In addition to the Simple Audio Manager (SAMG) stored in the AUDIO_PP.IFO file, there is a second audio manager stored on a DVD-Audio disk known as the Audio Manager (AMG). This is the information stored in the AUDIO_TS.IFO file.
In a so-called "Universal" or "Hybrid" disc, the AMG will contain pointers to Video IFO files located in the VIDEO_TS zone on the disk. My understanding is that a DVD-Audio player will use the Audio Manager (AMG - AUDIO_TS.*) to control playback (using both ATS and VTS files), and that a DVD-Video only player will use the Video Manager (VMG - VIDEO_TS.*) to control playback (using only the VTS files).
The AMG consists of the AUDIO_TS.IFO file, optionally followed by an AUDIO_TS.VOB file, followed by the backup AUDIO_TS.BUP file.
The structure and contents of the AUDIO_TS.IFO is very similar to a VIDEO_TS.IFO file and is as follows:
| Offset | Size (bytes) | Description |
|---|---|---|
| 0 | 12 | Identifier string - "DVDAUDIO-AMG" |
| 12 | 4 | Relative sector pointer to last sector in AMG (i.e. the last sector of AUDIO_TS.BUP) |
| 16 | 12 | Padding (zero) |
| 28 | 4 | Relative sector pointer to last sector in AMGI (i.e. the last sector of AUDIO_TS.IFO) |
| 32 | 2 | DVD Specifications Version (0x0012) |
| 34 | 4 | Padding (zero) |
| 38 | 2 | Number of Volumes (0x0001) |
| 40 | 2 | Current Volume (0x0001) |
| 42 | 1 | Disc Side (0x01) |
| 43 | 4 | Padding (zero) |
| 47 | 1 | ??? (0x01 on a disk without SV, 0x00 on a disk with SV) |
| 48 | 4 | Relative sector pointer from end of AUDIO_TS.IFO to start of AUDIO_SV.IFO, zero if there is no AUDIO_SV.IFO on the disk |
| 52 | 10 | Padding (zero) |
| 62 | 1 | Number of video titlesets |
| 63 | 1 | Number of audio titlesets |
| 64 | 32 | Unknown (zero) - "Provider ID" in VIDEO_TS.IFO |
| 96 | 8 | Unknown (zero) - "VMG Position Code" in VIDEO_TS.IFO |
| 104 | 24 | Padding (zero) |
| 128 | 4 | End Byte Address of AMGI_MAT (0x07ff) - i.e. the end byte of this block of data |
| 132 | 4 | Unknown (zero) - "First-Play PGC Start Byte" in VIDEO_TS.IFO |
| TO DO: More data exists if there are still images or an AUDIO_TS.AOB. However, it is all zero if those elements don't exist. | ||
The second and third sectors both contain very similar tables. For disks without a Video Zone, both tables are identical, if there is a linked Video Zone, then the second sector contains pointers to both ATS and VTS titles, but the third sector only contains pointers to ATS titles.
| Offset | Size (bytes) | Description |
|---|---|---|
| 0 | 2 | Number of titles |
| 2 | 2 | Byte pointer to last byte of data in this table (e.g. 0x0057 to indicate the last byte is at 0x0857 in this file) |
| The following table repeats once for each titleset | ||
| 0 | 1 | High nibble: ??? 0x8 for ATS, 0x4 for VTS Low nibble: Titleset number??? |
| 1 | 1 | Number of tracks in title |
| 2 | 2 | Padding (zero) |
| 4 | 4 | Total length of title (in PTS ticks) |
| 8 | 1 | Titleset number |
| 9 | 1 | Title number within titleset |
| 10 | 4 | Relative sector pointer to ATSI (i.e. from start of AUDIO_TS.IFO to start of relevant ATS_XX_0.IFO) |
Information concerning the AUDIO_TS.VOB file (and possibly the still pictures) are in the subsequent sectors. These sectors are not yet documented.
Next: ATS_XX_0.IFO