[mythtv-users] Higher-quality archive to DVD (interlacing)

[Will Dormann]

Hi folks,

I've recently revisited the concept of burning a MythTV-recorded program
to DVD.   In this case it was a long (just over 2 hours) recording.

The first thing I noticed was that mythburn.py would stop with a "MySQL
server has gone away" error after encoding the recording with ffmpeg.
My hunch here is that mythburn.py opens a database connection at the
beginning and re-uses that connection for the rest of its operation.
Since my mythtv box is quite anemic (Atom/ION), it can be over 12 hours
for a 2-pass encoding of an HD h.264 recording.   My workaround was in
my /etc/mysql/my.cnf to specify:

connect_timeout         = 100000
wait_timeout            = 100000

I'm not certain if both are required though.


The other thing is that cutlists still don't work with HD-PVR (h.264)
recordings.  So I'm using my old patch still:
http://lists.mythtv.org/pipermail/mythtv-users/2014-May/363676.html


Now on to the issue in the subject.  Due to a glitch in the recording
itself, the DVD that mytharchive produced a DVD that was only about 48
minutes.  So I investigated an alternative: avstodvd
<http://sourceforge.net/projects/avstodvd/>

When comparing the mytharchive-produced vs. the avstodvd-produced
output, it became clear that the former was deinterlaced and the latter
was interlaced.  My source is 1080i, and the ffmpeg route just
re-encodes it which looks to deinterlace it.   While the deinterlacing
seems to look good, the outcome is that the smoothness suffers (to the
picky eye at least).    A 1080i recording displays 59.94 pictures
(frames) per second.   The ffmpeg route throws away half of that
smoothness to end up with a DVD-compatible 29.97 fps.

Now consider the avstodvd scenario.  It uses avisynth split the fields,
resize, and then re-interlace the fields together.  The end result is an
interlaced DVD that has 59.94 pictures per second.

I'm not sure if there's a GNU/Linux equivalent of avisynth is, but I'm
wondering if anybody has put any thought into some way of improving the
quality of produced DVDs through the use of interlacing (when
appropriate)?    Or is the concept of burning recordings to DVD archaic
enough that it's not worth the effort?


-WD