fixed

my cards eats only 48000 with this

ffmpeg -f alsa -ac 2 -ar 48000 -i hw:0,0 -s 1024x768 -f x11grab -r 30 -i :0.0 -acodec pcm_s16le -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.

works note ar 48000

with this

ffmpeg -f alsa -ac 2 -i hw:0,0 -s 1024x768 -f x11grab -r 30 -i :0.0 -acodec pcm_s16le -vcodec libx264 -vpre lossless_ultrafast -threads 0 output.

nope