[mythtv] MythArchive bugs and "fixes"

Paul Harrison mythtv at dsl.pipex.com
Wed Oct 22 22:07:24 UTC 2008

Martin van Es wrote:
> Hi,
> I'm using MythTV together with an hauppauge pvr-500 and recently
> upgraded to 0.21-fixes (svn).
> First of all I'd like to congratulate you all on the achievements in
> this "release". Silent tuner failover when watching live-tv is a
> blessing, fill zoom for watching movies (using Internal player instead
> of mplayer) is sweet!
> After upgrading I thought I'd give MythArchive a try but it failed. It
> turns out several things are broken (for me) and following are the
> fixes needed to make things work:
> 1. mythreplex fails because the audio stream was not correctly
> detected by mythburn.py. After some debugging it turns out that
> mytharchivehelper writes lower-case types in the streaminfo.xml, but
> mythburner.py strictly looks for AC3 and MP2 (capitals). As a result,
> no valid audio stream is found and the demux fails. Changing all
> capital references to lowercase ones in mythburner.py fixed this
> problem.
Are you sure about that? The first thing mythburn.py does in 
selectstreams() when reading  the  codec from the info  file is:-
 format = string.upper(node.attributes["codec"].value)
in other words it converts the codec to uppercase and it is that that is 
stored in the audio1 and audio2 tuples that are passed to all the other 
functions where it's needed.
> 2. After getting mythreplex to start without failure, it runs endless
> (or so it seems). It turns out it tries to append an extra frame in
> the audio stream so often that the mythburner.log file quickly became
> larger than the movie it was trying to demux. After some googling I
> found m2psd, which is tailor made to demux pvr-150/250/350 mpeg2
> streams. Perfect for the job, I thought.
> I created a little wrapper script that generates the demuxed streams
> and renames them so that mythburner.py can find them afterwards:
> m2psd.sh
> #!/bin/sh
> /usr/bin/m2psd -a $MPG2FILE $BASENAME
> # Rename files for further mytharchive processing
> mv ${BASENAME}-0.mpa ${BASENAME}0.mp2
> mv ${BASENAME}-0.mpv ${BASENAME}.mv2
> 3. In mythburner.py I changed deMultiplexMPEG2File() function to
> generate the demux command like this:
> command = "m2psd.sh %s %s" % (mediafile, folder + "/stream")
Personally I've never had any problem with  mythreplex but  I know it 
can break the audio sync for a few people. This is the first I've heard 
it  looping endlessly though.  The script also supports using projectx 
as an alternative to using mythtranscode/mythreplex. Did you try that?

m2psd looks interesting but unfortunately it's not a real replacement 
for mythreplex though, doesn't support TS streams for one thing and it 
doesn't look like you can select which audio stream you get.
> After these changes, I was able to sucessfully create a DVD iso from
> several recordings. (4. Actually I missed mkisofs because debian wants
> people to move on to genisoimage, but after installing the deprecated
> mkisofs transition package which creates a symlink to genisoimage, all
> went smooth and well).
> I'm not saying these changes should make it into mytharchive, I just
> wanted to give an impression of my experiences and solutions to the
> problems I encountered.
> Hope they may be of any help in understanding the problems a generic
> pvr-500 user may (will?) experience using mytharchive in 0.21-fixes.
> Grtz
> Martin

Paul H.

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