MP3 Players

Hardware Media Players

MP3 players are hardware devices to playback compressed sound, and soon possibly video. Initial devices are based on the MP3 codec, but there are other open and closed options, many of which are now considered to be better. See also SoftwareReviews/MediaPlayers for playing back compressed audio on your Linux desktop, and .SoftwareReviews/AudioEditing for software to rip and edit your music.

Types

Hard Disk

These devices use a small hard disk to store the compressed data. They have the advantage that cost per byte is lowest, and capacities are high, but they are prone to skipping, and probably one of the least robust of all the types. Battery life varies, but because they have a moving disk, don't expect them to run for days on a charge. The Apple iPod is the class leader in the larger hard disk category, (5-40Gb) and there is now the smaller hard disk category, where the iPod m ini is very popular (1-5Gb).

Solid State

Solid state systems have no moving parts, relying on RAM to store the data. Cost per byte is much higher than a disk based player, but battery life is good, they are often very compact, usually very skip resistant, and potentially more robust. Capacities have increased as flash RAM capacities have increased, so the range of capacities is from 64MB up to over 1Gb.

Removable Media

Quite a few CD and DVD players can now play back MP3 data stored on CD-R disks. Capacity is fixed to CD-R capacity, but you can switch between disks easily, and blank disks are quite cheap. Sony have also upgraded their MD format recently, increasing capacity, and supporting extra codecs, making MD a more viable option.

Media Servers

Recently devices like the Squeeze Box have arrived, that contain no storage themselves, but connect to a host computer with compressed audio files on them, and then stream the data over a network, outputting an analogue line level signal, s uitable for a domestic audio amplifier.

Codecs

Codecs, are compression and decompression algorithm that take raw sound data, and compress it so it takes up less space. There are several types, and packaging methods.

Lossy

Lossy codecs compress the data by compressing the only the components of the sound that people can actually hear. If done properly an audio file compressed in this manner will take up a great deal less disk space, yet still sound like the uncompressed original. The efficiency and quality of the compressed file depends upon the quality of the algorithm, the implementation and the selected level of compression. MP3 is considered to be first generation, and though popular, is not considered to be as good as later generation codecs. Examples of lossy codes are Ogg Vorbis, MP3 and AAC.

Lossless

Lossless codecs compress all the data, keeping all of it. Lossless codecs can be thought of as Gzipping a file, but using an algorithm and dictionary optimised for sound. A popular Lossless codec is FLAC.

Symmetrical/asymmetrical

For most purposes audio is compressed once and played back many times, so many codecs are highly optimised for playback, so it takes a great deal of time and CPU power to compress the file, but play back is very easy. Symmetrical codecs take the same amount of time to compress as decompress, and are more useful for streaming scenarios where the data needs to be compressed as quickly as possible, and playback happens only once.

Products

Since the launch of the Apple iPod the consumer MP3 market has boomed, and there are now many, many devices available, with options to suit all price ranges. Most are targeted for Wintel users, with scant information on Linux compatibility, even Mac support is infrequently mentioned, but some are quite Linux friendly. Most reviews in the popular press assume Wintel systems using the Windows Media Player format, and Linux/Unix/Mac support is not discussed even if it's available, codec coverage is also often poor, often limited to just MP3/WMA and AAC.

MP3Players (last edited 2008-03-07 16:00:56 by 212)