[FFmpeg-trac] #5425(undetermined:new): improve iac decoder

[FFmpeg]

#5425: improve iac decoder
-------------------------------------+-------------------------------------
               Reporter:  ami_stuff  |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:
                Version:             |  undetermined
  unspecified                        |               Keywords:
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 currently ffmpeg's decoder is not as good as the original one

 https://samples.ffmpeg.org/A-codecs/Indeo_audio/hvalen.avi


 for example there are some overflows or something with this file:

 https://samples.ffmpeg.org/A-codecs/Indeo_audio/2heelsidemobe.AVI

 {{{
 C:\>ffmpeg -i C:\2heelsidemobe.AVI out.avi
 ffmpeg version N-78758-g5156578 Copyright (c) 2000-2016 the FFmpeg
 developers
   built with gcc 5.3.0 (GCC)
   configuration: --enable-gpl --enable-version3 --disable-w32threads
 --enable-av
 isynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls
 --enab
 le-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-
 libcaca --
 enable-libdcadec --enable-libfreetype --enable-libgme --enable-libgsm
 --enable-l
 ibilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb
 --enab
 le-libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-
 librtmp --en
 able-libschroedinger --enable-libsoxr --enable-libspeex --enable-libtheora
 --ena
 ble-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-
 libvorbis --
 enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264
 --enable-lib
 x265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma
 --enable-d
 ecklink --enable-zlib
   libavutil      55. 19.100 / 55. 19.100
   libavcodec     57. 27.100 / 57. 27.100
   libavformat    57. 26.100 / 57. 26.100
   libavdevice    57.  0.101 / 57.  0.101
   libavfilter     6. 37.100 /  6. 37.100
   libswscale      4.  0.100 /  4.  0.100
   libswresample   2.  0.101 /  2.  0.101
   libpostproc    54.  0.100 / 54.  0.100
 [avi @ 038de6e0] non-interleaved AVI
 Input #0, avi, from 'C:\2heelsidemobe.AVI':
   Duration: 00:00:02.87, start: 0.000000, bitrate: 1255 kb/s
     Stream #0:0: Video: indeo4 (IV41 / 0x31345649), yuv410p, 240x180, 1099
 kb/s,
  15 fps, 15 tbr, 15 tbn, 15 tbc
     Metadata:
       title           : C:\Galleries\Main Gallery\TMPVIDEO\IVCSATMP.AVI
     Stream #0:1: Audio: iac ([2][4][0][0] / 0x0402), 44100 Hz, stereo,
 fltp, 176
  kb/s
     Metadata:
       title           : C:\Galleries\Main Gallery\TMPVIDEO\IVCSATMP.AVI
 Output #0, avi, to 'out.avi':
   Metadata:
     ISFT            : Lavf57.26.100
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 240x180,
 q=2-31, 200
  kb/s, 15 fps, 15 tbn, 15 tbc
     Metadata:
       title           : C:\Galleries\Main Gallery\TMPVIDEO\IVCSATMP.AVI
       encoder         : Lavc57.27.100 mpeg4
     Side data:
       cpb: bitrate max/min/avg: 0/0/200000 buffer size: 0 vbv_delay: -1
     Stream #0:1: Audio: mp3 (libmp3lame) (U[0][0][0] / 0x0055), 44100 Hz,
 stereo
 , fltp
     Metadata:
       title           : C:\Galleries\Main Gallery\TMPVIDEO\IVCSATMP.AVI
       encoder         : Lavc57.27.100 libmp3lame
 Stream mapping:
   Stream #0:0 -> #0:0 (indeo4 (native) -> mpeg4 (native))
   Stream #0:1 -> #0:1 (iac (native) -> mp3 (libmp3lame))
 Press [q] to stop, [?] for help
 [iac @ 038e06a0] Potential problem on band 26, coefficient 187: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 188: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 189: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 190: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 192: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 193: cw_len=1
 [iac @ 038e06a0] Potential problem on band 26, coefficient 194: cw_len=1
 frame=   41 fps=0.0 q=10.5 Lsize=     187kB time=00:00:02.86 bitrate=
 534.9kbits
 /s speed=10.8x
 video:129kB audio:44kB subtitle:0kB other streams:0kB global headers:0kB
 muxing
 overhead: 7.720324%
 }}}

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5425>
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