[mythtv-users] Transcode blues...

[Joe Silver]

> On 11/26/06, Michael Tiller <michael.tiller at gmail.com> wrote:
> > I've never used transcoding in MythTV (automatic or otherwise) but
> because I
> > recently got an HDHomerun I am now dealing with two issues that, it
> would
> > seem, would benefit from transcoding.
> >
> > The first is that I can now get HD.  For the time being, I cannot view
> HD
> > (still working on XvMC, etc but no joy so far).  What I'd like to do in
> the
> > meantime is trancode things down.  I thought this would be simple.  Just
> > setup a transcoding profile (I used the High Quality one) to transcode
> to
> > 720x480.  I used a bit rate around 3800 and left pretty much everything
> else
> > the same.  I used this to transcode an HD program.  The results were
> > terrible.  First, the file size went from 7Gb to 6.6Gb.  This despite
> the
> > fact that I was transcoding from MPEG2 to MPEG4?!?  The picture quality
> was
> > pretty bad (in spite of this) and, finally, the playback was
> jerky.  This
> > seems like such a straightforward thing, how did I screw it up?
> >
> > The second is that I can now get SD broadcasts as well.  However the
> audio
> > is AC3.  Unfortunately my MediaMVPs can't play this (even though mvpmc
> says
> > it supports AC3).  So I thought I would simply do some kind of
> MPEG2->MPEG2
> > transcoding switching the audio to MP3.  But this doesn't seem to be an
> > option.  If I want to transcode it seems like I can only trancode to
> MPEG4
> > or RTJpeg (?).  But those won't play on the Media MVP.  Am I correct in
> > saying that there is no support for MPEG2->MPEG2 trancoding?  I could
> swear
> > I've seen people talk about that before?!?  Ideally I'd like lossless
> video
> > trancode ( i.e. strictly AC3->MP3 transcoding).
> >
> > Oh yes, and lastly I would like to try and save space by transcoding
> some of
> > the movies I have down in MPEG2 to MPEG4.  I've tried this with mixed
> > results.  Often the transcoding bombs out with an error status of 0 (is
> that
> > an error status?!?) or 255.  Where do I look to find out more details
> about
> > why the failure occurred?  Also, while successful commercial flaggings
> > appear in the jobs queue window in MythWeb, it doesn't show successful
> > transcodings (only unsuccessful ones) which makes me a big nervous.
> >
> > Any pointers would be very much appreciated.  Thanks.
> >
>
>

I just tonight found a post with a link to some hd transcoding tips.  they
might be useful:
http://www.myhdbox.com/mythtips/

i haven't tried these exact profiles yet, but they're pretty close to what
i've had been doing to play back transcoded HD on an xbox frontend.  i was
doing essentially the 'resize med' profiles and using mp3 for the audio.  i
use an identical profile for SD transcoding with an exception of changing
the resolution to 512x384.

good luck.
JS
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