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

George Nassas gnassas at mac.com
Sat Sep 24 21:44:39 UTC 2005


On 24-Sep-05, at 12:38 PM, Greg Grotsky wrote:

> Is RTjpeg not a good compression algorithm?

Depends what you're after - from a compression point of view it's a 
terrible algorithm, from a speed of encoding point of view it's 
terrific. RTjpeg is mostly used by people with frame-grabber cards, 
that is, tv tuner cards that will tune a channel but not encode the 
signal into an mpeg2 stream. Encoding into mpeg can be cpu-intensive 
and hard for software to do in real time so people use the less 
intensive rtjpeg format and then transcode to a much more efficient 
format like mpeg2 or 4 later on.

However, if you already have an mpeg2 file then transcoding *to* rtjpeg 
is a little like transferring your home videos to flammable nitrate 
stock.

- George



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