[mythtv-users] 68% filesize increase after transcode!

Mark Kundinger mkundinger at yahoo.com
Sun Sep 25 06:39:58 UTC 2005


I don't recall the default settings for MPEG-4, but it's all about the
bitrate you select.  If you want the transcoder to shrink file sizes,
you're going to need to select a bitrate less than the bitrate of the
source recordings.  The default bitrate is probably pretty fat.

Also, be aware of the "scale bitrate to frame size" option, which will
actually change the bitrate if you're using lower or higher res
captures.



--- Greg Grotsky <spikeygg at gmail.com> wrote:

> Dave, I tried transcoding the same episode to MPEG4 and it came out
> 40%
> larger than the original MPEG2 transmission. I don't know why anyone
> would
> use these methods if they want to keep their videos the same
> dimensions as
> they are broadcast, since it looks like they actually ballon in size
> instead
> of shrink. :( I guess if I was scaling them down as well I'd see a
> size
> decrease but is it worth it?
> 
> Both the 68% increase and 40% increase were seen using the default
> settings
> for both RTJPEG and MPEG4 screen settings.
> 
> Are you using the default settings?
> 
> Thanks,
>  -Greg



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