M2T vs MP4

trojanrobmc wrote on 5/10/2010, 12:33 AM

Question:

What are the pros and cons of rendering your videos shot in AVCHD format as M2T vs MP4? It looks like MP4 takes up only about 80% of the space that a M2T file does. Which format delivers better quality?

Comments

PeterDuke wrote on 5/10/2010, 4:35 AM

If the underlying codec is MPEG4 AVC aka H.264 in both cases, then I would have thought that the quality would be the same direct function of the bit rate. In other words, the bigger the file the better the quality. No doubt the two containers have different overheads but that should be minor.

I have no first hand knowledge, just theorizing.

MPM wrote on 5/11/2010, 5:39 PM

M2T -> http://www.fileinfo.com/extension/m2t

mp4 is a variant of mpg4, but beyond that can mean a whole lot of different things. Just going with the AVC variant there are loads of settings that can make the result compliant or not with whatever spec.

FWIW... mpeg4 is later than mpeg2 so it offers more advancements, is more efficient etc. It also takes more horsepower & time to code & decode. Which codec or format you use is normally dictated by what you want to do with the video, the space available, the quality of the original etc. If you encode to BD compliant AVC at X bit rate, then encode to BD mpg2 at the same bit rate, the files will be about the same size -- however AVC can pack more quality into that same sized file, *If* that extra quality is there to begin with in the source.