The Unofficial DVD-Audio Specification


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
012Identifier string - "DVDAUDIO-AMG"
124Relative sector pointer to last sector in AMG (i.e. the last sector of AUDIO_TS.BUP)
1612Padding (zero)
284Relative sector pointer to last sector in AMGI (i.e. the last sector of AUDIO_TS.IFO)
322DVD Specifications Version (0x0012)
344Padding (zero)
382Number of Volumes (0x0001)
402Current Volume (0x0001)
421Disc Side (0x01)
434Padding (zero)
471??? (0x01 on a disk without SV, 0x00 on a disk with SV)
484Relative 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
5210Padding (zero)
621Number of video titlesets
631Number of audio titlesets
6432Unknown (zero) - "Provider ID" in VIDEO_TS.IFO
968Unknown (zero) - "VMG Position Code" in VIDEO_TS.IFO
10424Padding (zero)
1284End Byte Address of AMGI_MAT (0x07ff) - i.e. the end byte of this block of data
1324Unknown (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
02Number of titles
22Byte 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
01High nibble: ??? 0x8 for ATS, 0x4 for VTS
Low nibble: Titleset number???
11Number of tracks in title
22Padding (zero)
44Total length of title (in PTS ticks)
81Titleset number
91Title number within titleset
104Relative 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