wvc1: artefacts with interlaced bottom field first

[ami_stuff]

see also ticket #2531 (top field first)

C:\>ffmpeg -i interlaced_bottom.wmv -an -vcodec msmpeg4v2 out.avi
ffmpeg version N-59133-gffbcb1c Copyright (c) 2000-2013 the FFmpeg developers
  built on Dec 16 2013 02:29:41 with gcc 4.5.0 (GCC) 20100414 (Fedora MinGW 4.5.
0-1.fc14)
  configuration: --prefix=/var/www/users/research/ffmpeg/snapshots/build --arch=
x86 --target-os=mingw32 --cross-prefix=i686-pc-mingw32- --cc='ccache i686-pc-min
gw32-gcc' --enable-pthreads --enable-memalign-hack --enable-runtime-cpudetect --
enable-cross-compile --enable-static --disable-shared --extra-libs='-lws2_32 -lw
inmm -lpthread' --extra-cflags='--static -I/var/www/users/research/ffmpeg/snapsh
ots/build/include' --extra-ldflags='-static -L/var/www/users/research/ffmpeg/sna
pshots/build/lib' --enable-bzlib --enable-zlib --enable-gpl --enable-version3 --
enable-nonfree --enable-libx264 --enable-libspeex --enable-libtheora --enable-li
bvorbis --enable-libfaac --enable-libxvid --enable-libopencore-amrnb --enable-li
bopencore-amrwb --enable-libmp3lame --enable-libfreetype --enable-libvpx --disab
le-decoder=libvpx
  libavutil      52. 58.100 / 52. 58.100
  libavcodec     55. 45.101 / 55. 45.101
  libavformat    55. 22.100 / 55. 22.100
  libavdevice    55.  5.102 / 55.  5.102
  libavfilter     3. 92.100 /  3. 92.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Guessed Channel Layout for  Input Stream #0.0 : stereo
Input #0, asf, from 'interlaced_bottom.wmv':
  Metadata:
    WMFSDKVersion   : 11.0.5721.5275
    WMFSDKNeeded    : 0.0.0.0000
    Buffer Average  : 1544
    VBR Peak        : 759440
    IsVBR           : 1
    DeviceConformanceTemplate: AP@L3
  Duration: 00:00:12.67, start: 0.026000, bitrate: 1034 kb/s
    Stream #0:0(pol): Audio: wmav2 (a[1][0][0] / 0x0161), 44100 Hz, stereo, fltp
, 281 kb/s
    Stream #0:1(pol): Video: vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 320x24
0, 915 kb/s, 23.98 tbr, 1k tbn, 1k tbc
Output #0, avi, to 'out.avi':
  Metadata:
    WMFSDKVersion   : 11.0.5721.5275
    WMFSDKNeeded    : 0.0.0.0000
    Buffer Average  : 1544
    VBR Peak        : 759440
    IsVBR           : 1
    DeviceConformanceTemplate: AP@L3
    ISFT            : Lavf55.22.100
    Stream #0:0(pol): Video: msmpeg4v2 (MP42 / 0x3234504D), yuv420p, 320x240, q=
2-31, 200 kb/s, 23.98 tbn, 23.98 tbc
Stream mapping:
  Stream #0:1 -> #0:0 (vc1 -> msmpeg4v2)
Press [q] to stop, [?] for help
[vc1 @ 0x225e480] Referenced frame missing.
[msmpeg4v2 @ 0x222c380] warning, clipping 1 dct coefficients to -127..127
    Last message repeated 1 times
frame=  303 fps=0.0 q=4.6 Lsize=     410kB time=00:00:12.63 bitrate= 265.8kbits/
s
video:397kB audio:0kB subtitle:0 global headers:0kB muxing overhead 3.222951%

[Carl Eugen Hoyos]

The issue has improved but there is still a noticeable green artefact visible.

[Michael Niedermayer]

Fixed in b51cc701bc4ac34959944f30ca8a7e01e1338d43