[FFmpeg-user] Always get very large files when I convert

[Andy Civil]

On 2011-06-04 10:26 PM, Lee Gold wrote:
>
> When I convert an mpeg-4 (or most any file type) to an flv I notice the
> flv files are much larger. For example the mpeg-4 might be 40mb and the
> resulting flv is 210mb. This is really a big difference! I do want the
> flv files to be every bit as good in quality as any source file I
> convert from. I use:
>
> ffmpeg -i input.mp4 -sameq -ar 44100 output.flv
>
> This has worked well for every file type I have tried. But would
> appreciate if someone could explain the reason for the  large file sizes
> that result.
>

Unfortunately, "sameq" does not mean 'same quality' as presented on the 
documentation page, this is a myth that started on the documentation page (it's 
still there) and spread throughout the Internet: it means 'same quantizer'. Take 
out the "-sameq" and use instead "-crf <float>" choosing an appropriate value by 
experimentation. (I suggest reducing the file size until you can see a quality 
problem, then backing off to maintain a margin of error.)

-- 
Andy