Archive for the ‘ffmpeg’ Category

ffmpeg to transcode XDCAM-EX [.mp4] files to QT-DNxHD

Thursday, December 23rd, 2010

It is possible to use the open-source ffmpeg to transcode XDCAM-EX files to other formats, such as DNxHD.Information from as of 2010-12-23:

  •  ffmpeg -i input.mp4 -vcodec dnxhd -b 60Mb -acodec copy
    • 60Mbit is a 720p bitrate.
  • This is a good ffmpeg for pro users help site:
  • This is the command line I got from Baptiste who is developing the DNxHD stuff in ffmpeg.
    • Progressive:
      • fmpeg -i inputfile.mp4 -vcodec dnxhd -b 185Mb -acodec pcm_s16le
    • Interlaced: (The difference is the -flags +ildct)
      • ffmpeg -i inputfile.mp4 -vcodec dnxhd -b 185Mb -flags +ildct -acodec pcm_s16le
  • And this is a link to a DNxHD white paper:
  • We are thinking of using 36Mbit DNxHD but all people we talk to say to use 185Mbit or maybe 120Mbit and that 36Mbit is for offline.
  • But if you don’t have a problem using allot of GB on disc then go for Max Mbit for the specific resolution and framerate you use:
    • 1080p/25 DNxHD 185 1920 x 1080 8bit 25fps = -b 185Mb
    • 720p/50 DNxHD 175 1280 x 720 8bit 50fps = -b 90Mb
    • 1080i/50 DNxHD 185 1920 x 1080 8bit 25fps = -b 185Mb
  • More settings for other framerates:
    • http://www.itbroadcastanddigitalcine…#Encoding_VC-3
      • Had many commandlines and DNxHD settings, though sadly none for 1080p50 (as I require).
      • …and link is dead – as of 2016-08-18

Information from

  •  FFmpeg is now providing Avid DNxHD (SMPTE VC-3) encoding and decoding features