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

[Bogdan Lotko]

Hello Carl Eugen,

Thank you for the answer.

the console output looks kike this:

bogdan at SLES11:~> /opt/ffmpeg-2.2.1/bin/ffmpeg -f x11grab -s 1920x1200 
-framerate 30 -vb 2000k -i :0.0 output.avi
ffmpeg version 2.2.1 Copyright (c) 2000-2014 the FFmpeg developers
   built on Apr 26 2014 09:48:05 with gcc 4.3 (SUSE Linux)
   configuration: --prefix=/opt/ffmpeg-2.2.1 --disable-yasm 
--enable-x11grab --enable-gpl --enable-libx264
   libavutil      52. 66.100 / 52. 66.100
   libavcodec     55. 52.102 / 55. 52.102
   libavformat    55. 33.100 / 55. 33.100
   libavdevice    55. 10.100 / 55. 10.100
   libavfilter     4.  2.100 /  4.  2.100
   libswscale      2.  5.102 /  2.  5.102
   libswresample   0. 18.100 /  0. 18.100
   libpostproc    52.  3.100 / 52.  3.100
[x11grab @ 0x9233e60] device: :0.0 -> display: :0.0 x: 0 y: 0 width: 
1920 height: 1200
[x11grab @ 0x9233e60] shared memory extension found
Input #0, x11grab, from ':0.0':
   Duration: N/A, start: 1398759630.081104, bitrate: N/A
     Stream #0:0: Video: rawvideo (BGR[0] / 0x524742), bgr0, 1920x1200, 
-2147483 kb/s, 30 tbr, 1000k tbn, 30 tbc
Output #0, avi, to 'output.avi':
   Metadata:
     ISFT            : Lavf55.33.100
     Stream #0:0: Video: mpeg4 (FMP4 / 0x34504D46), yuv420p, 1920x1200, 
q=2-31, 200 kb/s, 30 tbn, 30 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo -> mpeg4)
Press [q] to stop, [?] for help
[swscaler @ 0x9222040] Warning: data is not aligned! This can lead to a 
speedloss
frame=  228 fps= 10 q=31.0 Lsize=    2849kB time=00:00:22.46 
bitrate=1038.8kbits/s
video:2828kB audio:0kB subtitle:0 data:0 global headers:0kB muxing 
overhead 0.758680%

As I wrote I'd like to use it for presentation so the video will be 
played on Windows.
My goal is just to produce a video with acceptable quality, so I'll be 
very pleased if you could give ma a kind of cook-book instruction how to 
do it.

Thank your for your help

regards,

Bogdan

On 04/29/2014 09:26 AM, Carl Eugen Hoyos wrote:
> Bogdan Lotko <boguslaw.lotko <at> chello.at> writes:
>
>> ffmpeg -f x11grab -r 30 -s 1920x1200 -vb 2000 -i :0.0
>> -threads 0 output.xxx
> Complete, uncut console output missing.
> (-threads 0 is the default)
>
>> With some exceptions (last command and mp4 output file)
>> I've got usable output files, but the quality was a
>> big problem: blurred pixels
> If you encode to pix_fmt yuv420p you get blurring, if
> you encode to rgb (or yuv444p) with x264, you get files
> that only FFmpeg (-based software) can decode.
>
> Carl Eugen
>
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>


-- 

*Bogdan Lotko*

b.lotko at chello.at
Phone: +43 1 2852458
Mobile: +43 676 6615012