[mythtv-users] MythArchive: No sound on DVD - couple of bugs

David Scammell davescammell at gmail.com
Sat Sep 23 20:57:31 UTC 2006

On 9/23/06, Roy Lofthouse <lofty69 at gmail.com> wrote:
> On 23/09/06, David Scammell <davescammell at gmail.com> wrote:
> >
> > Hi,
> >
> > I found a couple of bugs, one is in the file, silence.mp2, which as you
> > may imagine is silence but for 5 seconds, its encoded at compact disk
> > friendly 44.100Khz, not at DVD friendly 48000Khz. I re-made mine with
> > these commands:
> >
> > arecord -f dat -twav -d 5 /tmp/silence.wav
> > mp2enc -r 48000 -o /tmp/silence.mp2 </tmp/silence.wav
> > su - (password)
> > cp /tmp/silence.mp2 /usr/local/share/mythtv/mytharvice/music/silence.mp2
> >
> > It appeared to be causing errors in the mythburn.log when replexing the
> > video, these may of been harmless, but still a bug.
> >
> > The other bug is more serious at least for me and will account for a
> > proportion of the dvd's with no sound issues. The introductorary videos, in
> > particular file pal_mythlogo_intro.mpg has AC3 sound, unlike the other two 2
> > pal intro's which have mp2 sound. When the final dvd is remultiplexed
> > together the AC3 soundtrack from the intro video is made into the primary
> > audio track on the dvd. The remaining audio on the dvd, for me in the UK is
> > MP2 from the DVB-T telly, gets encoded as the 2nd audio track on the dvd.
> > This results in a dvd that appears to have no sound after the intro videom,
> > unless you know to switch soundtrack. I suspect that its non-standard to mix
> > both types of audio coding on one dvd but I don't know for sure, perhaps its
> > my mplex or perhaps there is another way around this. My quick fix was to
> > copy pal_mythtv_into.mpg over the top of pal_mythlogo- intro.mpg.
> >
> > I haven't read that these bugs have already been found, then again I
> > might of missed them on the lists, i'm not up to date with the svn, about a
> > week adrift.
> >
> > regards
> > dave s
> >
> >
> >
> > _______________________________________________
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> > mythtv-users at mythtv.org
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> >
> >
> > Hi Dave,
> I'm having similar issues, but I've also noticed that the problem of
> having to switch audio tracks is happening to me when doing a lossless mpeg2
> transcode in myth...all the commercials are cut, but when I play the file in
> myth I have to manually switch audio track..not sure if it's this that is
> causing mytharchive to burn the dvd incorrect as well??
> Any chance you can transcode some of your recordings and see if you have
> to switch the audio track afterwards??
> Thanks
> Roy
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> Nick, thanks for that, but I think Myth is getting the track selection
correct in myhtharchive, at least i've not found one that didn't work
correctly today after my two fixes. There are no little voices describing
the telly pictures 'Nora quickly poured the tea' or whatever.

Roy, i've never used the transcoding facility, I used to use projectX to
burn to dvd and used avidemux2 to do the editing, this seems to be better.
So I wouldn't know where to start but I may have a go. Let me ask you
something, you have the same problem with mytharchive? Look at the
mythburn.log file from a failed (quiet) disk, do you have a section that
looks like this:

INFO: Audio ch 0 format: mp2/2ch, 48khz 20bps

or do you have one like this (from memory):

INFO: Audio ch 0 format: ac3/2ch, drc
INFO: Audio ch 1 format: mp2/2ch 48khz 20bps

The first one had only mp2 sound track and worked as expected, the second
was the faulty AC3 encoded intro video and needed the audio track changing.
Try my fix?

dave s
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