[mythtv-users] Transcoding 101

Jon Bishop jon.the.wise.gdrive at gmail.com
Mon Aug 4 04:06:43 UTC 2008

On Aug 1, 2008, at 2:51 PM, moodyjunk at frontiernet.net wrote:

> Before going through the bother of setting up transcoding I need some
> basic information comparing MPEG-2 to MPEG-4 and can't seem to find it
> on the web.  I'm all for saving space, but I want a loss-less  
> recording.
> 1) Does transcoding from MPEG-2 (HD cable) to MPEG-4 reduce the
> quality of the recording?
> 2) How much space does it save?  10%, 50%?
> 3) Can MPEG-4 recordings be played via MythTV Watch Recordings?

I have been saving Nova episodes for a while now. I noticed that the  
HD signals were eating up quite a bit of my hard disk space (5 gigs a  
piece, only have a 200gb drive at the moment. That's another issue  
though) and decided to try a transcode of one to see if I could find  
some acceptable settings. I created a new transcoder profile, and set  
it to encode to xvid using 2200 for a bitrate, mp3 for audio (using  
the highest audio quality possible == setting to 1) and resized to  
(Auto width) x (640 height).

This made my 5 gig file into a 640 meg file, and though video isn't as  
crisp, the picture is more than acceptable for my SD CRT television. I  
don't know what it will look like on a high def. display. After  
transcoding, it keeps it in my recordings list, just as if it was a  
fresh record. I've set the nova's to automatically transcode upon  
completion by default now.

You may want to test transcode settings before you make up your mind,  
but this setting works for me.


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