mpeg4enc: crash with 1x1 resolution

[ami_stuff]

while experimenting with wmv encoder I have found out that it's possible to crash all mpeg-based encoders (wmv1/2/msmpeg4v2/mpeg1video/mpeg2video etc.) with input which have 1x1 resolution (or 2x1, 1x2 - more I didn't test)

(gdb) r -i 1.avi -vcodec msmpeg4 -f null -
The program being debugged has been started already.
Start it from the beginning? (y or n) y

Starting program: d:\mingw\msys\1.0\ffmpeg-head-23fba3e\ffmpeg_g.exe -i 1.avi -v
codec msmpeg4 -f null -
[New Thread 3096.0xd3c]
ffmpeg version 0.10.2.git-23fba3e Copyright (c) 2000-2012 the FFmpeg developers
  built on May  5 2012 19:57:06 with gcc 4.6.1
  configuration: --disable-ffprobe --enable-gpl
  libavutil      51. 49.100 / 51. 49.100
  libavcodec     54. 19.100 / 54. 19.100
  libavformat    54.  4.100 / 54.  4.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 72.104 /  2. 72.104
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0. 11.100 /  0. 11.100
  libpostproc    52.  0.100 / 52.  0.100
Input #0, avi, from '1.avi':
  Duration: 00:00:00.10, start: 0.000000, bitrate: 663 kb/s
    Stream #0:0: Video: cinepak (cvid / 0x64697663), yuv420p, 1x1, 10 tbr, 10 tb
n, 10 tbc
[buffer @ 03b41fc0] w:1 h:1 pixfmt:yuv420p tb:1/1000000 sar:0/1 sws_param:flags=
2
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf54.4.100
    Stream #0:0: Video: msmpeg4, yuv420p, 1x1, q=2-31, 200 kb/s, 90k tbn, 10 tbc

Stream mapping:
  Stream #0:0 -> #0:0 (cinepak -> msmpeg4)
Press [q] to stop, [?] for help

Program received signal SIGILL, Illegal instruction.
0x00a01f00 in ff_emu_edge_core_sse ()
(gdb) bt
#0  0x00a01f00 in ff_emu_edge_core_sse ()
#1  0x03b35ce0 in ?? ()
Backtrace stopped: previous frame inner to this frame (corrupt stack?)