[FFmpeg-trac] #7605(undetermined:new): Native opus decoder does not remove padding at start

FFmpeg trac at avcodec.org
Mon Dec 10 14:49:31 EET 2018

#7605: Native opus decoder does not remove padding at start
             Reporter:  jchennales   |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
 Summary of the bug:

 The native opus decoder does not remove padding at start of file

 How to reproduce:

 Using a 10s mono 44k sine wave wav file split in two. The files are
 encoded as opus and then decoded back to wav. When using the native
 (default) decoder the second file has a clear silence at the beginning
 which results in an audible glitch if played right after the first file.
 When forcing libopus as the decoded this does not happen and the files
 join perfectly (albeit some understandable encoding artifacts at the split


 ffmpeg -i sine01.wav -vn -c:a libopus -b:a 64k -vbr on -compression_level
 10 sine01.opus.ogg
 ffmpeg -i sine02.wav -vn -c:a libopus -b:a 64k -vbr on -compression_level
 10 sine02.opus.ogg

 ffmpeg -i sine01.opus.ogg sine01.deopus.wav
 ffmpeg -i sine02.opus.ogg sine02.deopus.wav

 ffmpeg -c:a libopus -i sine01.opus.ogg sine01.deopus_libopus.wav
 ffmpeg -c:a libopus -i sine02.opus.ogg sine02.deopus_libopus.wav

 ffmpeg version 4.1 Copyright (c) 2000-2018 the FFmpeg developers
   built with gcc 8.2.1 (GCC) 20181017
   configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
 fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-
 libbluray --enable-libfreetype --enable-libmp3lame --enable-libopencore-
 amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libopus
 --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora
 --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp
 --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg
 --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-
 libvorbis --enable-libvo-amrwbenc --enable-libmysofa --enable-libspeex
 --enable-libxvid --enable-libaom --enable-libmfx --enable-amf --enable-
 ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec
 --enable-dxva2 --enable-avisynth
   libavutil      56. 22.100 / 56. 22.100
   libavcodec     58. 35.100 / 58. 35.100
   libavformat    58. 20.100 / 58. 20.100
   libavdevice    58.  5.100 / 58.  5.100
   libavfilter     7. 40.101 /  7. 40.101
   libswscale      5.  3.100 /  5.  3.100
   libswresample   3.  3.100 /  3.  3.100
   libpostproc    55.  3.100 / 55.  3.100

Ticket URL: <https://trac.ffmpeg.org/ticket/7605>
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