VCD & CD-DA Audio tracks on the same CD (AVCD)

[PigOnWing]

Hello to the forum,

I'm trying to see if it's possible, both in- and out-of-specs, to make some 'bonus VCD tracks' on a CD-Audio.

I understand that such a thing is, indeed, commercially available, as noted in this thread, however I'm not sure if on the album discussed the video tracks appear before or after the CD-DA tracks.

As vitalis noted, I understand that it's indeed within VCD spec to add CD-DA tracks after any MPEG tracks, a function supported both by Philips VideoCD Toolkit, officially, or with manually altering the CUE sheet, as an unofficial method (knowing how the CUE structure works, I assume it should work with Fireburner just as well as with any other CUE-reading burning software).

However I wonder if the opposite is possible just as well - placing the MPEG tracks after the CD-DA tracks, so that if you need to skip the first few tracks - to play in an Audio-CD player - you skip only the first (ISO) data track.

Moreover, I consider the use of the CD-EXTRA format, as opposed to the Mixed-Mode CD; I understand that the 'normal' VCD spec are using mixed-mode, meaning that all data is written in one session, with the first track being a DATA track - where the 'CD-EXTRA' approach is having two sessions - first one containing only CD-DA audio tracks - a CD audio player always sees only the first session - and the second session contains the data - CD-ROM drives always read the last sessions first.

Where does VCD/DVD players fit into this bill? Do they read multisession discs, as a standard? Is the MPEG track needs to be on the first session always, or can it be on the second? Does anyone knows how may I create 'multisession disc' using a CUE-sheet, which is normally aimed at DAO burning? Can I burn DAO, but define, within the image, two 'sessions'?

Many, many thanks for any light shed on any fo these matters.

-- Piggie

[vitualis]

No VCD authoring software I know of will place CD-DA tracks before the video tracks. Speculatively, as long as all the sector addresses in the PBC point correctly to the video tracks, it mayp possible to make a VCD with CD-DA tracks before the video tracks, and have it work on some/most players. I would imagine that PBC interpretation would be essential, however.

Multisession VCDs I would imagine be impossible to make (and have it work). As you've noted, for CD-DA players (i.e., ordinary audio CD players) to play back the audio, it must be on the first session (and generally, they ignore everything else). This is somewhat similar with VCDs. The PBC data as read on the disc isn't so much interpreting the logical filestructure as to looking at predefined sectors for specific information. I would assume that this necessitates that the PBC (i.e., data track 1) and subsequent video tracks will also have to be on the first session.

I don't believe that the CUE/BIN format actually supports multisession discs. Similarly, I don't believe that you can burn multisession discs (e.g., CD-Extra) in "DAO" mode. You can in SAO mode which is kind of similar.

Regards.

[PigOnWing]

Some things never change. Seems I can always count on vitalis to give a prompt response, aided with a vast amount of information, which I have no idea how he can keep it all up.

...yet aother things that never change, is that I'm a nitpicker. :P

[...] Speculatively, as long as all the sector addresses in the PBC point correctly to the video tracks, it mayp possible to make a VCD with CD-DA tracks before the video tracks[...]

I imagined that may be possible - but the two critical issues I have no idea where to begin with are:

1. Where, in the PBC structure, do I point to the tracks? Using VCDEasy, do I manually edit the XML file?
2. After solving that one out, how do I get around to re-ordering the actual tracks? That is, where do teh MPG track begins and where does it end?

[...]Multisession VCDs I would imagine be impossible to make [...] for CD-DA players (i.e., ordinary audio CD players) to play back the audio, it must be on the first session (and generally, they ignore everything else). This is somewhat similar with VCDs. The PBC data as read on the disc isn't so much interpreting the logical filestructure as to looking at predefined sectors for specific information. I would assume that this necessitates that the PBC (i.e., data track 1) and subsequent video tracks will also have to be on the first session. (My Italics - Piggie)

Here I'm less sure about it. [Audio] Tracks can be written to other sessions than the first one - this just usually isn't in practice, as [most/all?] Audio players won't see them. If you will burn such a CD-R - with several Audio Tracks burned in several sessions - it should be quite playable in, say, a CD-ROM drive.

