MPEG1 demux/remux problem

[jadran]

In order to try to put my downloaded US TV shows on a DVD to play them on my standalone DVD player (does not support ISA files), I tried to transcode the audio to 48000 (using every How-to-Guide from this site).

But, even if I just demux and remux the file without transcoding to 48000 - I get sync problems (tried to demux to mp2 and wav files).
Noticed that the audio and video files are of different playing lengths (ca. 3 sec/40 min playing time) when I play them alone.

Tried TMPGenc, VirtualDub, SVCD2DVDMPEG.
Tried TMPGenc DVD Authoring Tool, DVDit! PE, Ulead Movie Factory, Sonic Solutions.

Could it be that's because I am in Europe and the shows are from the US (50Hz vs. 60 Hz)?

Any idea how I could demux so that the files are of the same playing length?

Thanx for any suggestions.

Jadran

[mats.hogberg]

Could it be that's because I am in Europe and the shows are from the US (50Hz vs. 60 Hz)?

More likely due to frame rate differences (23.976 vs 25 fps) but enen so, there's no frame rate conversion involved in a simple demuxing?!? What format is your source file, and what do you want as your end product?

/Mats

[jadran]

File Info of the source file from VirtualDub:

Video track: frame size, fps (µs per frame) 352x240, 29.970 fps(33367 µs, bitrate 1150Kbps
Audio track: 44KHz stereo, 224 Kbps Layer II, # of frames 98534
I'd settle for any end product variant (NTSC/PAL, with the same frame size, fps).

But as you point it out - how could it be that simple demux/remux causes sync problems is beyond my understanding? This even without transoding 44KHz to 48KHz.

I am most likely making some stupid newbie mistake but I do not know which.

For instance, I start a new project in TMPGenc, choose NTSC DVD (tried also NTSC VideoCD 29.97fps) and do demux/remux and the sync problem is there.
I do not even try to convert to PAL (25fps) to have as few changes as possible.

Jadran

[mats.hogberg]

Seems like a std NTSC VCD mpeg. If the "out of sync" is constant, just add some silence at the start of the audio (if the audio is too early, as it usually is).

In this case, the problem is caused by that the original is muxed with skew - the audio starts later than the movie track, like this:
| AAAAAAAAAA
|VVVVVVVVVVV
When you separate them, and then mux them, it becomes:
|AAAAAAAAAA
|VVVVVVVVVVV

If it's a gradual drift, I can't understand why, but maybe can be compensated for by stretching the wav to make it the same duration as the movie?

Once you have it resampled, you can author it as NTSC DVD without further processing.

/Mats

[FOO]

For instance, I start a new project in TMPGenc, choose NTSC DVD (tried also NTSC VideoCD 29.97fps) and do demux/remux and the sync problem is there.

TMPGene won't do demux/remux in the main project , and the settings
there are irrelevant to muxing. Dunno what you are doing.

[jadran]

How can I stretch a wav file?
It is a progressive sync problem. and audio is always before the video.

Jadran

[jadran]

What I do is go to TMPGenc/MPEG Tools and do a demultiplex, then when I get two files (*.m1v and*mp2) I use the same MPEG Tool to multiplex the two files back together. This always results in a file which is somewhat bigger then the original/source file and it has a sync problem in which audio is faster than video. The same happens when I use do *.m1v file and multiplex it with a *.wav file of the same source file which I get using VirtualDub.

Jadran

For instance, I start a new project in TMPGenc, choose NTSC DVD (tried also NTSC VideoCD 29.97fps) and do demux/remux and the sync problem is there.

TMPGene won't do demux/remux in the main project , and the settings
there are irrelevant to muxing. Dunno what you are doing.