[mythtv-users] Suggested Encoding Rates

Niels Dybdahl niels.dybdahl at gmail.com
Thu Apr 28 18:56:03 UTC 2005

> I noticed the same thing with downloaded files vs. files captured from my
> pvr 150, but even when i use mythtranscode to convert them to mpeg-4, i
> can get downloaded AVI files that look much better and are smaller. Should
> i use one of the external transcoding programs instead of mythtranscode?

A transcoding to MPEG4 from a DVD will give a much better result than
transcoding from a recording from a tuner, because there is less noise
on a DVD.
Downloaded AVI files are often around 1 Mb/s. I transcode to 1.4 Mb/s
which is acceptable quality for me. I also transcode to a resolution
of 480x576 because there is not more information than 480 pixels per
line in a videosignal. If you transcode to 720x576 (or 720x480) you
will loose quality because you use some of the data to preserve
quality that is not there. Some are even transcoding to fewer pixel
per line.

I let my PVR-250 record at 4.5 Mb/s at 480x576 pixels to have a good
recording to start from and then I transcode to the mentioned 1.4
Mb/s. However for some special movies I record at 4.5 Mb/s at 720x576
pixels, which I then store in DVD format.

I guess that you can find an external transcoding program that will
perform better if you let it use more time on it. Nuvexport can f.ex
use a noise filter before transcoding. This should improve quality but
it also takes more time.

Niels Dybdahl

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