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• vulkan : add support for encode and decode queues and refactor queue code

  7 novembre 2021, par Lynne

  vulkan : add support for encode and decode queues and refactor queue code
  This simplifies and makes queue family picking simpler and more robust.
  
  The requirements on the device context are relaxed. They made no sense
  
  in the first place.
  The video encode/decode extension is still in beta, at least on paper,
  
  but I really doubt they'd change needing a separate queue family.
  

  • [DH] libavfilter/vf_avgblur_vulkan.c
  • [DH] libavfilter/vf_chromaber_vulkan.c
  • [DH] libavfilter/vf_overlay_vulkan.c
  • [DH] libavfilter/vf_scale_vulkan.c
  • [DH] libavfilter/vulkan.h
  • [DH] libavutil/hwcontext_vulkan.c
  • [DH] libavutil/hwcontext_vulkan.h

• How to put H264 encoded data, inside a container like .mp4 using libAV libraries (ffmpeg) ?

  27 mai 2022, par Vivekanand V

  I have been playing around with the libAV* family of libraries, that comes along with FFMPEG and I am learning how to implement things like encoding, decoding, muxing etc.

  


  I came across this code : https://libav.org/documentation/doxygen/master/encode_video_8c-example.html , that encodes, YUV frames, to a file, using an encoder. In my implementation, I will change the encoder to H264 using avcodec_find_encoder(AV_CODEC_ID_H264) But I do not know, how to put this encoded data, into a proper container (.mp4) using libav libraries, so that the output file, can be played by any media player like VLC, QuickTime, etc...

  


  Can anyone please help me on that ? Every help will be greatly appreciated !

  


• ffmpeg for archival and convertibility

  27 juillet 2021, par Satya

  I've got a couple hundred gigs of *.dv files. I'd like to convert them to H.264 or something else or even leave them alone. The purpose is archival, with an eye to maximum convertibility especially to DVD. The content is family videos.

  


  Would this be fine ?

  


  ffmpeg -i input.dv \
    -c:v libx264 -preset slower \
    -crf 17 \
    -pix_fmt yuv420p \
    output.mp4


  


  I went with the slower preset because encoding time isn't an issue and I'd like a smaller file size. crf 17 is for least-lossy while being widely playable. I read somewhere that yuv420p is needed for some Quicktime players.

  


  Should I throw in -c:a aac for AAC audio ? The audio is voice only, no need for music-hall quality.

  


  I looked at https://trac.ffmpeg.org/wiki/Encode/H.264 for previous research and that's where I got those settings, but it is silent on the audio settings.

  


  Edited : My priorities, in order of importance, are :

  


  

  1. Compatibility

  


  2. Losslessness (doesn't have to be 100% lossless, hence crf of 17 and not 0)

  


  3. File size

  


  


  Most of the input files say this :

  


  [lavf] stream 0: video (dvvideo), -vid 0
[lavf] stream 1: audio (pcm_s16le), -aid 0
VIDEO:  [dvsd]  720x480  0bpp  29.970 fps  25000.0 kbps (3051.8 kbyte/s)
Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV)
AUDIO: 32000 Hz, 2 ch, s16le, 1024.0 kbit/100.00% (ratio: 128000->128000)
Selected audio codec: [pcm] afm: pcm (Uncompressed PCM)


  


  Output from ffmpeg :

  


  Stream #0:1: Audio: pcm_s16le, 32000 Hz, stereo, s16, 1024 kb/s