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-   -   difference between m2t and mpg (https://www.dvinfo.net/forum/general-hd-720-1080-acquisition/96546-difference-between-m2t-mpg.html)

Henry Grevemberg June 14th, 2007 12:51 PM

difference between m2t and mpg
 
i'm using vlc to capture HDV in it's native m2t, as PPro2 doesn't have this option (only mpg). is there a solid reason to go through this extra step? I've heard that it's better to go with the format on the tape, rather than switching from transport to program stream. also, i can't afford cineform at this time, so i'm rendering to tiff sequences for AE composites and keying. it seems to hold up well, but i'm open to advice/suggestions here.

Steven Gotz June 14th, 2007 09:25 PM

A proper capture is taking the ones and zeros off the tape and putting it on a hard drive.

Some programs name it mpg, or others name it m2t, it doesn't matter. It is all the same.

Ervin Farkas June 15th, 2007 06:03 AM

Still, there are some differences
 
M2T is a transport stream used mostly in broadcast (and of course in our HDV cameras), while MPEG is a program stream. It may be that for some programs it does not matter, but for example VirtualDub cannot handle M2T files - I have to run them first through MPEG Streamclip and convert them to MPEG, then VDub will work with the file. Also, the MPEG saved by Streamclip is about 3-5% smaller, so I assume the M2T file has some additional info embedded. There is definitely no transcoding going on within Streamclip, it goes through the file with lightening speed (practically the speed needed to write the resulting file to disk).

All I found is: Transport stream (TS, TP, or MPEG-TS) is a communications protocol for audio, video, and data which is specified in MPEG-2 Part 1, Systems (ISO/IEC standard 13818-1). Its design goal is to allow multiplexing of digital video and audio and to synchronize the output. Transport stream offers features for error correction for transportation over unreliable media, and is used in broadcast applications such as DVB and ATSC. It is contrasted with program stream, designed for more reliable media such as DVDs. (Wikipedia).

Based on this, I would assume the M2T has some additional data for error correction, but I cannot find any more info on this on the internet - can someone with a deeper knowledge enlighten us please?

Henry Grevemberg June 15th, 2007 10:39 AM

i haven't found anything solid on this..
 
i know fcp uses m2t - ppro uses mpg. i hope this is addressed in ppro cs3, that it can capture to either. i'll probably go with the mpg wrapper built into premiere for now, but since i'm setting up the workflow for filmmout, and transfer houses have specifically asked for the m2t variant, i've taken a step back. if they're both the same, is preference for m2t just mac dominated industry jargon?

Steven Gotz June 15th, 2007 06:39 PM

I often capture with Cineform HDLink, or HDVSplit and they both name the files M2T. They can be imported into Premiere Pro and they behave the same as the clips captured in Premiere Pro.

Change the names to MPEG if you wish, or after you capture in Premiere Pro, rename them M2T. It flat out does not matter because the fact that a M2T is supposed to be a transport stream is being widely ignored.


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