Recherche avancée

Sur d’autres sites (4366)

• avfilter/af_headphone : Simplify parsing channel mapping string

  27 août 2020, par Andreas Rheinhardt

  avfilter/af_headphone : Simplify parsing channel mapping string
  When parsing the channel mapping string (a string containing '|'
  
  delimited tokens each of which is supposed to contain a channel name
  
  like "FR"), the old code would at each step read up to seven uppercase
  
  characters from the input string and give this to
  
  av_get_channel_layout() to parse. The returned layout is then checked
  
  for being a layout with a single channel set by computing its logarithm.
  Besides being overtly complicated this also has the drawback of relying
  
  on the assumption that every channel name consists of at most seven
  
  uppercase letters only ; but said assumption is wrong : The abbreviation
  
  of the second low frequency channel is LFE2. Furthermore it treats
  
  garbage like "FRfoo" as valid channel.
  This commit changes this by using av_get_channel_layout() directly ;
  
  furthermore, av_get_channel_layout_nb_channels() (which uses popcount)
  
  is used to find out the number of channels instead of the custom code
  
  to calculate the logarithm.
  (As a consequence, certain other formats to specify the channel layouts
  
  are now accepted (like the hex versions of av_get_channel_layout()) ; but
  
  this is actually not bad at all.)
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/af_headphone.c

• avfilter/vf_signature : Avoid cast from function pointer to void*

  25 août 2020, par Andreas Rheinhardt

  avfilter/vf_signature : Avoid cast from function pointer to void*
  The signature filter uses qsort, but its compare function doesn't have
  
  the signature required of such a function ; therefore it casts the
  
  function pointer to void. Yet this is wrong :
  
  C90 only guarantees that one can convert a pointer to any incomplete
  
  type or object type to void* and back with the result comparing equal
  
  to the original which makes pointers to void generic pointers to
  
  incomplete or object type. Yet C90 lacks a generic function pointer
  
  type.
  
  C99 additionally guarantees that a pointer to a function of one type may
  
  be converted to a pointer to a function of another type with the result
  
  and the original comparing equal when converting back.
  
  This makes any function pointer type a generic function pointer type.
  
  Yet even this does not make pointers to void generic function pointers.
  Both GCC and Clang emit warnings for this when in pedantic mode.
  This commit fixes this by modifying the compare function to comply with
  
  the expected signature.
  Reviewed-by : Paul B Mahol <onemda@gmail.com>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/vf_signature.c

• ffmpeg Change audio aac in video to mp3 not working

  17 août 2020, par Geo

  I have a mp4 video, as following, there is aac audio inside, now I need to change it to mp3 by using the command :

  


  ffmpeg -i newvideo6.mp4 -q:a 0 -map 0:a:0 -acodec mp3 -ar 24000 -map v -y newvideo6mp3.mp4

  


  or

  


  ffmpeg -i newvideo6.mp4 -q:a 0 -map 0:a:0 -acodec libmp3lame -ar 24000 -map v -y newvideo6mp3.mp4

  


  or using -q:a 1, all the way to 9, but the resulting video newvideo6mp3.mp4 has no sound, but if I change to :

  


  ffmpeg -i newvideo6.mp4 -q:a 0 -map 0:a:0 -acodec aac -ar 24000 -map v -y newvideo6mp3.mp4

  


  it works, so any clue ?

  


  Thanks

  


  This original video plays sound :
ffmpeg -i newvideo6.mp4
ffmpeg version git-2018-12-17-d54276f Copyright (c) 2000-2018 the FFmpeg developers

  


  built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)

  


  configuration : —prefix=/usr/local —enable-gpl —enable-nonfree —enable-libass —enable-libfdk-aac —enable-libfreetype —enable-libmp3lame —enable-libopus —enable-libtheora —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxvid —enable-libx265

  


  libavutil 56. 24.101 / 56. 24.101

  


  libavcodec 58. 42.102 / 58. 42.102

  


  libavformat 58. 24.101 / 58. 24.101

  


  libavdevice 58. 6.101 / 58. 6.101

  


  libavfilter 7. 46.101 / 7. 46.101

  


  libswscale 5. 4.100 / 5. 4.100

  


  libswresample 3. 4.100 / 3. 4.100

  


  libpostproc 55. 4.100 / 55. 4.100

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'newvideo6.mp4' :

  


  Metadata :

  


  major_brand     : isom
minor_version   : 512
compatible_brands: isomiso2avc1mp41
encoder         : Lavf58.24.101


  


  Duration : 00:00:05.00, start : 0.000000, bitrate : 87 kb/s
Stream #0:0(und) : Video : h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 32 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)

  


  Metadata:
  handler_name    : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 24000 Hz, mono, fltp, 63 kb/s (default)
Metadata:
  handler_name    : SoundHandler


  


  This converted video does not play :

  


  ffmpeg -i newvideo6mp3.mp4

  


  ffmpeg version git-2018-12-17-d54276f Copyright (c) 2000-2018 the FFmpeg developers

  


  built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)

  


  configuration : —prefix=/usr/local —enable-gpl —enable-nonfree —enable-libass —enable-libfdk-aac —enable-libfreetype —enable-libmp3lame —enable-libopus —enable-libtheora —enable-libvorbis —enable-libvpx —enable-libx264 —enable-libxvid —enable-libx265

  


  libavutil 56. 24.101 / 56. 24.101

  


  libavcodec 58. 42.102 / 58. 42.102

  


  libavformat 58. 24.101 / 58. 24.101

  


  libavdevice 58. 6.101 / 58. 6.101

  


  libavfilter 7. 46.101 / 7. 46.101

  


  libswscale 5. 4.100 / 5. 4.100

  


  libswresample 3. 4.100 / 3. 4.100

  


  libpostproc 55. 4.100 / 55. 4.100

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'newvideo6mp3.mp4' :

  


  Metadata :
major_brand : isom
minor_version : 512
compatible_brands : isomiso2avc1mp41
encoder : Lavf58.24.101

  


  Duration : 00:00:05.00, start : 0.000000, bitrate : 89 kb/s
Stream #0:0(und) : Audio : mp3 (mp4a / 0x6134706D), 24000 Hz, mono, fltp, 64 kb/s (default)

  


  Metadata:
  handler_name    : SoundHandler
Stream #0:1(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360, 32 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
Metadata:
  handler_name    : VideoHandler