The Unofficial DVD-Audio Specification


The structure of the AUDIO_PP.IFO integrates information on video linking, although not for all DVD specifications (consistently found with spec 0x0012). Further, this file may be useful in identifying "gapless" tracks, as will be made clearer in Some notes on Hybrids. The main change in this new version is the use of chapters instead of tracks as basic count units.

The structure of the AUDIO_PP.IFO is as follows:

AUDIO_PP.IFO   Version 2.1 Table [Dec 2007, F. Nicol from original work by D. Chapman]
OffsetSize (bytes) Description Values
012Identifier string "DVDAUDIOSAPP"
122Total number of chapters on the disk max 99
142DVD Specifications Version 0x0012 [0x0200, 0x0000]
The following record appears once for each chapter, sorted by Group and then chapter number:
+02Padding (0)
+21Group Number 1...9
+31Chapter Number within Group 1...99
+44Start Presentation Timestamp (PTS) for chapter.This is the PTS in the AOB file.
Video linking titles tested with 0x0249, irrespective of audio characteristics of video titles linked to.
First title in video titlesets were used for tests.
+84Length of chapter in PTS ticks. Video linking titles have a null PTS length.
+124Padding (0)
+164Audio format (samplerate and depth) plus other currently unidentified informationFirst byte:
0xC8 : start of group
Linking groups considered as groups
0x48 : chapter that does not start a group
Single title groups are coded with 0xC8
Second byte:
0F : 16 bits
1F : 20 bits
2F : 24 bits
Third byte:
8F : 44kHz
0F : 48kHz
1F : 96kHz
2F : 192kHz
Fourth byte:
00 : 1 channel
01 : 2 channels
Video linking groups:
last three bytes are null, hence the coding is either
C8 00 00 00 or 48 00 00 00
For each chapter
+404Absolute sector pointer to first sector of AOB for this chapter
+444Absolute sector pointer to first sector of AOB for this chapter
+484Absolute sector pointer to last sector of AOB for this chapter

According to the Sonic DVD White Paper (PDF file) and other sources, a DVD-Audio disk can contain two "content managers". The first is for simple audio-only DVD players (such as portables or in-car units) and according to that white paper, this can store details on up to 314 chapters. This is known as the Simple Audio Manager (SAMG) and contains enough information by itself for full playback of the audio content within the DVD.

The AUDIO_PP.IFO appears to always be exactly 128 kilobytes in size, and contains 8 identical copies of a 16K block of data. This 16K block of data contains a 16 byte header plus one 52 byte record for each chapter on the DVD. This allows a maximum of 314 records in the 16K block - the same number as mentioned in the above white paper - which implies that the AUDIO_PP.IFO file should be referred to as the Simple Audio Manager (SAMG).