[mythtv-users] Transcoding to mp4 to reduce file size

jedi jedi at mishnet.org
Sat Nov 10 15:48:19 UTC 2007


On Sat, Nov 10, 2007 at 09:48:55AM -0500, Don Jerman wrote:
> On Nov 10, 2007 9:37 AM, Chris Isip <cmisipster at gmail.com> wrote:
> >
> >
> >
> >
> > On Nov 9, 2007 7:16 PM, Dan Wilson <dwilson at dslextreme.com> wrote:
> > >
> > >
> > >
> > > On 11/9/2007 at 6:31 PM Chris Isip wrote:
> > >
> > > > I'm hitting the limits of my file storage.  I was wondering if there is
> > > > a
> > > > way that I can transcode the mpeg2 programs to mpeg4 and still let the
> > > > videos be viewable in mythtv "Watch Recordings".
> > > >
> > > > Thanks
> > > > Chris
> > > >
> > >
> > > I use the internal transcoding available in myth to convert mpeg2 into
> > mpeg4.  I get about 50% reduction in size, bringing an hour of SD tv down to
> > about 1 GB.
> > >
> > > HTH,
> > >
> > > Dan.
> > >
> > >
> > >
> > >
> > >
> > > _______________________________________________
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> > > mythtv-users at mythtv.org
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> >
> > I was looking more towards a reduction  in size from 1.43  GB to 200 MB for
> > a 1 hour SD show.  I found a ffmpeg formula for transoding to ipod touch and
> > it did just that.  The quality was acceptable for playback fullscreen on my
> > TV as well , but mythtv will not play it ( I tried renaming the transcoded
> > file to the original filename).
> >
> > Has anybody used ffmpeg or mencoder to achieve this.  I'm not really sure
> > what myth thinks the video should be before it can play it.  Theres probably
> > going to be some database edits as well.
> >
> > Thanks
> > Chris
> >
> >
> > _______________________________________________
> > mythtv-users mailing list
> > mythtv-users at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> >
> >
> 
> You can configure your transcoding profile to shrink the video size,
> which will do what you're looking for. It'll also lose some quality,
> but there you go, tradeoffs.  480x480 should cut the size in about
> half without changing the quality much on a SD TV.  After that you'll
> start to see the degradation accelerate.

  I would not recommend altering the resolution, just reducing the bitrate.

  I start out at 6000-9000 mpeg2 and go to 1200 mpeg4. Quality loss is 
neglible. I have more complaints about my video source than my transcoder.
(which is pretty standard for Tivo with "compression" btw)

  A lot of these issues are not unique to MythTV.


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