• Dolby Metadata: Control the Audio Experience

    Dolby metadata gives broadcasters a simple and powerful way to ensure that audiences enjoy a quality, accurate audio experience, whether they're listening in full surround, stereo, or mono.

    Optimal Sound for Your Setup

    There was a time when every television had a single speaker in it, and every program was broadcast in mono. Then came stereo sound and 5.1-channel surround sound. You may have different setups within your home—a TV with two built-in speakers in your bedroom and a full-featured home theater in your living room. Dolby® metadata ensures that you experience optimal sound no matter which playback system you choose.

    Metadata simply means "data about data." In the case of Dolby metadata, it's information about the audio portion of broadcast stream. This information includes three key parameters, sometimes called the three Ds:

    • Dialogue normalization
    • Dynamic range control
    • Downmixing

    Proper setting of the three Ds provides you with the best possible audio experience given your speaker count, the ambient noise levels in your listening environment, and the quality of your playback equipment.

    The Path of Metadata

    Broadcasters set Dolby metadata levels when preparing content for broadcast. This could be at the time the content is created (production) or later during mastering (postproduction). The Dolby metadata travels alongside the content's audio program through the broadcast infrastructure until the audio and metadata are encoded for transmission.

    When the broadcast signal reaches your home, the encoded data must be decoded. This task is accomplished by the decoder built into your television, set-top box, or A/V receiver. Once decoded, the Dolby metadata instructs your system on loudness control, dynamic range, downmixing, and any other parameters set before transmission.

    • The Intended Experience

      Dolby metadata tells your television or A/V receiver how to process the audio part of a program, protecting the audio integrity of your entertainment.

    • Consistent Loudness Levels

      The dialogue normalization (or dialnorm) feature in Dolby metadata helps match loudness levels between programs and between media, so you enjoy a more consistent listening experience.

    • Late-Night Listening

      Dynamic range control lets you reduce the overall volume but still hear the quieter parts of a program. It's perfect when you don't want to disturb the neighbors or others in your home.

    • 5.1 Channels Not Required

      The downmixing feature in Dolby metadata means you can listen to multichannel programming using fewer speakers. Without downmixing, you'd need a 5.1-channel system to enjoy a 5.1-channel broadcast.

    Dolby Metadata for Professionals

    Dolby metadata provides a number of key parameters designed to give consumers the optimal sound for any program regardless of their listening system.

    Broadcasters

    Deliver multichannel surround sound and more compressed stereo sound within a single audio stream using Dolby metadata.

    Parameter

    Cinema Production

    Drama

    Documentary

    Music

    Live Sport

    Dialogue level

    -27

    -23

    -23

    -23

    -23

    Channel mode

    3/2

    3/2

    3/2

    3/2

    3/2

    LFE

    Enable

    Enable

    Enable

    Enable

    Enable

    Bitstream mode

    Film Standard

    Film Light

    Film Light

    Music Light

    Film Light

    RF mode pro

    Film Standard

    Film Light

    Film Light

    Music Light

    Film Light

    RF overmodulation protection

    Disable

    Disable

    Disable

    Disable

    Disable

    Center downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Surround downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Dolby Surround mode

    N/A

    N/A

    N/A

    N/A

    N/A

    Audio production information

    Yes

    Yes

    Yes

    Yes

    Yes

    Mix level

    105 dB

    85 dB

    85 dB

    95 dB

    85 dB

    Room type

    Large

    Small

    Small

    Small

    Small

    Copyright

    Yes

    Yes

    Yes

    Yes

    Yes

    Original bitstream

    Yes

    Yes

    Yes

    Yes

    Yes

    Preferred stereo downmix

    Lt/Rt

    Lo/Ro

    Lo/Ro

    Lo/Ro

    Lo/Ro

    Lt/Rt center downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Lt/Rt surround downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Lo/Ro center downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Lo/Ro surround downmix level

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    0.707 (–3 dB)

    Dolby Surround EX™ mode

    Not Indicated

    Not Indicated

    Not Indicated

    Not Indicated

    Not Surround EX

    A/D converter type

    Standard

    Standard

    Standard

    Standard

    Standard

    DC filter

    Enable

    Enable

    Enable

    Enable

    Enable

    Lowpass filter

    Enable

    Enable

    Enable

    Enable

    Enable

    LFE lowpass filter

    Enable

    Enable

    Enable

    Enable

    Enable

    Surround 3 dB attenuation

    Enable

    Disable

    Disable

    Disable

    Disable

    Surround phase shift

    Enable

    Enable

    Enable

    Disable

    Enable