[mythtv-users] MPEG4 bigger than MPEG2?

Tom Hayward esarfl at gmail.com
Fri Mar 9 16:06:12 UTC 2012

On Thu, Mar 8, 2012 at 20:51, Ross Boylan <RossBoylan at stanfordalumni.org> wrote:
> Hi, everyone.  I'm a new user, and am wondering why transcoding is
> making my files bigger.  More specifically, I think I have transcoded a
> file from MPEG-2 to MPEG-4, and it got a little bigger (3.1 vs 2.9GB).

The real question is: Why do you want to transcode? Most HDHomeRun
users don't bother with transcoding. I know I prefer to watch my
recordings in original quality. I only transcode to H.264/MPEG-4 AVC
if I plan to keep a recording forever. I usually let recordings
auto-expire after watching them, so a CPU-intensive MPEG-2 to MPEG-4
transcode is pointless.

With a lossless MPEG2 transcode, you can save some storage without
loss in quality (and it's fast, too). Re-muxing from MPEG2-TS to
MPEG2-PS can save up to 20%. Cutting the commercials usually saves 30%
(assuming 30% of the recording was commercials). These are features of
the mythtranscode utility: http://www.mythtv.org/wiki/Mythtranscode


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