[MPlayer-dev-eng] [PATCH]: Fallback to null video codec

[Filip Kalinski]

On Fri, Jan 10, 2003 at 01:52:53PM +0100, Arpi wrote:
> Hi,
> 
> > Some time ago I was complaining about crashing of mplayer when:
> 
> when?

That was: "[BUG] Audio only playing burns CPU" thread.

> >  if(!sh_video->inited){
> >      mp_msg(MSGT_DECVIDEO,MSGL_HINT, MSGTR_TryUpgradeCodecsConfOrRTFM
> > ,get_path("codecs.conf"));
> >      mp_msg(MSGT_DECVIDEO,MSGL_ERR,MSGTR_CantFindVideoCodec,sh_video->format);
> > +    // fall back to null when codec is not found
> > +    init_video(sh_video,"null",NULL,-1);
> >      return 0; // failed
> >  }
> 
> no, this is wrong.
> look at that return 0;
> 
> mplayer should not play (not even demux) video at all, if the
> codec init failed.
> 
> what fileformat and -vo driver you used for reproducing this bug?
> don't say any, i cannot reproduce it here.
> 

Take a mpeg-ps file, run "mplayer <file> -vc foobar -vo null" and press
an arrow key to do the seek. It gets segmentation fault (because there
is no video demuxer).

For example:

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GDB is free software, covered by the GNU General Public License, and you are
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Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "--host= --target=athlon-pld-linux"...
(gdb) run ~/movies/Megaus.mpg -vc foobar -vo null
Starting program: /mnt/data/work/mplayer/main.dev/mplayer ~/movies/Megaus.mpg -vc foobar -vo null
[New Thread 8192 (LWP 8379)]
Using GNU internationalization
Original domain: messages
Original dirname: /usr/share/locale
Current domain: mplayer
Current dirname: /usr/local/share/locale


MPlayer CVS-030101-14:46-3.2 (C) 2000-2002 Arpad Gereoffy (see DOCS)

CPU: Advanced Micro Devices Duron SF Spitfire (Family: 6, Stepping: 0)
Detected cache-line size is 64 bytes
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 0 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx

Reading config file /usr/local/etc/mplayer/mplayer.conf: No such file or directory
Reading config file /home/filon/.mplayer/config
Reading /home/filon/.mplayer/codecs.conf: can't open '/home/filon/.mplayer/codecs.conf': No such file or directory
Reading /usr/local/etc/mplayer/codecs.conf: 49 audio & 130 video codecs
/home/filon/.mplayer/subfont.ttf doesn't look like a font description, ignoring
Cannot load font: /home/filon/.mplayer/subfont.ttf
Using Linux hardware RTC timing (1024Hz).
Input config file /home/filon/.mplayer/input.conf parsed : 52 binds
Can't open menu config file: /home/filon/.mplayer/menu.conf
Menu inited: /usr/local/etc/mplayer/menu.conf

Playing /home/filon/movies/Megaus.mpg
MPEG-PS file format detected.
VIDEO:  MPEG1  352x288  (aspect 8)  25.00 fps  1687.5 kbps (210.9 kbyte/s)
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
MP3lib: init layer2&3 finished, tables done
AUDIO: 48000 Hz, 2 ch, 16 bit (0x10), ratio: 16000->192000 (128.0 kbit)
Selected audio codec: [mp3] afm:mp3lib (mp3lib MPEG layer-2, layer-3)
==========================================================================
==========================================================================
Forced video codec: foobar
*** Try to upgrade /home/filon/.mplayer/codecs.conf from etc/codecs.conf
*** If it still does not work, read DOCS/codecs.html!
Cannot find codec matching selected -vo and video format 0x10000001!
==========================================================================
alsa-init: testing and bugreports are welcome.
alsa-init: requested format: 48000 Hz, 2 channels, Signed 16-bit (Little-Endian)
alsa-init: 1 soundcard found, using: hw:0,0
alsa9: 48000 Hz/2 channels/4 bpf/65536 bytes buffer/Signed 16 bit Little Endian
AO: [alsa9] 48000Hz 2ch Signed 16-bit (Little-Endian)
Building audio filter chain for 48000Hz/2ch/16bit -> 48000Hz/2ch/16bit...
Video: No video!!!
Start playing...

[here I do the seek]

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 8192 (LWP 8379)]
0x0816a2a8 in demux_seek_mpg (demuxer=0x849b1e8, rel_seek_secs=-nan(0x709b36), flags=0) at demux_mpg.c:365
365             if(!sh_video->i_bps) // unspecified or VBR
(gdb) print sh_video
$1 = (struct {...} *) 0x0

So we have a segfault.

I know, that user will not probably do such thing, but an application
shouldn't segafult even when user is doing something stupid :-)

-- 
Filip Kalinski <filon at pld.org.pl>