I have been trying to get qscale to work in ffmpeg but I always get the same size of output file no matter what value I give for qscale. Is qscale codec dependent or maybe I am doing something wrong, my ffmpeg is ffmpeg version 0.8.6-6:0.8.6-0ubuntu0.12.10.1.
The following is how I have been testing, the input file is flv but I have also used vob files for the input and always the same result.
In the above example a qscale of 1 and 10 produces identical output files in size and bitrate, I have assumed that increasing the qscale value should give a reduced bitrate in the output file, is my assumption correct.
ffmpeg -i input.flv -vcodec libx264 -qscale 1 -acodec ac3 -ac 2 -ar 48K -ab 224K -async 1 output.mkv