any quality lose when merging mpeg2?

[hakeemshabazz]

Is there any quality lose when merging two mpeg2 files together? The files are from the same source, but I want to join them back together, I was just curious if doing this causes the files to be re-encoded to be merged together.

[rcb]

Not if it's a nothing more than a merge. TMPGenc's mpeg tools option can do that nicely.

However, some other apps will insist on recoding - and that will impact end quality.

[hakeemshabazz]

When using the mpeg tools withing TMPGEnc Plus, there is a TYPE setting for MPEG-1 or MPEG-2. If the files (m2v demux'ed from VOB) are from DVD, and I don't want to lose any quality, should I pick the MPEG-2 Program VBR type?

I'm assuming this type will merge the files WITHOUT re-encoding. Am I right?

Thanks for your help.

[teegee420]

You are correct. This might not happen to you, but every time I have tried joining mpeg-2 files with TMPGEnc the merged file had audio sync problems. Now I only use Womble MPEG VCR.

[hakeemshabazz]

teegee420:

do you use womble's AV synch when multiplexing? I was told that the synch problem only happens when the streams you are multiplexing have edited out sections (either the video or audio streams). Which I guess is the case with the whole demux & remux process for most people...

The only thing I am doing is adding fades to the video. I'm doing a few more steps than that to get what I want done, which I guess is causing errors in Womble for me when multiplexing.

I was going to make a post about this, but maybe I'll mention it to you (since you have helped me out in other posts...) After demuxing (with TMPGEnc Plus), I chop the beginning off the the m2v file (about 10 seconds) using mpeg-vcr. Then using mpeg-vcr I add a fade to the 10 sec. clip and save it as its own m2v file with no compression. Then using TMPGEnc Plus again, I merge the two m2v files. Lastly, I remux the ac3 & new m2v. I tried this in Womble, but I get this error:

This file is NOT an mpeg video ES file.

I'm assuming it's because of the merging of the faded clip with the original. Am I supposed to render the faded clip or something? TMPGEnc multiplexes the streams just fine (and it plays fine).

Any ideas?

Thanks alot teegee420

[teegee420]

I do use the A/V sync option in Womble on occasion. It has fixed the problem files every time so far. Regarding your attempt to mux your ac3 and m2v, I don't understand why you got that error. Both ac3 and m2v are elementary streams(ES).

I'm curious why you didn't just open the whole thing with Womble instead of de-muxing in TMPGEnc first.

[hakeemshabazz]

"I'm curious why you didn't just open the whole thing with Womble instead of de-muxing in TMPGEnc first."


I just didn't think of it.