[FFmpeg-user] last 2 seconds are cut recording screen - hardware aceleration

[Tom Sparks]

On 30/06/2020, Leonardo via ffmpeg-user <ffmpeg-user at ffmpeg.org> wrote:
> Hello,
>
> I'm trying to use ffmpeg to record the computer screen and also audio from
> microfone. Googling I found a lot of "how to". Although I can now record, I
> do have a few questions (3):
>
> 1) Using command
>
> $ ffmpeg -thread_queue_size 512 -f alsa -ac 2 -ar 44100 -i hw:0,0
> -video_size 1024x768 -probesize 10M -framerate 30 -thread_queue_size 512 -f
> x11grab -i :0.0 -c:a aac -c:v libx264 -vf "format=yuv420p" output.mp4

<sniped>

> 3) Are those commands above "correct"? I mean, is there something "wrong" or
> can it be improved to reduce file size, improve video quality or sound
> quality? I know that ffmpeg has tons of options and "improve" is not a clear
> question.

For x264 compressed video use -crf 17see for other options
https://trac.ffmpeg.org/wiki/Encode/H.264

For aac audio compression use -b:a 192k for the bitrate see for other
options https://trac.ffmpeg.org/wiki/Encode/AAC

$ ffmpeg -thread_queue_size 512 -f alsa -ac 2 -ar 44100 -i hw:0,0
-video_size 1024x768 -probesize 10M -framerate 30 -thread_queue_size
512 -f x11grab -i :0.0 -c:a aac -b:a 192k  -c:v libx264  -crf 17  -vf
"format=yuv420p" output.mp4