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I've been trying to figure out an ffmpeg command with following requirements while converting 'avi' to 'mp4' with H264 video codecs. One command I tried was generic one like this which is recommended on most forums.

ffmpeg -I input.avi -acodec copy -vcodec copy output.mp4

But this copies same video codec & doesn't convert to H264. Can anyone of you guys help me compose a line of code that would do the task with following requirements.

=> Video Options

Codec: H264 Video  Aspect  Ratio: No Change Video  Resolution: No Change Video  FPS: No Change

=> Audio Options

Codec: AC Audio  Channels: No Change Audio  Frequency: No Change Audio  Normalization: No Change

Thanks in advance!

  • 1
    -c:v libx264 ? (i.e. instead of -c:v copy, also -c:v is the same as -vcodec)
    – grochmal
    Aug 13 '16 at 22:10
  • @grochmal thanks friend, I'll try this now & give my feedback to you soon.
    – Sollosa
    Aug 14 '16 at 7:18
  • @grochmal it didn't work really, says 'error while opening encoder for output stream #0.0 - maybe incorrect parameters such as bit-rate, rate, width or height'
    – Sollosa
    Aug 14 '16 at 7:34

Let us enumerate the parameters to ffmpeg then.

  • -acodec is better written -c:a (menmonic codec for audio)
  • -vcodec is better written -c:v (same mnemonic)
  • -i is the input file (not -I)

ffmpeg does a pretty good guesswork based on file extensions, therefore doing:

ffmpeg -i file.wem file.mp4

Will convert things, but probably in a pretty poor quality.

For H264 you are after the libx264 codec therefore it should go:

ffmpeg -i file.avi -c:v libx264 -c:a copy file.mp4

As a test let's use the classic webm example:

$ wget http://video.webmfiles.org/big-buck-bunny_trailer.webm
$ ffmpeg -i big-buck-bunny_trailer.webm -c:a copy -c:v libx264 bbb.mp4
$ ffprobe bbb.mp4
    Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'bbb.mp4':
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf57.41.100
  Duration: 00:00:32.50, start: 0.000000, bitrate: 414 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x360 [SAR 1:1 DAR 16:9], 341 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
      handler_name    : VideoHandler
    Stream #0:1(eng): Audio: vorbis (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 64 kb/s (default)
      handler_name    : SoundHandler

And that looks promising, stream #0:0 is a H264 encoded video stream.

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