Meridian Lossless Packing, also known as Packed PCM (PPCM),[citation needed] is a lossless compression technique for PCM audio data developed by Meridian Audio, Ltd. MLP is the standard lossless compression method for DVD-Audio content[1] (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,[2] while its use on the discs themselves is at their producers' discretion.
Dolby TrueHD, used in Archival Disc Blu-ray and HD DVD, employs MLP, but compared with DVD-Audio, adds higher bit rates, 32 full-range channels, extensive metadata, and custom speaker placements (as specified by SMPTE).[3]
Standard DVD has a maximum transfer rate of 9.6 Mbit/s, making it impossible to store 6 channels of 24-bit/96 kHz uncompressed audio. MLP is designed to reduce the peak data rate below that rate, as well as reduce average data rate,[4][5] unlike most data compression algorithms that focus only on reducing the average data rates.
In order to be able to quickly start decoding at any point in the audio stream, such as when jumping to a particular time while editing, or restart decoding after transmission errors, MLP puts restart information approximately every 5 ms in the compressed audio stream.[6]