[mythtv-users] mythtranscode in V31

Stephen Worthington stephen_agent at jsw.gen.nz
Mon Apr 6 02:08:13 UTC 2020


On Sun, 5 Apr 2020 15:08:12 -0400, you wrote:

> I'm biased against MPG or TS files as being
>less compact than MKV (H264) files with similar quality.

You have the wrong idea about MPG and TS files.  They are container
formats - what is inside them is what matters.  In New Zealand, they
contain what is broadcast here, which is H.264, just as you are
putting in MKV files.  Your MKV files are likely more compact for one
or both of two reasons:

1) Your source (broadcast) recording format is not using H.264 inside,
but something that is less efficient (MPEG2 video, for example).

2) You are telling your MKV conversion software to do lossy
compression to a lower bit rate in H.264 than the original file.  So
of course it will be smaller, but also lower quality, both because of
the lower bit rate, and due to the inevitable loss of quality caused
by any lossy conversion process.

If you want the best quality in your MKV H.264 conversions then you
should be using a profile that specifies the best H.264 format that
your playback devices can play.  It is likely that if you are just
using a default setting for the profile that it will be creating a
mid-range H.264 profile like Main at L2.  If you encode in High at L4, for
example, which MythTV can play happily, you get significantly higher
quality for the same bit rate, or a lower bit rate for the same
quality, or some combination of both.  High at L4 is what New Zealand TV
broadcasts use.

See here for some information about H.264 profiles and levels:

https://www.rgb.com/h264-profiles
https://en.wikipedia.org/wiki/Advanced_Video_Coding


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