When is an MPEG not an MPEG?

[Flarch]

I have an MPEG 1 file i received already prepared for VCD. With similar files, i've used VCDBuilder to add a splash and chapters and burned it no problem. To add the chapters i need to preview the file and find where the markers need to go.

> QT reports this file as an unknown format.
> MPlayer plays it fine, but has never been much good for specifying chapters because i can't seek back and forth to find where they need to go. However, it's info window assures me it's MPEG 1 with all the proper VCD perameters.

Here's where ffmpegX comes in.

I thought if i could get some program to manipulate the file, it may correct whatever problem is keeping QT from playing it. I tried to demux it with ffmpegx. As soon as i click "Demux", it dings. Process information shows:
-----------
Skipped -1 zeroes at start of file
mpgtx: AT EOF - please stop me!
mmm, this file does not start with a pack, offset: -1
use the desperate_mode switch as the first option -X to search for a header in the whole file!
if you want to force the operation. May yield to an endless loop if no valid header is found!
Does not even begin with a 00 00 01 xx sequence!
/Volumes/Yang//STTA1/STTAa.mpg is not a valid mpeg file
-----------

I then tried dropping the file on bbDemux. Out popped the .m1a and .m1v files just fine. I tried playing these separately, and QT had no problems with either individual file.

I can use the .m1v file to find my desired chapter locations. HOWEVER, i'm unsure VCDBuilder will like the original any more than QT or ffmpegx.

QT being able to play the streams seemed a good sign so i tried to use ffmpegx to try and mux them back together. Got the instant ding again, and this report:
------------
Input #0, mpegvideo, from '/Volumes/Yang/STTA1/STTAaS224SS0.m1v':
Duration: N/A, bitrate: N/A
Stream #0.0: Video: mpeg1video, 352x240, 29.97 fps
No audio or video streams available
------------

I even saved the two .m1 files as .movs and then tried ffmpegx's "Mux as..." but got:
--------------
Input #0, mov,mp4,m4a,3gp, from '/Volumes/Yang/STTA1/STTAaS192SS0.mov':
Duration: N/A, bitrate: N/A
No audio or video streams available
--------------

Opening the original file in ffmpegx, i get:
VIDEO: mpeg-1, size: 352x240, 29.970 fps, 1150 kbps. AUDIO: mp2, 44100Hz, 224 kbps.

But clicking "Info" gives me an alert.

If i open the .m1v and click "Info", i get:
------------
/Volumes/Yang/STTA1/STTAaS224SS0.m1v
Mpeg 1 Video File
Estimated Duration: 01:09:22.61s
Size [352 x 240] 29.97 fps 1.15 Mbps
------------


I'm just going to go ahead and see what VCDBuilder makes of the original file in a test burn on DVD-RW, but i'm wondering why QT doesn't understand the original while bbDemux and MPlayer had no problem with it.

More relevantly, i'm wondering why QT understands the streams yet ffmpegx and it's tools, although they can tell me what original and streams are and their parameters, why they can't operate on any of them.

[major]

I can use the .m1v file to find my desired chapter locations. HOWEVER, i'm unsure VCDBuilder will like the original any more than QT or ffmpegx.

You should try and see.

QT being able to play the streams seemed a good sign so i tried to use ffmpegx to try and mux them back together. Got the instant ding again, and this report:
------------
Input #0, mpegvideo, from '/Volumes/Yang/STTA1/STTAaS224SS0.m1v':
Duration: N/A, bitrate: N/A
Stream #0.0: Video: mpeg1video, 352x240, 29.97 fps
No audio or video streams available
------------

You must use "Mux as.." to combine m1v and mp2.

I even saved the two .m1 files as .movs and then tried ffmpegx's "Mux as..." but got:
--------------
Input #0, mov,mp4,m4a,3gp, from '/Volumes/Yang/STTA1/STTAaS192SS0.mov':
Duration: N/A, bitrate: N/A
No audio or video streams available
--------------

"Mux as.." can't handle mov files.

But i'm wondering why QT doesn't understand the original

Try to use "fast VCD" preset and reencode your mpg to another clean mpg.