[FFmpeg-user] Help with transcoding a vid from 1280x720 to highest quality HD 1920x1080
barsnick at gmx.net
Mon Mar 21 16:51:40 CET 2016
On Sun, Mar 20, 2016 at 11:36:17 -0600, jd1008 wrote:
> highest quality HD 1920x1080
You should know better by now to be more specific. E.g. do you have any
restriction when it comes to codec? Time to convert? File size?
The best quality with the smallest effort can indeed be achieved if you
let the player/client rescale. I know that some rescalers are bad (I
own at least one :-P), so you may have a reason.
Rescaling on source level implies reencoding. "Highest quality" can
strictly only be achieved if you re-encode to a lossless codec (or
codec variant), at the cost of large files/large bandwidth. does your
client even understand lossless codecs? Are you okay with large
Even if "lossy" is okay, to achieve similar quality (despite no
information being added when upscaling), you need more bandwidth than
the original. You will have to experiment what fits your need.
All those caveats aside:
$ ffmpeg -i EarthView.mp4 -vf scale=hd1080 -c:v libx264 -c:a copy EarthView.large.mp4
If the quality is not sufficient, add "-crf NN" as output (codec)
option, and choose a smaller number for NN than the default 23.
I could give better advice if I knew what you were aiming for...
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