[mythtv-users] Transcoding 101

[Rod Smith]

On Friday 01 August 2008 05:51:37 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?

Both are lossy formats, so yes, a conversion will reduce the quality. How much 
depends on your settings.

> 2) How much space does it save?  10%, 50%?

That depends on your settings.

> 3) Can MPEG-4 recordings be played via MythTV Watch Recordings?

Yes.

> Just out of curiosity once transcoded do I need to re-commercial flag
> (don't know if the tags are offsets into the files or even direct
> cylinder/head/block addresses)?

I don't believe you need to re-run commercial flagging, at least not if you 
use MythTV's built-in transcoding functions.

-- 
Rod Smith