when decoding wmv file, logging thousands of "0 errors are concealed" messages

[Andrew Ryan]

I get errors like this when trying to decode a WMV file. I don't have copyright for the file so I can't post it to you. The file does decode, although the resulting video has a ton of artifacts.

It seems odd that we're getting messages like "concealing 0 DC, 0 AC, 0 MV errors". This implies we're concealing 0 errors, huh? I put in a patch to suppress this message but it was suggested this is a real problem which should be fixed (​http://ffmpeg.org/pipermail/ffmpeg-devel/2012-January/118576.html)

Here's sample log messages from the command:
/data/users/andrewr/ffmpeg-git-orig/ffmpeg -i /home/andrewr/tmp/concealing0errors.wmv -map 0:1 -pix_fmt yuv420p -r 29.970 -s 400x224 -an -f yuv4mpegpipe - > /dev/null

[vc1 @ 0x137c810] Interlaced frames/fields support is incomplete
[vc1 @ 0x137c810] concealing 0 DC, 0 AC, 0 MV errors
    Last message repeated 17 times
frame=   17 fps=  0 q=0.0 size=    2231kB time=00:00:00.56 bitrate=32226.1kbits/concealing 0 DC, 0 AC, 0 MV errors
[vc1 @ 0x137c810] concealing 0 DC, 0 AC, 0 MV errors
    Last message repeated 15 times
frame=   34 fps= 32 q=0.0 size=    4463kB time=00:00:01.13 bitrate=32225.6kbits/concealing 0 DC, 0 AC, 0 MV errors
[vc1 @ 0x137c810] concealing 0 DC, 0 AC, 0 MV errors
    Last message repeated 15 times
frame=   51 fps= 32 q=0.0 size=    6694kB time=00:00:01.70 bitrate=32225.5kbits/

Output from
ffmpeg -v 9 -loglevel 99 -i /home/andrewr/tmp/concealing0errors.wmv

ffmpeg version N-36427-g46145e8, Copyright (c) 2000-2012 the FFmpeg developers
  built on Jan  4 2012 20:49:17 with gcc 4.1.2 20071124 (Red Hat 4.1.2-42)
  configuration: --disable-sse --disable-ssse3 --cc=/usr/bin/gcc --cxx=/usr/bin/g++
  libavutil      51. 34.100 / 51. 34.100
  libavcodec     53. 50.100 / 53. 50.100
  libavformat    53. 29.100 / 53. 29.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 57.101 /  2. 57.101
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  5.100 /  0.  5.100
[asf @ 0x1375720] Format asf probed with size=2048 and score=100
[asf @ 0x1375720] gpos mismatch our pos=24, end=26
[asf @ 0x1375720] gpos mismatch our pos=24, end=3850
[asf @ 0x1375720] gpos mismatch our pos=24, end=34
[asf @ 0x1375720] gpos mismatch our pos=24, end=38
[asf @ 0x1375720] gpos mismatch our pos=24, end=278
[asf @ 0x1375720] gpos mismatch our pos=24, end=38
[wmav2 @ 0x137bc90] err{or,}_recognition separate: 1; 1
[wmav2 @ 0x137bc90] err{or,}_recognition combined: 1; 10001
[wmav2 @ 0x137bc90] Unsupported bit depth: 0
[vc1 @ 0x137c810] err{or,}_recognition separate: 1; 1
[vc1 @ 0x137c810] err{or,}_recognition combined: 1; 10001
[vc1 @ 0x137c810] Header: DBFE3BF2
[vc1 @ 0x137c810] Advanced Profile level 3:
frmrtq_postproc=7, bitrtq_postproc=31
LoopFilter=0, ChromaFormat=1, Pulldown=1, Interlace: 1
TFCTRflag=0, FINTERPflag=0
[vc1 @ 0x137c810] Entry point: 1044EFC8
[vc1 @ 0x137c810] Entry point info:
BrokenLink=0, ClosedEntry=0, PanscanFlag=0
RefDist=1, Postproc=0, FastUVMC=0, ExtMV=0
DQuant=0, VSTransform=1, Overlap=0, Qmode=0
[asf @ 0x1375720] parser not found for codec wmav2, packets or times may be invalid.
[asf @ 0x1375720] max_analyze_duration 5000000 reached at 5100000
rfps: 29.916667 0.008713
rfps: 29.916667 0.016016
rfps: 30.000000 0.002815
rfps: 59.916667 0.001949
rfps: 29.970030 0.000075
rfps: 59.940060 0.000300
Input #0, asf, from '/home/andrewr/tmp/concealing0errors.wmv':
  Metadata:
    title           : Sněhulák a Marika
    copyright       : © 
    WMFSDKVersion   : 12.0.7601.17514
    WMFSDKNeeded    : 0.0.0.0000
    IsVBR           : 0
  Duration: 00:04:58.23, start: 0.000000, bitrate: 3577 kb/s
    Stream #0:0(eng), 32, 1/1000: Audio: wmav2 (a[1][0][0] / 0x0161), 48000 Hz, 2 channels, s16, 192 kb/s
    Stream #0:1(eng), 182, 1/1000: Video: vc1 (Advanced) (WVC1 / 0x31435657), yuv420p, 1920x1080, 1/1000, 5000 kb/s, 29.97 tbr, 1k tbn, 1k tbc
At least one output file must be specified

[Carl Eugen Hoyos]

Invalid due to missing complete, uncut console output and a duplicate of ticket #275.

Samples are welcome!