[MPlayer-users] (Re-)Encode to all I-Frames?

Vladimir Mosgalin mosgalin at VM10124.spb.edu
Wed Mar 11 20:52:32 CET 2009

Hi Hibiki Kanzaki!

 On 2009.03.11 at 12:16:54 -0700, Hibiki Kanzaki wrote next:

> (how) Can I re-encode a video file/stream so the output
> is all I-Frames, and, where the concept of "GOP" applies,
> every GOP has exactly one frame?

Yes, you have to use mjpeg codec in libavcodec (assuming you want some
lossy compression) or mpeg4 codec with "keyint=1" option. It should be
also possible with xvid and x264 but i haven't checked if it works.

Now if you want loseless compression (or no compression) there are more

Remember that you need to increase your bitrate A LOT for mjpeg or mpeg4
with keyint=1 compared to original video, or video quality will drop a
lot. With mjpeg you can't use vbitrate option, use vqmin/vqmax or
vqscale instead.

Altered examples from mplayer manpage:
mencoder dvd://2 -chapter 10-15 -o title2.avi -oac copy -ovc lavc -lavcopts vcodec=mjpeg:vqscale=2

mencoder dvd://2 -chapter 10-15 -o title2.avi -oac copy -ovc lavc -lavcopts vcodec=mpeg4:keyint=1:vbitrate=15000



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