Monday, August 13, 2007


In todays mobile phones the 3GPP standard is widely in use for videos on the phone. But what is 3GPP? The video is encoded in H.263 and the audio in narrow-band AMR (adaptive multi-rate) audio codec.

H.263 is a next of kin to MPEG4. The real difference for files in this format which is usable for cell phones in audio format. 3GPP use AMR mono, MPEG4 use MP3 audio in stereo. In addition 3GPP has a limit in bit rate. So, if your phone allow to play MPEG4 video - don't use 3GPP. The way to convert video files in MPEG4 format is easy. Do like this:
# ffmpeg -i myvideo.mpg -ss 00:00:00 -t 00:00:30 \
-vcodec mpeg4 -acodec aac -s qcif -r 15 myvideo.mp4
  • -i input file
  • -ss seek time
  • -t finish time
  • -vcodec video codec
  • -acodec audio codec
  • -s size of picture
  • -r frame rate (don't use too high)
And keep attention, sometimes in the internet people rename MPEG4 files with audio stereo channel into 3GGP format. So, in reality it is not a 3GPP.


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