Crash decoding motionpixels

[Carl Eugen Hoyos]

(gdb) r -vcodec motionpixels -i blox.avi -f null -
Starting program: ffmpeg_g -vcodec motionpixels -i blox.avi -f null -
[Thread debugging using libthread_db enabled]
[New Thread 0xb79566c0 (LWP 20922)]
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
Input #0, avi, from 'blox.avi':
  Duration: 00:00:12.64, start: 0.000000, bitrate: 788 kb/s
    Stream #0:0: Video: motionpixels (BLOX / 0x584F4C42), rgb555le, 320x240, 23.97 tbr, 23.97 tbn, 23.97 tbc
[buffer @ 0x901ff40] w:320 h:240 pixfmt:rgb555le tb:100/2397 sar:0/1 sws_param:flags=2
[buffersink @ 0x9010160] No opaque field provided
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf54.6.101
    Stream #0:0: Video: rawvideo (RGB[15] / 0xF424752), rgb555le, 320x240, q=2-31, 200 kb/s, 90k tbn, 23.97 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (motionpixels -> rawvideo)
Press [q] to stop, [?] for help

Program received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0xb79566c0 (LWP 20922)]
0x08464ab9 in mp_decode_frame (avctx=0x901e6e0, data=0x90105c0,
    data_size=0xbfd16bd4, avpkt=0xbfd16810) at libavcodec/motionpixels.c:268
268         for (i = !(avctx->extradata[1] & 2); i < 2; ++i) {
(gdb) bt
#0  0x08464ab9 in mp_decode_frame (avctx=0x901e6e0, data=0x90105c0,
    data_size=0xbfd16bd4, avpkt=0xbfd16810) at libavcodec/motionpixels.c:268
#1  0x0858e1a5 in avcodec_decode_video2 (avctx=0x901e6e0, picture=0x90105c0,
    got_picture_ptr=0xbfd16ab4, avpkt=0xb7c26140) at libavcodec/utils.c:1464
#2  0x08058a3e in output_packet (ist=0x901ef40, pkt=0xbfd17f4c)
    at ffmpeg.c:2645
#3  0x0805b410 in transcode () at ffmpeg.c:3662
#4  0x0805c556 in main (argc=Cannot access memory at address 0x0
) at ffmpeg.c:5926
(gdb) disass $pc-32 $pc+32
Dump of assembler code from 0x8464a99 to 0x8464ad9:
0x08464a99 <mp_decode_frame+409>:       add    %al,(%eax)
0x08464a9b <mp_decode_frame+411>:       movl   $0x0,0x4(%esp)
0x08464aa3 <mp_decode_frame+419>:       mov    %eax,0x8(%esp)
0x08464aa7 <mp_decode_frame+423>:       mov    %edx,(%esp)
0x08464aaa <mp_decode_frame+426>:       call   0x804c4c4 <memset@plt>
0x08464aaf <mp_decode_frame+431>:       mov    0xc0(%esp),%esi
0x08464ab6 <mp_decode_frame+438>:       mov    0x64(%esi),%eax
0x08464ab9 <mp_decode_frame+441>:       movzbl 0x1(%eax),%edi
0x08464abd <mp_decode_frame+445>:       shr    %edi
0x08464abf <mp_decode_frame+447>:       xor    $0x1,%edi
0x08464ac2 <mp_decode_frame+450>:       and    $0x1,%edi
0x08464ac5 <mp_decode_frame+453>:       lea    0x0(%esi),%esi
0x08464ac8 <mp_decode_frame+456>:       mov    0xa0(%esp),%eax
0x08464acf <mp_decode_frame+463>:       mov    0x98(%esp),%ebx
0x08464ad6 <mp_decode_frame+470>:       mov    0xa8(%esp),%ebp
End of assembler dump.
(gdb) info register
eax            0x0      0
ecx            0x0      0
edx            0x0      0
ebx            0x90109c0        151062976
esp            0xbfd16710       0xbfd16710
ebp            0xbfd16810       0xbfd16810
esi            0x901e6e0        151119584
edi            0xffffffff       -1
eip            0x8464ab9        0x8464ab9 <mp_decode_frame+441>
eflags         0x10246  [ PF ZF IF RF ]
cs             0x73     115
ss             0x7b     123
ds             0x7b     123
es             0x7b     123
fs             0x0      0
gs             0x33     51