[mythtv-users] Transcoding SD MPEG2 to H.264---recommendations?

Chris Tepe cstepe at ctdataservices.com
Mon Nov 29 19:48:01 UTC 2010

On 11/29/2010 1:54 PM, f-myth-users at media.mit.edu wrote:
>      >  Date: Mon, 29 Nov 2010 13:19:03 +0000
>      >  From: "D. R. Newman"<d.r.newman at e-consultation.org>
>      >  On 29/11/10 08:52, f-myth-users at media.mit.edu wrote:
>      >  >  However---the result was unusable.  The activity log was crammed full
>      >  >  of "audio 192 time went backwards 0 ms, dropped 1 frames" and "video
>      >  >  time didn't advance - dropped 1 frames" lines, and about halfway
>      >  >  through the transcode, it suddenly went from claiming it had 20
>      >  >  minutes to go, to done.  (It also said "sync: got 26887 frames, 60691
>      >  >  expected", which might explain a thing or two.)  And the result, as you
>      >  >  might expect, was a jumpy mess.
>      >  >
>      >  >  I have no idea why this didn't work.
>      >  One possibility is that the source file contains lots of errors. I
> I considered that, but c'mon.  It was just a normal PVR-250 recording
> from an STB.  It plays just fine.  It seems unlikely that every other
> frame (on average) has an error in it.
>      >  normally remultiplex everything before conversion. I use ProjectX to
>      >  demultiplex a recording into separate sound and video files, then mplex
>      >  to put them back together, synchronising the sound and video at the same
>      >  time. ProjectX is pretty good at detecting and tidying up errors in
>      >  recordings. I find that this even makes a difference on DVB-T digital
>      >  recordings.
>      >  I actually run ProjectX and mplex from a script (attached). But to do
>      >  that, you need to compile ProjectX to run without a GUI, otherwise it
>      >  tries to pop up an Xwindow owned by mythtv. So you may want to start by
>      >  manually using ProjectX and mplex, then try Handbrake/Avidemux or
>      >  whatever on the resulting file.
> Yeah, if I have to, I'll preprocess, but this seemed surprisingly
> broken, and I'm always wary of breaking up&  rejoining AV precisely
> because I don't want sync errors creeping in.  I may give this a try
> with a LiveCD of a different Ubuntu release or something, in case it's
> this particular version of Handbrake that's broken.
> Or, if anyone has a favorite non-Handbrake set of args for ffmpeg or
> whatever, I'll try those, too.  Handbrake was just the first thing I
> tried, since people often recommend it and it was easy to give it a
> shot, but I have no particular reason to prefer it to any other
> scriptable solution that actually works.
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I may have my codecs wrong but I use these scripts 
(http://www.mythtv.org/wiki/Ipod_export) to export videos for my droid.  
I've adjusted resolution and bitrate for my tastes/filesize.


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