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• mpegaudiodecheader : check the header in avpriv_mpegaudio_decode_header

  9 octobre 2015, par Anton Khirnov

  mpegaudiodecheader : check the header in avpriv_mpegaudio_decode_header
  Almost all the places from which this function is called already check
  
  the header manually and in the two that don’t (the mp3 muxer) the check
  
  should not cause any problems.
  

  • [DBH] libavcodec/libmp3lame.c
  • [DBH] libavcodec/mpegaudiodec_template.c
  • [DBH] libavcodec/mpegaudiodecheader.c
  • [DBH] libavformat/mp3dec.c
  • [DBH] libavformat/mp3enc.c

• dxva : preparations for new hwaccel API

  6 juin 2017, par wm4

  dxva : preparations for new hwaccel API
  The actual hwaccel code will need to access an internal context instead
  
  of avctx->hwaccel_context, so add a new DXVA_CONTEXT() macro, that will
  
  dispatch between the "old" external and the new internal context.
  Also, the new API requires a new D3D11 pixfmt, so all places which check
  
  for the pixfmt need to be adjusted. Introduce a ff_dxva2_is_d3d11()
  
  function, which does the check.
  Signed-off-by : Diego Biurrun <diego@biurrun.de>
  

  • [DBH] libavcodec/dxva2.c
  • [DBH] libavcodec/dxva2_h264.c
  • [DBH] libavcodec/dxva2_hevc.c
  • [DBH] libavcodec/dxva2_internal.h
  • [DBH] libavcodec/dxva2_mpeg2.c
  • [DBH] libavcodec/dxva2_vc1.c

• FFmpeg concat demuxer and handling encrypted chunks

  23 janvier 2020, par cellardoor_ncx

  I’m trying to process a remote m3u8 playlist containing (a possibly encrypted) HLS stream. The output I’m looking for is a mp4 container with MPEG-4 inside.

  The playlist is a result of an ended live stream and may contain EXT-X-DISCONTINUITY tags. As I understand, there’s no "built-in" way to process it and indeed, there are plenty of warnings like "Non-monotonous DTS in output stream" and the resulting file always has some playback issues.

  There are a couple of options to "glue" it. On an unencrypted stream, I found concat demuxer to produce the result with the least playback problems. The command is :

  LIST=chunks.list; ffmpeg -loglevel 'debug' -f concat -safe 0 -protocol_whitelist "file,http,https,tcp,tls,crypto" -i $LIST -c copy -movflags frag_keyframe -y output_concat.mp4

  where chunks.list is something like :

  file 'https://www.example.org/chunk1.ts'
  
  file 'https://www.example.org/chunk2.ts'
  
  file 'https://www.example.org/chunk3.ts'

  Now, I’m trying to use concat demuxer to process encrypted chunks. I’ve tried passing -key and -iv options in different places and changing chunks.list to be like file 'crypto+https...' but it won’t pick up encryption key :

  Opening an input file: chunks.list.
  
  [concat @ 0x7f9fb6800c00] Opening 'chunks.list' for reading
  
  [NULL @ 0x7f9fb6007e00] Opening 'crypto+https://www.example.org/chunk1.ts' for reading
  
  [crypto @ 0x7f9fb5700a00] decryption key not set
  
  [concat @ 0x7f9fb6800c00] Impossible to open 'crypto+https://www.example.org/chunk1.ts'
  
  [AVIOContext @ 0x7f9fb5700780] Statistics: 5094 bytes read, 0 seeks
  
  chunks.list: Invalid argument

  Docs mention encryption options for crypto protocol, so it looks it’s just a matter of passing these in a proper way.

  When, instead of using concat demuxer, I try to process and decrypt only one chunk like :
  ffmpeg -i crypto+https://www.example.org/chunk1.ts -key  -iv  chunk1.ts it works fine. There’s nothing wrong with the key itself, I’m able to decrypt it with other tools (openssl etc).

  Is it possible for concat demuxer to handle decryption ? If so, where should I pass key and iv options ?