Hi, I am running into a problem where newer versions of libav aren't able
to find the codecs for an mpeg-ts stream, from the /dev/dvb/adapter0/dvr0
device of a HDTV tuner tuned to ATSC. I can't find any version of ffplay
that will read directly from the device (even using "pipe:0") but if I cat
it to a file it will play with earlier versions. (this seems to be
related to the find_info function wanting to seek; I've worked around this
problem for now)
An earlier version of libav which uses liba52 will properly detect and
play the file, both audio and video.
The latest svn ffplay will not even detect that the file is mpeg-ts, even
if I force it with the -f parameter:
$ LD_LIBRARY_PATH=lib bin/ffplay -stats -debug 2 -f mpegts temp.mpegts
FFplay version SVN-r18970, Copyright (c) 2003-2009 Fabrice Bellard, et
al.
configuration: --enable-shared --disable-static
--prefix=/home/mconrad/buildenv --disable-optimizations --disable-mmx
--disable-stripping
libavutil 50. 3. 0 / 50. 3. 0
libavcodec 52.29. 1 / 52.29. 1
libavformat 52.33. 0 / 52.33. 0
libavdevice 52. 2. 0 / 52. 2. 0
libswscale 0. 7. 1 / 0. 7. 1
built on May 27 2009 18:25:07, gcc: 4.2.4 (Gentoo 4.2.4 p1.0)
temp.mpegts: could not find codec parameters
A version of ffplay from feburary will detect mpeg-ts and the video codec,
but not the audio:
FFplay version 0.5, Copyright (c) 2003-2009 Fabrice Bellard, et al.
configuration: --enable-shared --disable-static
--prefix=/home/mconrad/buildenv --disable-stripping
--disable-optimizations --disable-mmx
libavutil 49.15. 0 / 49.15. 0
libavcodec 52.20. 0 / 52.20. 0
libavformat 52.31. 0 / 52.31. 0
libavdevice 52. 1. 0 / 52. 1. 0
built on May 23 2009 22:49:56, gcc: 4.2.4 (Gentoo 4.2.4 p1.0)
Input #0, mpegts, from 'temp.mpegts':vq= 0KB sq= 0B
Duration: 00:00:07.50, start: 70329.129944, bitrate: 7411 kb/s
Stream #0.0[0x31], 1/90000: Video: mpeg2video, yuv420p, 1280x720
[PAR 1:1 DAR 16:9], 1001/120000, 19000 kb/s, 59.94 tbr, 90k tbn, 119.88 tbc
Stream #0.1[0x34], 1/90000: Audio: 0x0000, 48000 Hz, 5.1, s16, 384
kb/s
70332.36 A-V: 0.000 aq= 0KB vq= 1283KB sq= 0B
I saw that there was a new ac-3 decoder which replaced the dependence on
liba52, and that seems to have started the breakage.
I haven't tried initializing the codecs directly, because that seems
complicated, and I'd like it to work for any broadcast format and that
seems like a lot of work to manually detect it.
Does anyone know whether this is a known issue, and whether there is work
on fixing it?
If anyone wants an example file, I've got one at
http://silverdirk.com/dvbcapture.mpegts
Its an ~8 sec clip, 6MB. Plays with mplayer, but not with ffplay. Yes it
has errors in it, but mplayer can work around them, and the older ffplay
was at least able to play the video.
So this is a general query about mpeg-ts codec detection, but I'm also
interested in advice on how to fix the bug (i.e. which libav functions to
investigate), or if there are better ways to do dvb playback.
Thanks in advance!
--
Michael Conrad
IntelliTree Solutions llc.
513-552-6362
[email protected]
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