Audio

Audio data specifications

Linear PCM Dolby AC-3 MPEG-2 audio
Sampling frequency 48 or 96 kHz 48 kHz 48 kHz
Number of bits per sample 16/20/24 compressed (16 bits)compressed (16 bits)
Max transfer rate 6.144 Mbit/sec 448 kbits/sec 640 kbits/sec
Max Number of channels 8 5.1 5.1 or 7.1


NTSCPAL
Mandatory Dolby AC-3 and/or Linear PCM MPEG-2 audio and/or Linear PCM
Optional MPEG-2 Audio Dolby AC-3


Philips' provided three practical scenarios for audio.

UseChannelskbits/sec

Case 1: One mono language channel to be mixed with the Center multichannel set.
Multichannel music & effects 5.1 or 7.1 384
Mono English dialogue 1 64
Mono French dialogue 1 64
Mono German dialogue 1 64

Case 2: One of the stereo lingual signals mixed with the L & R channel of the playback multichannel set.
Multichannel music & effects 5.1 or 7.1 384
Mono English dialogue 2 128
Mono French dialogue 2 128
Mono German dialogue 2 128

Case 3: One to be selected for playback.
Multichannel with English dialogue 5.1 or 7.1 384
Multichannel with French dialogue 5.1 or 7.1 384
Multichannel with German dialogue 5.1 or 7.1 384

Audio Signal Decoding System

General

  • up to a maximum of 8 audio streams can be multiplexed into the same cell with a single video stream. Each stream for example is designated for a particular language or special effects & music tracks.
  • Dolby AC-3 used mandatory for 525/60 (NTSC) players and MPEG-2 is mandatory for 625/50 (PAL) players, but optional on discs themselves.
  • LPCM (Linear Pulse Code Modulated) is mandatory for all players, but optional on discs themselves.
  • 48 kHz and 96 kHz uncompressed PCM audio
  • High Definition Audio Experience
  • A 525/60 disc must contain either Dolby AC-3 or LPCM.
  • A 625/50 disc must contain either MPEG-2 audio or LPCM. Due to bandwidth efficiency, most titles will use the more compact Dolby AC-3 or MPEG-2 audio.
  • Extendibility is reserved for new algorithms such as DTS, Sony SDDS, et al.
  • IEC-958 Digital Audio Interface for external decoder/receiver. Output types: compressed AC-3 or MPEG stream, two channel LPCM. DVD players are required only to output a full reconstruction of the Left and Right channels. An external AC-3 decoder would optionally decode all 5.1 channels. A more expensive DVD player would output all 5.1 reconstructed channels.

    Dolby AC-3 parameters

    Sampling frequency 48 kHz
    bitrate 64 kbits/sec to 448 kbits/sec per stream
    Audio coding mode 1/0, 2/0, 3/0, 2/1, 2/2, 3/1, and 3/2 (acmod)
    Characteristics
  • dialog normalization
  • dynamic range compression
  • downmixing (5.1 -> 2 channel) capability
  • Dolby Pro-Logic Encoding (5.1 -> 2 channel)
  • Karaoke mode (voice overlay)

    • MPEG Audio parameters

    Sampling frequency 48 kHz
    MPEG-1: Layer II only
    Mono (32 to 192 kb/s) and Stereo (64 to 384 kb/s)
    MPEG-2
  • main stream (same as MPEG-1)
  • extension stream (up to 528 kbit/sec)
  • sum of main and extension stream up to 912 kb/s
  • unmatrix mode excluded (always MPEG-1 compatible)

    • LPCM Coding

  • Lossless/uncompressed PCM audio
  • Sampling frequency: either 48 kHz or 96 kHz
  • bits/sample: 16, 20, or 24 bits
  • up to 8 PCM channels.

    Due to the user rate bandwidth limitation of 6.144 mbit/sec for any LPCM audio stream, not all combinations of channel count, sample precision and sample rates are permitted. However, up to 8 separate streams are permitted, as long as the combined stream rate is less than or equal to 9.8 mbit/sec. DVD nomenclature states that a single LPCM stream consists of one to 8 channels.

    Sample RateSample Prec.Channel Count
    (Hz)(bits)Mono 2 CH 5 CH 8 CH
    48,00016 Yes Yes Yes Yes
    20 Yes Yes Yes No
    24 Yes Yes Yes No
    96,00016 Yes Yes No No
    20 Yes Yes No No
    24 Yes Yes No No