So while it is true the VCD ISO system actually does not contain the MPEG track itself (the .DAT file is actually a pointer to the raw data found on the relevant track), there's no real reason for it to point to a track on a session other than the first. A track is a track is a track is a track - if the session iteslf is recognized.

Hence the issue is, I think, do VCD/DVD players work similar to CD-ROM drives - that is, both read multisession discs, and read the last session first (to get the PBC data needed from the ISO structure).

Well, the issue is, probably, whether all the 'how do I' mentioned above, are possible at all. Manipulating the different tracks, mainly.

I don't believe that the CUE/BIN format actually supports multisession discs. Similarly, I don't believe that you can burn multisession discs (e.g., CD-Extra) in "DAO" mode. You can in SAO mode which is kind of similar.

Ah! That's a term I didn't met before. I assume "SAO" is 'Session at once' - but which software supports it? Fireburner?

Many, many thanks again -

-- Piggie

[vitualis]

I imagined that may be possible - but the two critical issues I have no idea where to begin with are:

1. Where, in the PBC structure, do I point to the tracks? Using VCDEasy, do I manually edit the XML file?
2. After solving that one out, how do I get around to re-ordering the actual tracks? That is, where do teh MPG track begins and where does it end?

VCDImager/VCDXBUILD automatically puts the relevant information in the PBC from the information in the XML file as well as the referenced source files. E.g., if video track 1 is so long, then video track 2 begins at such and such sector.

As for re-ordering the actual tracks, I don't see any real way of doing bar editing the source code and recompiling VCDImager so that it can allow for this.

Here I'm less sure about it. [Audio] Tracks can be written to other sessions than the first one - this just usually isn't in practice, as [most/all?] Audio players won't see them. If you will burn such a CD-R - with several Audio Tracks burned in several sessions - it should be quite playable in, say, a CD-ROM drive.

So while it is true the VCD ISO system actually does not contain the MPEG track itself (the .DAT file is actually a pointer to the raw data found on the relevant track), there's no real reason for it to point to a track on a session other than the first. A track is a track is a track is a track - if the session iteslf is recognized.

Good point. However, I am unsure of the accuracy of determing the sector addresses of things burnt in later sessions "a priori" as I think it may actually depend on the individual drive. I am unsure about this.

Hence the issue is, I think, do VCD/DVD players work similar to CD-ROM drives - that is, both read multisession discs, and read the last session first (to get the PBC data needed from the ISO structure).

I think it is a definitely "maybe". High end stand-alone VCD players (e.g., by Sony) most probably have a specially designed CD drive mechanism. A CD drive designed to play VCDs does not need to read anything but the first session (and indeed, reading the last session first could cause problems for multisession CD-DA discs). Cheaper VCD players, however, may use standard (cheap) IDE CD-ROM drives.

Ah! That's a term I didn't met before. I assume "SAO" is 'Session at once' - but which software supports it? Fireburner?

Session-at-once burning has only been out on the newer drives (don't ask me how new -- but my 2x burner definitely didn't have it). I believe that most newer burning programs support SAO burning. Basically, it is similar to DAO in that each session is burnt without turning off the laser between tracks, but the disc need not be finalised (?? originally designed so that CD-Extra type discs could still have "continous" audio tracks).

Regards.

[PigOnWing]

Lightning fast. I'm still amazed.

As it seems that pretty much all of the issues regarding changin actual tracks / using multisessions / recognition of multisession by different player / and so on, may all be categorized under the definition of 'maybe', I guess the proper interpretation of 'maybe' is 'if you don't want incompatibility issues, don't play with it'.

Especially taking into consideration your point about CD-Extra.

So I'll try to leave most of it as that.


