MPEG-limitations in AVIdemux?

[Gew]

Hiya!

I had this old music video á MPEG1. I noticed, the seeking was torn every here and there in the video. I thought that it would be messy GOPs or something like that, but thought to try the easy pathway (which actually works.. occasionally ^^) of just re-muxing the whole thingie. So, I launched AVIdemux.

MPEG-PS, save..

"blah blah DVD audio must be 48khz mp2 blah blah.."

The mp2 main audio track was wrapped in 112kbps/44.1khz. Gah. Tried a MPEG2-TS container instead. It worked. Also, the seeking was now in working properly all through the video. However. I couldn't let go, felt annoying/overkill to keep an MPEG1-piece made for local playbacks in a daarn TS-container. Besides, the original was in a MPEG-PS container, so obviously no issue with MPEG-PS, just the Avidemux "newbie locksmith".

I overcame the issue by downloading some proprietary shareware app with a GOP-fix feature, so that I could finally get the darn thing back in it's MPEG-PS; with seeking working properly.

So, now I'm just curious, is there any possibility to "override" this lock in AVIdemux? I've been through the list of switches in the CLI mode, but doesn't even find a way to output .mpg via cli (only .avi dump).

Now, could I have fixed this in avidemux? Was I overlooking something?

[guns1inger]

AVI Demux is configured to encode for DVD, which must have 48kHz audio, even if it is Mpeg-1 source. VCD source must have it's audio re-encoded at 48kHz for use on DVD.

What you probably should have done was select the VCD setting instead, which might not have complained about the audio.

[Gew]

Yeah, but how do I change that setting? When I chose Auto --> VCD from the menu, it changes a/v output settings to (re-encode-like) TwoLAME / mpeg2enc, and like I said, I just want to rewrap it in a new container, not re-encode.

[guns1inger]

If you leave video and audio to Copy, and choose Mpeg video as the container, does it still complain ?

[Gew]

Nope.
But on the other hand, then it will discard the audio track instead.

[jagabo]

TMPGEnc Free's MPEG Tools can demux and remux VCD MPEG 1 and 44.1 KHz MP2 audio.

[AlanHK]

VCDGear is freeware with some useful features.
Try "mpeg -> mpeg" with "Fix MPEG errors" selected.

[Gew]

Thanks for the tips. I've tried mentioned software and it all seems like great apps. However, the seeking issue seems tied to GOP malfunction rather than a simple container header issue. It's sort of off-topic I know but.. Is there any GPL/freeware equivalence to the GOP-fixer feature in Womble MPEG-VCR?

Womble seems to be the only software willing to "heal" these old .mpg's so that seeking works properly, but it's proprietary-ware, something I don't like. I tried ticking the "fix MPEG errors" box in VCDGear but it just won't cut it. Any other idea?

[minidv2dvd]

restream can fix gop problems, but it's for mpeg-2. not much call for mpeg-1 these days, and tools are kind of scarce.

[Gew]

Thanks for the tips on restream. It may come in handy (later on) when it comes to MPEG2 files, so I'll add it to my tools-folder!

Anyways.
I think I found a [freewarisch] solution on this GOP-mess-on-MPEG1-files deal. First I demuxed the file, then I loaded the video stream in a neat piece of app called "MPEG Sequence Maker" (found it by further searching on this site). I pulled a GOP-remake on the video, and then muxed the output and the original .mpa stream together using good ol' ImagoMPEG-muxer. The result was a blast!