ffplay - 4xm codec playback regression

[ami_stuff]

4xm video codec playback regression with ffplay
(gfx bugs)

most likely another libavfilter-caused regression

​http://samples.multimedia.cx/game-formats/4xm/aitd-26.4xm

C:\>ffmpeg -i C:\aitd-26.4xm
FFmpeg version git-N-29181-ga304071, Copyright (c) 2000-2011 the FFmpeg develope
rs
  built on Apr 18 2011 21:24:03 with gcc 4.5.2
  configuration: --enable-gpl --enable-version3 --enable-runtime-cpudetect --ena
ble-memalign-hack --enable-avisynth --enable-bzlib --enable-frei0r --enable-libo
pencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --
enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enabl
e-libx264 --enable-libxavs --enable-libxvid --enable-zlib --cross-prefix=i686-w6
4-mingw32- --target-os=mingw32 --arch=x86_32 --extra-cflags=-I/home/kyle/softwar
e/ffmpeg/external-libraries/win32/include --extra-ldflags=-L/home/kyle/software/
ffmpeg/external-libraries/win32/lib --pkg-config=pkg-config
  libavutil    50. 40. 1 / 50. 40. 1
  libavcodec   52.120. 0 / 52.120. 0
  libavformat  52.108. 0 / 52.108. 0
  libavdevice  52.  4. 0 / 52.  4. 0
  libavfilter   1. 79. 0 /  1. 79. 0
  libswscale    0. 13. 0 /  0. 13. 0
[4xm @ 01CEC000] Estimating duration from bitrate, this may be inaccurate
Input #0, 4xm, from 'C:\aitd-26.4xm':
  Duration: 00:00:08.20, start: 0.000000, bitrate: 1410 kb/s
    Stream #0.0: Video: 4xm, rgb565le, 640x320, 30 tbr, 30 tbn, 30 tbc
    Stream #0.1: Audio: adpcm_4xm, 44100 Hz, 2 channels, s16, 1411 kb/s
At least one output file must be specified

[Carl Eugen Hoyos]

Fixed by Stefano in 10aa5a6c429827b8f2cd5a04680a8d24d5ad8b53.