Meridian Lossless Packing

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Meridian Lossless Packing , MLP, also known as Packed PCM (PPCM) or Dolby Lossless , is a proprietary lossless compression algorithm for digital sound recordings. The format was specially designed with high-resolution audio data and multi-channel applications such as DVD (audio) in mind.

History and future

Meridian Lossless Packing was developed and patented by Meridian Audio and its partners. The license is now being marketed by Dolby Laboratories. The MLP descendant Dolby TrueHD is used in the successor to the DVD , the Blu-ray Disc (also the HD DVD ) .

features

Meridian Lossless Packing offers packing rates between about 1.5 and over 3 to 1 depending on the number of channels, type of content and resolutions, with most of the savings coming from the gain of redundancy between the channels: more channels mean better yield.

It is suitable for audio material with sampling rates from 44,100 Hz to 192,000 Hz, up to 24 bits per sample and up to 64 channels with different resolutions.

In addition, it is easy to implement and the decoding requires relatively little computing power - even in the case of six channels with 96 kHz sampling rate and 24 bit sampling depth; important for hardware support. MLP contains mechanisms for correcting errors up to a duration of 2 ms, offers an additional metadata channel in the data stream and an entry point for the decoder every 30 ms at the latest.

use

DVD-Audio

Working Group 4 of the DVD Forum decided to include the option of using MLP on DVD-Audio in the specification in order to reduce the data rate and thus increase playing times. This ensures that the defined maximum transfer rate of a DVD-A of 9.6 megabits per second is not exceeded even with 6 channels at 24 bit / 96 kHz (uncompressed 13.8 Mb / s) and for the highest quality levels of a DVD Audio (192 kHz / 24 bit stereo, multi-channel audio 96 kHz at 24 bit) at least 74 minutes of playing time per side and shift are possible.

Alternatives

Free and license-free formats such as B. FLAC or WavPack are (still) largely limited to the PC area.

FFmpeg contains a free encoder and decoder for MLP and TrueHD.

literature

  • Thomas Görne: Sound engineering. Fachbuchverlag Leipzig by Carl Hanser Verlag, Munich a. a. 2006, ISBN 3-446-40198-9 .
  • Roland Enders: The home recording manual. The way to optimal recordings. 3rd, revised edition, revised by Andreas Schulz. Carstensen, Munich 2003, ISBN 3-910098-25-8 .

Web links

Commons : Meridian Lossless Packing  - collection of images, videos and audio files