>>
>> I tested about 10 different DVDs and not a single one has the slightest
>> issue.
>> I do not have any NTSC DVDs though.
>> Is there anyone else who can reproduce the issue?
> 
> It must be soft-telecine.
> Most Film->PAL is done by stretching the audio as the ratio is smaller (24->25).

Yes, this seems to cause problems with dvds where soft telecine is used
to up-convert from 24->30fps.  Basically, this is almost my entire DVD
collection, and probably most NTSC DVDs in the wild.

I have the opposite problem from you (Reimar).  I don't have any file
where this hack does any GOOD.  It just does nothing, or breaks stuff,
as far as I can tell from my testing.

The messages discussing the addition of this code discuss bad digital
transmissions being "corrected" by this.  If that's really the case,
perhaps this code should only be enabled with a command-line switch to
override the video pts, and, by default, should be skipped entirely?


Sorry for my delayed reply.  I was out of town for a bit, then spent a
few weeks fixing everything that went wrong at work while I was out of
town....

-- 
Steaphan Greene <sgreene at cs.binghamton.edu>
Lecturer, Computer Science, Binghamton University
GPG public key: http://www.cs.binghamton.edu/~sgreene/gpg.key.txt