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• How to map ffmpeg formats to MIME types and file extensions ?

  17 mai 2017, par odigity

  Anyone know of a reference for mapping ffmpeg format values to MIME types and recommended file extension ? My google attempt failed to turn up anything.

  I did manually put together a small list with guess-work and clues from Wikipedia, IANA, and the Mozilla Developer Network for the subset of formats that I encountered in my video input test collection :

  ffmpeg Format             Extension  MIME Type
  
  ───────────────────────   ─────────  ────────────────────── 
  
  asf                       asf        application/vnd.ms-asf
  
  avi                       avi        video/x-msvideo
  
  flv                       flv        video/x-flv
  
  matroska,webm             webm       video/webm
  
  m4v                       m4v        video/x-m4v
  
  mov,mp4,m4a,3gp,3g2,mj2   mp4        video/mp4
  
  mpeg                      mpeg       video/mpeg
  
  mpegts                    mpeg       video/mpeg
  
  mpegvideo                 mpeg       video/mpeg
  
  ogg                       ogv        video/ogg
  
  matroska                  mkv        video/x-matroska
  
  webm                      webm       video/webm

  No idea if I’ve made the right calls, though.

  (The test files already have file extensions, but I’m operating on the assumption that the extension of a file a user uploads is irrelevant, and that the file should be renamed based on ffprobe and intelligent mapping...)

• ffmpeg - Concat multi mp4 files with audio file not working

  29 mars 2017, par Thanh Dao

  I follow this thread to concat multi mp4 files with audio file.
  But its not success. Have a lots error notifications had been displayed. I dont know how to fix it.
  Below is my command :

  "ffmpeg" -f concat -safe 0 \
  
  -i /path/to/text.txt \
  
  -i /path/to/audio.mp3 -vsync vfr -vf scale="640:640" -pix_fmt yuv420p \
  
  /path/to/output.mp4 2>&1

  The detail contents of text.txt

  file '/path/to/file1.mp4'
  
  file '/path/to/file2.mp4'
  
  file '/path/to/file3.mp4'
  
  file '/path/to/file4.mp4'
  
  file '/path/to/file5.mp4'
  
  file '/path/to/file6.mp4'
  
  file '/path/to/file7.mp4'
  
  file '/path/to/file8.mp4'
  
  file '/path/to/file9.mp4'
  
  file '/path/to/file10.mp4'
  
  file '/path/to/file11.mp4'
  
  file '/path/to/file12.mp4'
  
  file '/path/to/file13.mp4'
  
  file '/path/to/file14.mp4'
  
  file '/path/to/file15.mp4'
  
  file '/path/to/file16.mp4'
  
  file '/path/to/file17.mp4'
  
  file '/path/to/file18.mp4'

  And some lines of output errors :

  [concat @ 0x357e620] DTS 192000 < 229888 out of order
  
  [h264 @ 0x36920e0] top block unavailable for requested intra mode -1
  
  [h264 @ 0x36920e0] error while decoding MB 32 0
  
  [h264 @ 0x36920e0] concealing 2025 DC, 2025 AC, 2025 MV errors in I frame
  
  [h264 @ 0x36b7a80] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36ff440] corrupted macroblock 26 1 (total_coeff=-1)
  
  [h264 @ 0x36ff440] error while decoding MB 26 1
  
  [h264 @ 0x36ff440] concealing 2003 DC, 2003 AC, 2003 MV errors in P frame
  
  [h264 @ 0x371af40] concealing 1456 DC, 1456 AC, 1456 MV errors in P frame
  
  [h264 @ 0x3736a40] ref 5 overflow
  
  [h264 @ 0x3736a40] error while decoding MB 1 1
  
  [h264 @ 0x3736a40] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3752520] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x376dfa0] P sub_mb_type 8 out of range at 2 1
  
  [h264 @ 0x376dfa0] error while decoding MB 2 1
  
  [h264 @ 0x376dfa0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x37a55a0] ref 6 overflow
  
  [h264 @ 0x37a55a0] error while decoding MB 3 1
  
  [h264 @ 0x37a55a0] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x3789aa0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame
  
  [h264 @ 0x36b7a80] ref 5 overflow
  
  [h264 @ 0x36b7a80] error while decoding MB 4 1
  
  [h264 @ 0x36b7a80] concealing 2025 DC, 2025 AC, 2025 MV errors in P frame
  
  [h264 @ 0x36920e0] concealing 1449 DC, 1449 AC, 1449 MV errors in P frame

• rails / streamio-ffmpeg - How to execute 2-pass encoding ?

  20 mars 2017, par R4ttlesnake

  I’m using streamio-ffmpeg to encode videos uploaded to my Rails application via ffmpeg. I want to encode the videos to .webm-format using the VP9 coding format and the VP9 Encoding Guide of the WebM Project recommends using 2-pass encoding. I managed to get the videos encoding via streamio-ffmpeg using 1-pass encoding, but I can’t figure out how to handle the 2-pass encoding.

  Here my setup so far :

  # create two tempfiles for the video and a still
  
  video = Tempfile.new(["video", ".webm"], binmode: true)
  
  still = Tempfile.new(["still", ".jpg"], binmode: true)
  
  
  
  # new FFMPEG
  
  movie = FFMPEG::Movie.new(original.path)
  
  
  
  # extract still from video
  
  movie.screenshot(still.path)
  
  
  
  # encode video
  
  options = %w(-c:v libvpx-vp9 -b:v 1000K -threads 8 -speed 4 -tile-columns 6 -frame-parallel 1 -auto-alt-ref 1 -lag-in-frames 25 -c:a libvorbis -b:a 64k -f webm)
  
  movie.transcode(video.path, options)

  The command to do a 2-pass encoding with ffmpeg would be :

  ffmpeg -i <source> -c:v libvpx-vp9 -pass 1 ... -f webm /dev/null
  
  ffmpeg -i <source> -c:v libvpx-vp9 -pass 2 ... -f output.webm
  
  </source></source>

  In particular, I don’t get how to pass the file of the first encoding step to the second step with streamio-ffmpeg. How would I apply these two steps to the syntax of movie.transcode(output, options) ?

  Thanks !