Crash reading yop

[Carl Eugen Hoyos]

(gdb) r -vcodec yop -i blox.avi
Starting program: ffmpeg_g -vcodec yop -i blox.avi
[Thread debugging using libthread_db enabled]
[New Thread 0xb79116c0 (LWP 20591)]
ffmpeg version N-41080-g394b692 Copyright (c) 2000-2012 the FFmpeg developers
  built on May 28 2012 14:04:27 with gcc 4.3.2
  configuration: --cc=/usr/local/gcc-4.3.2/bin/gcc --enable-gpl --enable-libopenjpeg --enable-libvorbis --enable-libspeex --enable-libmp3lame --enable-libtheora --extra-ldflags=-lm --enable-libvpx --enable-libxavs
  libavutil      51. 55.100 / 51. 55.100
  libavcodec     54. 23.100 / 54. 23.100
  libavformat    54.  6.101 / 54.  6.101
  libavdevice    54.  0.100 / 54.  0.100
  libavfilter     2. 77.100 /  2. 77.100
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb79116c0 (LWP 20591)]
0x086ba8f7 in yop_decode_init (avctx=0x901e700) at libavcodec/yop.c:95
95          s->num_pal_colors = avctx->extradata[0];
(gdb) bt
#0  0x086ba8f7 in yop_decode_init (avctx=0x901e700) at libavcodec/yop.c:95
#1  0x08590345 in avcodec_open2 (avctx=0x901e700, codec=Cannot access memory at address 0x4
)
    at libavcodec/utils.c:925
#2  0x0819e8ac in avformat_find_stream_info (ic=0x9018440, options=0x90183c0)
    at libavformat/utils.c:2485
#3  0x0805682b in opt_input_file (o=0xbfbf1228, opt=0xbfbf3280 "i",
    filename=0xbfbf3282 "blox.avi") at ffmpeg.c:4327
#4  0x08062d72 in parse_option (optctx=0xbfbf1228, opt=0xbfbf3280 "i",
    arg=0xbfbf3282 "blox.avi", options=0x88e7540) at cmdutils.c:305
#5  0x08063103 in parse_options (optctx=0xbfbf1228, argc=5, argv=0xbfbf1454,
    options=0x88e7540, parse_arg_function=0x805d420 <opt_output_file>)
    at cmdutils.c:338
#6  0x0805c4f6 in main (argc=5, argv=0xbfbf1454) at ffmpeg.c:5906
(gdb) disass $pc-32 $pc+32
Dump of assembler code from 0x86ba8d7 to 0x86ba917:
0x086ba8d7 <yop_decode_init+90>:        adc    $0x24,%al
0x086ba8d9 <yop_decode_init+92>:        call   0x87f4cb0 <av_image_check_size>
0x086ba8de <yop_decode_init+97>:        test   %eax,%eax
0x086ba8e0 <yop_decode_init+99>:        js     0x86ba8a1 <yop_decode_init+36>
0x086ba8e2 <yop_decode_init+101>:       movl   $0xb,0x90(%ebx)
0x086ba8ec <yop_decode_init+111>:       mov    %esi,(%esp)
0x086ba8ef <yop_decode_init+114>:       call   0x858de80 <avcodec_get_frame_defaults>
0x086ba8f4 <yop_decode_init+119>:       mov    0x64(%ebx),%eax
0x086ba8f7 <yop_decode_init+122>:       movzbl (%eax),%ecx
0x086ba8fa <yop_decode_init+125>:       mov    %ecx,0x16c(%esi)
0x086ba900 <yop_decode_init+131>:       movzbl 0x1(%eax),%edx
0x086ba904 <yop_decode_init+135>:       mov    %edx,0x170(%esi)
0x086ba90a <yop_decode_init+141>:       movzbl 0x2(%eax),%edx
0x086ba90e <yop_decode_init+145>:       mov    %ecx,%eax
0x086ba910 <yop_decode_init+147>:       add    0x170(%esi),%eax
0x086ba916 <yop_decode_init+153>:       cmp    $0x100,%eax
End of assembler dump.
(gdb) info register
eax            0x0      0
ecx            0x0      0
edx            0x901f100        151122176
ebx            0x901e700        151119616
esp            0xbfbf0c90       0xbfbf0c90
ebp            0x90183c0        0x90183c0
esi            0x901f100        151122176
edi            0x8a81880        145234048
eip            0x86ba8f7        0x86ba8f7 <yop_decode_init+122>
eflags         0x10246  [ PF ZF IF RF ]
cs             0x73     115
ss             0x7b     123
ds             0x7b     123
es             0x7b     123
fs             0x0      0
gs             0x33     51