Now my next logical question will be... Can the PBC point to CD-DA tracks? So far, if the tracks are just 'appended' at the end of the MPEG tracks, then they are actually out-of-PBC reach, and actually not really a part of the VCD. They can 'be there', as an Audio-CD just goes to 'Tracks' and plays whatever's there, but can they be incorporated into the VCD structure as well? Say, a menu which will point to CD-DA tracks? Or defining their order via PBC?

Moreover, I have heard rumors that there are some mixed-mode CDs which 'point' the player to skip the first track (if he recognizes the 'pointer', that is). Personally, I think these rumors are false - if the player recognizes it, it simply recognizes a data track and skips it - but if I'm wrong, can it be done for the MPEG tracks as well? Or are they, as far as a CD-DA player goes, 'Data tracks'? If I'm not mistaken, they are written in Raw mode - hence should be identical in structure to CD-DA tracks. Or am I wrong here?

(Actually, I'm afraid I'm getting beyond the scope of this forum. I may just be a bit high from getting answers... )

-- Piggie

[vitualis]

Lightning fast. I'm still amazed.

I think you've just caught me on the computer! I haven't been on the forum very often recently...

Now my next logical question will be... Can the PBC point to CD-DA tracks? So far, if the tracks are just 'appended' at the end of the MPEG tracks, then they are actually out-of-PBC reach, and actually not really a part of the VCD. They can 'be there', as an Audio-CD just goes to 'Tracks' and plays whatever's there, but can they be incorporated into the VCD structure as well? Say, a menu which will point to CD-DA tracks? Or defining their order via PBC?

I'm not 100% sure on this, but I believe that the answer is no. They are essentially just "appended" to the back of a VCD (as far as PBC interpretation anyway). I haven't played around with VCD Toolkit (which can make proper CD-DA tracks in VCDs) but I think that there may be pointers (e.g., like the dat files are pointers) under the CDDA folder that point to any audio tracks in the filesystem (e.g., similar to some Playstation CDs).

Moreover, I have heard rumors that there are some mixed-mode CDs which 'point' the player to skip the first track (if he recognizes the 'pointer', that is). Personally, I think these rumors are false - if the player recognizes it, it simply recognizes a data track and skips it - but if I'm wrong, can it be done for the MPEG tracks as well? Or are they, as far as a CD-DA player goes, 'Data tracks'? If I'm not mistaken, they are written in Raw mode - hence should be identical in structure to CD-DA tracks. Or am I wrong here?

I've never heard of this rumour, but I always thought that those players simply recognised that a track was data rather than audio and automatically skipped it (rather than there being a "pointer").

Regards.

[Big_Jit]

Lemme just ask this because I've asked it before in another thread that was never responded to and I wanna get a straight answer.

Does putting the CD-DA audio on a VCD make the Audio playable in a (or atleast some) regular CD Player or DVD player?

[PigOnWing]

You don't have to justify yourself, vitalis. I'm enjoying the results.

[...]I always thought that those players simply recognised that a track was data rather than audio and automatically skipped it (rather than there being a "pointer").

Yup, that's what I thought as well. The question remains, how will an MPEG track be recognized - data, garbage, or CD-DA which will play as garbage.

I guess it's time for trial-and-error. I tend to over-discuss stuff before I actually try it, when I might get some practical answer by simply burn a bloody sample (and report, of course.).

Does putting the CD-DA audio on a VCD make the Audio playable in a (or atleast some) regular CD Player or DVD player?

The straight answer is "Yes". The easiest method would be to append the tracks by editing the CUE sheet as described here. The result will probably be a CD, that when popped into an audio player, you will have to manuall skip the first few tracks.

What I'm trying to find out in this thread, is if it's possible to alter the Track order, so that you'll have to skip just the first track - which is always a data track, and which some players will skip automatically; or use other methods (like multisession).

But simply appending CD-DA tracks at the end of a VCD, which you can go to directly using 'next' or by number-buttons, is within VCD spec.

(Why do I always have to didactively elaborate? Why can't I just stop at 'Yes'?)

-- Piggie