[FFmpeg-user] Poor quality of screencast 1920x1200 on Linux

Carl Eugen Hoyos cehoyos at ag.or.at
Wed Apr 30 09:57:04 CEST 2014

Bogdan Lotko <boguslaw.lotko <at> chello.at> writes:

> ffmpeg -f x11grab -s 1920x1200 
> -framerate 30 -vb 2000k -i :0.0 output.avi

"q=31.0" in your output indicates that the bitrate is 
not sufficient / cannot be reached for some reason.
For maximum quality, remove "-vb 2000k" and use 
"-qscale 2 -mbd 2" instead.

> ffmpeg version 2.2.1 Copyright (c) 2000-2014 the FFmpeg developers

Mostly unrelated:
Please use current FFmpeg git head when asking for 
support on this mailing list.
(2.2.1 is new atm but this will change.)

> As I wrote I'd like to use it for presentation so 
> the video will be played on Windows.

Do you mean "on Windows with (vanilla) WMP" or "on 
Windows with vlc"?
For WMP either use -vcodec msmpeg4 (larger files) or 
"-vtag" - unfortunately I forgot the value, it should 
be either "MP4S" or "MP4V" (XVID should also work).

> My goal is just to produce a video with acceptable quality

Reading your console output, -qscale 2 should increase the 
quality but please understand that all "normal" video 
codecs only support yuv420p and are by definition not 
well suitable for screen capture.
There are alternatives (everything with "rle" and Flash 
screen video) that support RGB but I suspect none of them 
will play on vanilla WMP.
-vcodec libx264rgb is high-quality, high-performance but 
is only supported if the playback software is FFmpeg-based 

Please do not top-post here, it is considered rude.

Carl Eugen

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