[FFmpeg-user] output jpeg quality
lou at lrcd.com
Mon Jan 12 19:08:20 CET 2015
On Sat, 10 Jan 2015 23:21:42 -0800
Green Koopa <greenkoopa at gmail.com> wrote:
> This creates one image for each second of video:
> ffmpeg -i 00020.MTS -vf fps=fps=1 -f image2 stills-%03d.png
> When I change the output format to jpeg, it does the same:
> ffmpeg -i 00020.MTS -vf fps=fps=1 -f image2 stills-%03d.jpeg
> But there is a problem. The quality of the jpegs begin okay, but quickly
> deteriorate. By the tenth image or so, they are unusable. This seems
> strange to me, but this is my first day with ffmpeg.
Does it look better if you use -qscale:v (or -q:v)? It's a linear scale
of 1-31. A doubling of the value will probably (very) roughly halve the
bitrate. 2-5 are good values to try, but you can experiment.
You don't need the "-f image2".
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