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• Special invisible frames in the beginning of the avi-files. How to recognize/handle them correctly ?

  20 avril 2018, par bukkojot

  I wrote simple video editing software, it just splits video by keyframes and nothing more. It works fine, until I found 1 strange file.

  Here exists 1 "invisible frame" with 2 NALs : SPS and PPS. If I remove this single frame, whole other file is unreadable. Other frames marked as keyframes, but not have this SPS and PPS headers.

  

  If you look at a normal file encoded with the same codec, then you see these special headers are included in each keyframe :

  

  Since my program just took and cut the frames from the beginning of the file, then such a file just stopped working ! I try to do the same with ffmpeg :

        ffmpeg -ss 10:00 -i file.avi -c copy -t 10 out.avi

  And also got broken file !

  I checked reference for AVI files and don’t see here any notes about special handling of such invisible frames. What I should read/do to handle such files properly ?

• opus : Add Special Hybrid Folding (per RFC8251)

  2 décembre 2017, par Andrew D'Addesio

  opus : Add Special Hybrid Folding (per RFC8251)
  This decoder-side change, introduced in RFC 8251 (section 9), slightly
  
  improves the decoded quality of 16kbps speech in Hybrid Mode.
  Differences can be seen/heard in testvector05.bit, testvector06.bit,
  
  and testvector12.bit in the RFC 6716/8251 testvectors found here :
  
  https://people.xiph.org/~greg/opus_testvectors/
  Signed-off-by : Andrew D'Addesio <modchipv12@gmail.com>
  

  • [DH] libavcodec/opus_celt.c

• Escape special characters in FFmpeg subtitle filename

  15 janvier 2024, par forthrin

  If your subtitle file name is "Hi, y'all.srt", how do you escape this properly for FFmpeg ? The comma works escaped with backslash, but I can't get the quote to work no matter what tricks I try !

  



  $ ffmpeg -vf subtitles="Hi\, y\\\'all.srt" -t 1 -f null -

ffmpeg version 3.3.3 Copyright (c) 2000-2017 the FFmpeg developers
  built with Apple LLVM version 8.1.0 (clang-802.0.42)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/3.3.3 --enable-shared --enable-pthreads --enable-gpl --enable-version3 --enable-hardcoded-tables --enable-avresample --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-libass --enable-libmp3lame --enable-libx264 --enable-libx265 --enable-libxvid --enable-opencl --enable-videotoolbox --disable-lzma --enable-vda
  libavutil      55. 58.100 / 55. 58.100
  libavcodec     57. 89.100 / 57. 89.100
  libavformat    57. 71.100 / 57. 71.100
  libavdevice    57.  6.100 / 57.  6.100
  libavfilter     6. 82.100 /  6. 82.100
  libavresample   3.  5.  0 /  3.  5.  0
  libswscale      4.  6.100 /  4.  6.100
  libswresample   2.  7.100 /  2.  7.100
  libpostproc    54.  5.100 / 54.  5.100
[Parsed_subtitles_0 @ 0x7fba7af36080] Shaper: FriBidi 0.19.7 (SIMPLE) HarfBuzz-ng 1.4.8 (COMPLEX)
[Parsed_subtitles_0 @ 0x7fba7af36080] Unable to open Hi, yall.srt
[AVFilterGraph @ 0x7fba7ad05d60] Error initializing filter 'subtitles' with args 'Hi, y\all.srt'
Error reinitializing filters!
Failed to inject frame into filter network: No such file or directory
Error while processing the decoded data for stream #0:0
Conversion failed!