core dump when extracting audio from flv file

[David Nielsen]

Binary package hint: mplayer

to reproduce:

1) sudo apt-get install mplayer yutube-dl
2) youtube-dl http://www.youtube.com/watch?v=UUMJTlKUA14
3) mplayer -dumpaudio UUMJTlKUA14.flv -dumpfile gimme.mp3

giving this

bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
bt_audio_service_open: connect() failed: Connection refused (111)
MPlayer UNKNOWN-4.4.3 (C) 2000-2009 MPlayer Team
mplayer: could not connect to socket
mplayer: No such file or directory
Failed to open LIRC support. You will not be able to use your remote control.

Playing UUMJTlKUA14.flv.
libavformat file format detected.
[lavf] Video stream found, -vid 0
[lavf] Audio stream found, -aid 1
VIDEO: [FLV1] 320x240 0bpp 30.000 fps 264.3 kbps (32.3 kbyte/s)
Core dumped ;)

Exiting... (End of file)

As this is the default install I understand if certain codecs aren't included for legal reasons but it would be nice if the application didn't crash and instead informed me that this was the problem.

ProblemType: Bug
Architecture: amd64
Date: Sat Mar 20 01:30:19 2010
DistroRelease: Ubuntu 10.04
InstallationMedia: Ubuntu 9.10 "Karmic Koala" - Release amd64 (20091027)
Package: mplayer 2:1.0~rc3+svn20090426-1ubuntu15
ProcEnviron:
 LANG=da_DK.utf8
 SHELL=/bin/bash
ProcVersionSignature: Ubuntu 2.6.32-16.25-generic
SourcePackage: mplayer
Uname: Linux 2.6.32-16-generic x86_64

[Reinhard Tartler (siretart)]

Thank you for taking the time to report this bug and helping to make Ubuntu better. Please try to obtain a backtrace following the instructions at http://wiki.ubuntu.com/DebuggingProgramCrash and upload the backtrace (as an attachment) to the bug report. This will greatly help us in tracking down your problem.

[Rolf Leggewie (r0lf)]

I can reproduce this slightly differently with "youtube-dl http://www.youtube.com/watch?v=tLxhuICUZbc && mplayer -dumpaudio tLxhuICUZbc.flv -dumpfile test.mp3"

[Rolf Leggewie (r0lf)]

I tried to get the backtrace, but running the program in gdb it exited normally. Seems to be timer-related?

[Robin Bowes (robinbowes)]

FWIW, I am seeing the same thing on Fedora 14 with mplayer-1.0-0.119.20100703svn.fc14.x86_64

[Axel Beckert (xtaran)]

JFTR: Same here on Debian Squeeze with 2:1.0~rc3++final.dfsg1-1.

[Axel Beckert (xtaran)]

Hmmm, according to http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=448761#14 this is no real core dump (as in "segfault"). mplayer tries to be funny when it saved the received (or to be encoded) file or stream as stream.dump.

In addition to that, the extraction of the audio stream from some video file or stream doesn't seem to be possible yet. Citing from http://www.mplayerhq.hu/DOCS/HTML/en/faq.html#id2946830 ...

Q: How do I encode only sound from a music video?

A: It's not possible directly, but you can try this (note the & at the end of mplayer command):

mkfifo encode
mplayer -ao pcm -aofile encode dvd://1 &
lame your_opts encode music.mp3
rm encode

This allows you to use any encoder, not only LAME, just replace lame with your favorite audio encoder in the above command.