on2avc (0x0500): add support for stereo mode

[ami_stuff]

looks like this codec can support stereo as well

​https://samples.mplayerhq.hu/V-codecs/VP7/troy-700.vp7

​https://samples.mplayerhq.hu/V-codecs/VP7/potter-500.vp7

C:\>ffmpeg -i C:\troy-700.vp7
ffmpeg version N-79546-g13406b6 Copyright (c) 2000-2016 the FFmpeg developers
  built 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      55. 22.100 / 55. 22.100
  libavcodec     57. 35.100 / 57. 35.100
  libavformat    57. 34.102 / 57. 34.102
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 44.100 /  6. 44.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
[on2avc @ 0x2c3e700] 0x500 version should be mono
[avi @ 0x2894020] Failed to open codec in av_find_stream_info
[on2avc @ 0x2c3e700] 0x500 version should be mono
Input #0, avi, from 'C:\troy-700.vp7':
  Duration: 00:01:21.46, start: 0.000000, bitrate: 809 kb/s
    Stream #0:0: Video: vp7 (VP70 / 0x30375056), yuv420p, 624x352, 696 kb/s, 23.
98 fps, 23.98 tbr, 23.98 tbn
    Stream #0:1: Audio: avc ([0][5][0][0] / 0x0500), 44100 Hz, stereo, fltp, 96
kb/s
At least one output file must be specified

also with this sample:

​https://www.datafilehost.com/d/7a9af464

I get:

C:\>ffmpeg -i 0x0500_mono_taking-300.vp7 -f null -
ffmpeg version N-79546-g13406b6 Copyright (c) 2000-2016 the FFmpeg developers
  built 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      55. 22.100 / 55. 22.100
  libavcodec     57. 35.100 / 57. 35.100
  libavformat    57. 34.102 / 57. 34.102
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 44.100 /  6. 44.100
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  0.101 /  2.  0.101
  libpostproc    54.  0.100 / 54.  0.100
Input #0, avi, from '0x0500_mono_taking-300.vp7':
  Duration: 00:02:30.66, start: 0.000000, bitrate: 352 kb/s
    Stream #0:0: Video: vp7 (VP70 / 0x30375056), yuv420p, 480x256, 293 kb/s, 23.
98 fps, 23.98 tbr, 23.98 tbn
    Stream #0:1: Audio: avc ([0][5][0][0] / 0x0500), 32000 Hz, mono, fltp, 48 kb
/s
[null @ 0x2c38600] Using AVStream.codec to pass codec parameters to muxers is de
precated, use AVStream.codecpar instead.
    Last message repeated 1 times
Output #0, null, to 'pipe:':
  Metadata:
    encoder         : Lavf57.34.102
    Stream #0:0: Video: wrapped_avframe, yuv420p, 480x256, q=2-31, 200 kb/s, 23.
98 fps, 23.98 tbn
    Metadata:
      encoder         : Lavc57.35.100 wrapped_avframe
    Stream #0:1: Audio: pcm_s16le, 32000 Hz, mono, s16, 512 kb/s
    Metadata:
      encoder         : Lavc57.35.100 pcm_s16le
Stream mapping:
  Stream #0:0 -> #0:0 (vp7 (native) -> wrapped_avframe (native))
  Stream #0:1 -> #0:1 (avc (on2avc) -> pcm_s16le (native))
Press [q] to stop, [?] for help
frame=  208 fps=0.0 q=-0.0 size=N/A time=00:00:08.67 bitrate=N/A speed=17.4x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame=  478 fps=0.0 q=-0.0 size=N/A time=00:00:19.93 bitrate=N/A speed=19.9x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame=  741 fps=494 q=-0.0 size=N/A time=00:00:30.90 bitrate=N/A speed=20.6x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 1008 fps=504 q=-0.0 size=N/A time=00:00:42.04 bitrate=N/A speed=  21x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 1276 fps=510 q=-0.0 size=N/A time=00:00:53.21 bitrate=N/A speed=21.3x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 1545 fps=515 q=-0.0 size=N/A time=00:01:04.43 bitrate=N/A speed=21.5x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 1814 fps=518 q=-0.0 size=N/A time=00:01:15.66 bitrate=N/A speed=21.6x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 2078 fps=520 q=-0.0 size=N/A time=00:01:26.67 bitrate=N/A speed=21.7x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 2323 fps=516 q=-0.0 size=N/A time=00:01:36.88 bitrate=N/A speed=21.5x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 2579 fps=516 q=-0.0 size=N/A time=00:01:47.56 bitrate=N/A speed=21.5x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 2836 fps=516 q=-0.0 size=N/A time=00:01:58.28 bitrate=N/A speed=21.5x
frame= 3115 fps=519 q=-0.0 size=N/A time=00:02:09.92 bitrate=N/A speed=21.7x
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
[on2avc @ 0x2c4b020] stereo mode window for mono audio
Error while decoding stream #0:1: Invalid data found when processing input
frame= 3393 fps=522 q=-0.0 size=N/A time=00:02:21.52 bitrate=N/A speed=21.8x
frame= 3612 fps=528 q=-0.0 Lsize=N/A time=00:02:30.65 bitrate=N/A speed=  22x

video:1354kB audio:9236kB subtitle:0kB other streams:0kB global headers:0kB muxi
ng overhead: unknown

[Elon Musk]

Fixed in 187c4273351f517a343c00ac470e1952edbd2e9b.
Have same issues as 0x501 for stereo files.