[FFmpeg-user] Trying to transcode raw video file from VLC

Moritz Barsnick barsnick at gmx.net
Tue Jan 19 00:14:11 CET 2016

On Mon, Jan 18, 2016 at 11:52:15 -0800, no6b at no6b.com wrote:

> Doing some screencaps in VLC but its x264 transcoder is apparently
> broken on Win8.1 x64 systems, including my own. No problem, I figure:
> I'll just save the video in raw format (I'm only capturing a 554x65
> area so even with raw video the file isn't too big) & transcode it to
> x264 using ffmpeg. But no...

You *could* capture with ffmpeg...

But anyway:

> From this point I tried specifying the video frame size with -s, but
> that didn't work. Any ideas as to how to tell ffmpeg how to read
> this, or am I going down the wrong path? VLC says the raw format is
> RV32 & ffmpeg seemed to be able to get the video size correct on that
> 1st try without the -f switch, so the "-f rawvideo" might be leading
> ffmpeg astray?

Hmm. Is it an AVI containing rawvideo, or is it pure rawvideo?

If it's packed in an AVI, the rawvideo parameters should be available
from the container's headers:

$ ffmpeg -f lavfi -i testsrc=size=hd720 -c:v rawvideo -t 3 rawvideo.avi
$ ffprobe rawvideo.avi
ffprobe version N-77840-gcc538e9 Copyright (c) 2007-2016 the FFmpeg developers
Input #0, avi, from 'rawvideo.avi':
    encoder         : Lavf57.21.101
  Duration: 00:00:03.00, start: 0.000000, bitrate: 552980 kb/s
    Stream #0:0: Video: rawvideo, bgr24, 1280x720, 560432 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 25 tbc

If it's an AVI, but that doesn't help - which seems to  be the case for
you - you are looking for the input option "-c:v rawvideo", not "-f
rawvideo" (because "-f avi" would be correct, as automatically detected
or derived from the suffix). I.e. set the codec, not the format
(container) type.

In the latter case (where it isn't really an AVI at all), you need to
tell ffmpeg *all* the codec details. It's described in the rawvideo
format's documentation:

$ [...] -f rawvideo -pixel_format rgb24 -video_size 320x240 -framerate 10

I think this is not the case for you though.


More information about the ffmpeg-user mailing list