Inserting MPEG Sequence Headers with TMPGEnc

[vitualis]

Good day all.

Introduction
For those who don't know, regular MPEG Sequence Headers are required for entrypoint placement for VCDs. Entrypoints are in turn needed to make "chapters" for VCDs. For more specific details: http://www.michaeltam.com/chapters.html

Now, this wouldn't be an issue if MPEG encoders automatically placed an MPEG Sequence Header before each GOP header, but they not necessarily do. For example, the Panasonic MPEG Encoder does not. TMPGEnc does on the VCD template, but unless you know about this issue, you may forget to set it to do so for a custom XVCD encoding (Settings --> GOP Structure --> Output Interval of Sequence Headers = 1).

Now, although you can use the MPEG Sequence Maker tool as detailed in the above link, you can actually use TMPGEnc to insert sequence headers as well...

The Method

1. Download and install TMPGEnc.
2. File --> MPEG Tools --> Cut and Merge
3. Change the type to "MPEG-1 Video-CD" for standard VCDs or "MPEG-1 Video-CD (non-standard) for XVCDs
4. Add the clip that you want to have sequence headers inserted into.
5. Browse for a new output save file
6. Run.

That's it!

What appears to happen
With the Cut and Merge tool, TMPGEnc first extracts the video stream and then the audio stream and then remuxes them.

I think that when TMPGEnc extracts the video stream, it resets the MPEG Sequence Headers. This is logical as during a "cut" (even though we aren't cutting anything), the video clip timings in the sequence headers need to be reset (e.g., if I cut at 40min, the 40min mark of the second clip is now 0 minutes).

Just using the multiplexing tool in TMPGEnc will not change the sequence header status.

I've verified that sequence headers are indeed inserted with a number of tools (MPEG Sequence Header and VCDImager Tools GUI / VCDXMINFO). And, the proof is in the product. You can make functional chapters with the subsequent clip where you couldn't before.

Problems / Issues
Using TMPGEnc in this manner is much more simple and quick compared to demux, run elemental video through MPEG Sequence Maker and then remux. However, I've found that TMPGEnc sometimes (randomly apparently) will cause an audio squawk at the end of the video if the CUT and MERGE tool is used in this manner.

In such a case, the older MPEG Sequence Maker method can be used as a fallback.

BTW: entrypoints can only be placed where there is an MPEG Sequence Header and an MPEG Sequence Header can only be placed before a GOP header (which necessitates a new GOP). For those encoding with TMPGEnc on the open gops setting (just about everyone), the possible entrypoints can sometimes be surprisingly sparse (seconds apart). The fix for this is to used the closed gops setting (possible decrease in video quality) or use TMPGEnc to force intra frames at specific framenumbers (though this requires planning of chapter placement PRIOR to encoding).

Regards.

[Lua]

TMPGEnc does on the VCD template, but unless you know about this issue, you may forget to set it to do so for a custom XVCD encoding (Settings --> GOP Structure --> Output Interval of Sequence Headers = 1).
Regards.

does anyone know if TMPGE does the sequence headers for svcd?

The Method
Download and install TMPGEnc.
File --> MPEG Tools --> Cut and Merge
Change the type to "MPEG-1 Video-CD" for standard VCDs or "MPEG-1 Video-CD (non-standard) for XVCDs

and svcd is in which category? VCD or XVCD?


thanks!
take care.

[vitualis]

Yes it does.

Regards.