How to Add Chapter to Audio Compilation?

alk3997 wrote on 1/10/2007, 2:14 PM

I have a 25-chapter audio compilation that I have been trying to create in Vegas/DVD-A (latest versions for both titles). The audio is AC3 5.1-channel. I used the DVD-A audio montage setup to make the disc and it came out to around 500 MB with a single slide per song.

Everything is fine except for one item. Two of the songs have no break between them. If I use two separate AC3 files then I hear a gap (I assume this is the AC3 metadata header getting in the way). So, I figured the easy way was to make one AC3 file and then add a chapter marker at the appropriate point in the file.

Well, it turns out that function is grayed out, so that isn't available.

After doing some searching, it was suggested that a single DVD movie would be a better choice and sure-enough adding a chapter is very easy.

Unfortunately, while the audio montage produced 0.5GB disc image, using a single DVD movie produced a 5GB disc image. This isn't usable since I'm trying to put a DVD-Audio image on the same disc.

Temporarily what I've done is to go back to a audio/slide montage and added a "dummy" 1 second gap after the two gapless songs, so that the chapter numbers sync-up. But that isn't very a real good long term solution.

So, can anyone tell me how to add a chapter in the middle of a song or provide a hint as to why the montages are so small in file size and yet a video of the same still images is so large? I've tried to look through the optimization settings without finding differences.

Thanks for any help!

Andy

Comments

MPM wrote on 1/10/2007, 4:16 PM

Hope that this will help, but I'm afraid it's a bit general as I've never played with an audio compilation...

Everything you see on the screen from a DVD is an mpg2 video file, whether you produce/encode it or DVDA does it for you. You can control the file size of encoded mpg2 by setting the bit rate -- a bit rate of 5 produces a smaller file than a setting of 8. In addition however [I think thru a loophole in the spec] you can have a still that takes up only a single frame of video yet plays for whatever set amount of time -- think of menus, slide shows etc.

Now AFAIK the trick is to define each of those stills the same way you would a chapter: a longer video is broken up into cells, and chapters are listed in the DVD's IFO files by reference to individual cells. DVDA might not be able to split a cell it's going to create in your case of the comp, though it should be possible after the fact in other software if you're willing to face a bit of a learning curve.

One way that would involve a bit less learning would be to use separate song files and compile in DVDA, then replace the audio track with a version where the songs are joined.

I'm not sure if there's a way to use 5.1 wav or avi files in DVDA to let it compile I assume one long ac3 file.

My first suggestion would be to listen to playback of a DVDA created layout of your project on hdd if you haven't already -- normally don't hear much of a break between ac3 files, & DVDA ac3 playback lags at first.

Otherwise might want to consider re-rendering, editing the source for the ac3 files without the break to give them one.

ScottW wrote on 1/11/2007, 5:33 AM

Couple of observations. There is no loophole in the spec, a cell can have a duration - this is how still menus get created and take up very little space.

The pause between AC3 files is not because of the header - it's because the file is likely not contiguous with the previous file on the DVD, coupled with the fact that the virtual machine had to become involved at the conclusion of the first clip to tell the DVD player the correct thing to do was play the second clip.

My suggestion would be to put 3 songs on the compilation. the first two songs represent the 2 distinct pieces of the music, the 3rd song is the first 2 pieces rendered as one.

--Scott

MPM wrote on 1/11/2007, 9:57 AM

Apologies as probably a bit OT, but may be of interest so...

"There is no loophole in the spec, a cell can have a duration - this is how still menus get created and take up very little space."

The *loophole* part is just something I've read, meaning I think a usage that wasn't originally envisioned when the spec was written -- since I'm not willing nor able to pay the fee for a copy of the spec, which comes with an NDA anyway, I'll never really know, & if I did, couldn't tell ya. ;?P I've read that Play Lists are in the same category, not thought of when the spec was written.

That said, it's correct that cells do have a duration -- in a title vid the cell duration or length is the duration of the piece of video it holds, & besides an optional reference to a chapter number & the cell's (non-opt.) ID, title vid cells are referenced by time. In my experience, & I have only seen a very small fraction of commercial DVDs out there, using still menus is a later development in DVD authoring -- If memory serves (& I may indeed be wrong), still menus 1st popularly surfaced in apps for and by the ripping community, where space saving was the name of the game before DL blanks, and it's simpler/easier to manipulate in an existing layout. Today commercially it seems popular with chapter menus, warning messages, &/or anywhere else the author(s) don't feel the need for eye candy. Slide shows, are also (in my limited) experience something that surfaced after DVDs were out there a while. Holding the cell [as with menu end action in DVDA] is IMHO less useful so less common, but works if you don't want the cell to auto advance to the next one.

"...it's because the file is likely not contiguous with the previous file on the DVD..."

Could be I guess, but don't see huge problems with DVDs that jump around a bit, not following the cell order or even staying within the same title, meaning you'd have separate ac3 files split up by quite a bit of disc.

alk3997 wrote on 1/11/2007, 2:38 PM

Thanks (all) for the help with this. I looked at the rendered video files and sure enough there are only a very few frames of video per song. At least I understand now why the video is so small with the slide show and grows substantially with a rendered video. Thanks again for the help in understanding that.

I'll try to look at how I can force the AC3 tracks to be placed on the disc contiguously.

Andy

ScottW wrote on 1/11/2007, 8:29 PM

Even if you get the tracks to be placed next to each other, you'll still have a pause on many players since the DVD player must determine what to do when it reaches the end of one track.

alk3997 wrote on 1/12/2007, 7:35 PM

Yes - I'm going to run (make) an experiment by changing the AC3 to PCM and see if the break still occurs. I also want to see if it is the picture change that causes the problem.

Andy