[MPlayer-users] lavf demuxer

[The Wanderer]

On 12/13/2005 02:56 PM, Ryan Olf wrote:

> On Tuesday 13 December 2005 09:07 am, The Wanderer wrote:
> 
>> (quoting reordered for my sanity's sake)
>> 
>> Please don't top-post.

Bottom-posting, while better, is still not ideal. Interleaved posting,
as most people on these lists do, is much to be preferred.

>> Ryan Olf wrote:

>>> Yeah, *thanks*. I thought that maybe a simple question could get
>>> a simple answer, or at least AN answer. I posted a few days ago
>>> with the subject: lavf demuxer 64bit problem? including all the
>>> relevant information, and got no replies, so I thought I'd try
>>> something simple, coax average joe user into revealing his/her
>>> experience. I thought, maybe all the details turned people away.
>>> If you want the details, you can see that email in the archives:
>>> 
>>> http://archives.free.net.ph/message/20051210.105528.7c873386.en.html
>> 
>> For what it's worth, the reason I didn't respond to that message is
>> because I don't have a 64-bit system and so am not in a position
>> to so much as test it, much less try to do anything about it. I
>> imagine the same is true of quite a number of others, as well.
>> 
>> I've just grabbed the first of the two files you linked to in the
>> above-referenced post, however, and it is likewise played at 90000
>> fps even on my own 32-bit system. This is (probably) not a
>> libavformat problem, however; the file is played back at the
>> correct speed by ffplay, which is FFmpeg's internal bare-bones
>> media player and obviously uses libavformat for demuxing. Unless
>> the bug was introduced into libavformat in the time since I last
>> updated ffplay - i.e., since the 9th of this month - it must in
>> fact lie somewhere else.
>> 
>> 'mplayer -identify' reports the file as having a frame rate of
>> 90000 fps, so it's not surprising that it is played back at that
>> rate. ffmpeg itself reports the file as having a frame rate of
>> 29.97 (-> 30000/1001) fps. The bug is somewhere in MPlayer - at a
>> first guess, somewhere in demux_lavf.c.
>> 
>> I would guess, in the absence of further information, that the
>> difference between the 64-bit and 32-bit versions you ran was that
>> they were built on different versions of the source tree - not
>> actually compiled from the same source. Obtaining and compiling the
>> source of the version which gave you correct playback would
>> probably let you play the file normally. In any case, knowing the
>> exact version string of that copy of MPlayer would probably help
>> narrow down the change which caused the problem.
> 
> So the framerate issue is a bug in the newer CVS versions?  The
> file.ts plays just fine under MPlayer 1.0pre7try2-3.4.4, but gives
> insane framerate values for MPlayer dev-CVS-051130-13:28-3.4.4.

Sorry about the delay - I have a tendency to procrastinate sometimes.

Those versions are ridiculously far apart - more than a year, unless my
memory is playing tricks on me. The only meaningful comparison is
between different CVS versions.

> What about file2.ts?  It won't play under any versions of mplayer
> (with lavf demuxer) that I have, 32bit or otherwise.  It plays under
> default demuxer.

That *could*, in fact, be a bug in libavformat itself. For me, likewise,
the file plays just fine with 'mplayer', but fails out of 'mplayer
-demuxer 35' with "LAVF_header: av_open_input_stream() failed". ffplay
exits with 'file2.ts: Error while opening file'. In the former case,
tracking down where the message involved is printed would probably be
helpful in figuring out where the bug is, but I'm currently recompiling
so I can't easily do so at the moment.

Weirdly, 'mplayer -identify' on either of these two TS files produces a
flood of "ID_VIDEO_ID=" lines (and eventually a crash, in at least one
case), but 'mplayer -identify -demuxer 35' produces normal identify
output (albeit with the incorrect framerate). I have no idea whether or
not this is related.

-- 
       The Wanderer

Warning: Simply because I argue an issue does not mean I agree with any
side of it.

Secrecy is the beginning of tyranny.