Meridian Lossless Packing, also known as Packed PCM (PPCM), is a

lossless compression Lossless compression is a class of data compression that allows the original data to be perfectly reconstructed from the compressed data with no loss of information. Lossless compression is possible because most real-world data exhibits statisti ...

technique for PCM audio data developed by Meridian Audio, Ltd. MLP is the standard lossless compression method for

DVD-Audio DVD-Audio (commonly abbreviated as DVD-A) is a digital format for delivering high-fidelity audio content on a DVD. DVD-Audio uses most of the storage on the disc for high-quality audio and is not intended to be a video delivery format. The ...

content (often advertised with the Advanced Resolution logo) and typically provides about 1.5:1 compression on most music material. All DVD-Audio players are equipped with MLP decoding, while its use on the discs themselves is at their producers' discretion. Dolby TrueHD, used in

Archival Disc Archival Disc (AD) is the trademarked name of a discontinued optical disc Data storage device, storage medium designed by Sony and Panasonic for long-term digital storage. First announced on 10 March 2014 and introduced in the second quar ...

Blu-ray Blu-ray (Blu-ray Disc or BD) is a digital optical disc data storage format designed to supersede the DVD format. It was invented and developed in 2005 and released worldwide on June 20, 2006, capable of storing several hours of high-defin ...

and

HD DVD HD DVD (short for High Density Digital Versatile Disc) is an obsolete high-density optical disc format for storing data and playback of high-definition video.

, employs the MLP codec, but compared with DVD-Audio, adds higher bit rates, 32 full-range channels, extensive metadata, and custom speaker placements (as specified by

SMPTE The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded by Charles Francis Jenkins in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and e ...

). Dolby Laboratories
"Dolby TrueHD (MLP) high-level bitstream description"
2018 p. 6. Standard DVD has a maximum transfer rate of 9.6 Mbit/s, around 70 percent of the bit rate needed to store 6 ''uncompressed'' audio channels of 24-bit/96 kHz. Should MLP not be able to compress the stream below the maximum transfer rate – or in case there is a need to reduce the size to fit overall disc capacity – it can exploit (lossy) pre-quantification zeroing out least significant bits when necessary. The MLP stream can also contain "substreams", like surround and stereo downmix, which need not be of the same bit depth or sampling frequency – this further enables (lossy) pre-processing to save space. TrueHD streams cannot do this (likely because Blu-Ray discs have higher storage capacity). MLP is ''streamable'': A decoder can pick up the stream and start decoding from that point on nearly instantly, where the encoder has inserted a "restart block" in the stream. Typically, restart information is inserted approximately every 5 ms in the audio, Robert C. Maher
"Lossless Compression of Audio Data"
p. 266. about the same as a typical 96 kHz FLAC stream.

MLP in packaged media formats

References

{{Compression formats Lossless audio codecs DVD

MLP in packaged media formats

See also

References