[MPlayer-users] mplayer/SDL seg fault in switch from fullscreen mode

Nilmoni Deb ndeb at ece.cmu.edu
Thu Oct 3 17:28:02 CEST 2002


Using current cvs (mplayer, ffmpeg) and SDL of Sept. 16. 
Configured mplayer with SDL support.
Running mplayer on a duron CPU (mplayer auto-configured for athlon
optimizations).

When playing a MPEG1 video with these options:

	mplayer -v -fs -vo sdl -framedrop movie.mpg

I press 'f' to switch between fullscreen (fs) and non-fullscreen
(no_fs) modes. After one cycle (fs->no_fs->fs), mplayer crashes when
going from fs to no_fs mode. The bug is 100% reproducible.

Last part of GDB backtrace output is as follows:

*** [vo] Allocating mp_image_t, 352x240x12bpp YUV planar, 126720 bytes
*** [vo] Allocating mp_image_t, 352x240x12bpp YUV planar, 126720 bytes%
*** [vo] Allocating mp_image_t, 352x240x12bpp YUV planar, 126720 bytes%
A:   5.3 V:   5.3 A-V:  0.007 ct:  0.043  136/136   6% 72%  1.3% 21 0 0%
Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 1024 (LWP 15314)]
0x40072d2b in copy_row () from /opt/sdl//lib/libSDL-1.2.so.0
(gdb) bt
#0  0x40072d2b in copy_row () from /opt/sdl//lib/libSDL-1.2.so.0
#1  0x4004155a in SDL_SoftStretch (src=0x840e0d0, srcrect=0xbfffe508, 
    dst=0x840ca30, dstrect=0x840ca50) at SDL_stretch.c:264
#2  0x40045683 in SDL_DisplayYUV_SW (_this=0x8408920, overlay=0x83cfd60, 
    dstrect=0x840ca50) at SDL_yuv_sw.c:1288
#3  0x40044657 in SDL_DisplayYUVOverlay (overlay=0x83cfd60,
dstrect=0x840ca50)
    at SDL_yuv.c:82


I checked the contents of the file SDL_stretch.c and got these lines:

    263 #ifdef __GNUC__
    264                         __asm__ __volatile__ ("
    265                                 call _copy_row
    266                         "
    267                         : "=&D" (u1), "=&S" (u2)
    268                         : "0" (dstp), "1" (srcp)
    269                         : "memory" );
    270 #else

Its clear that the seg fault is at the assembly instruction copy_row
so this may be an SDL bug. But I reported it anyway in case this is an
mplayer bug. Just for info, I am using a video card which has _no_
xvideo support:

X-Video Extension version 2.2
screen #0
 no adaptors present

This means no YUV overlay support. Could that be a cause ?

thanks
- Nil




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