MP4 player

The Archos Jukebox Recorder 2, a portable media player

The name MP4 player is a marketing term for inexpensive portable media players, usually from little known or generic device manufacturers.[1] The name itself is a misnomer, since most MP4 players through 2007 were incompatible with the MPEG-4 Part 14 or the .mp4 container format. Instead, the term refers to their ability to play more file types than just MP3. In this sense, in some markets like Brazil, any new function added to a given media player is followed by an increase in the number, for example an MP5 or MP12 Player,[2] despite there being no corresponding MPEG-5 standard (as of 2015, the current standard, still being developed, is MPEG-4).

The Archos Jukebox Multimedia was the first commercial portable media player, and was the first to be coined as an MP4 player is a mp4 video.[3][4]

General features

Today's MP4 Players can play video in a multitude of video formats without the need to pre-convert them or downsize them prior to playing them. Some MP4 Players possess USB ports in order for the users to connect it to a PC. Some models also have memory cards to expand the memory of the player instead of storing files in the built-in memory.

Technical information

Chipsets and file formats that are particular to this kind of portable media player.

Anyka

Anyka is a chip that's used by many MP4 Players. It supports the same formats as Rockchip.

Rockchip

Fuzhou Rockchip Electronics's video processing Rockchip has been incorporated into many MP4 players, supporting AVI with no B frames in MPEG-4 Part 2 (not Part 14), while MP2 audio compression is used.[5] The clip must be padded out, if necessary, to fit the resolution of the display. Any slight deviation from the supported format results in a Format Not Supported error message.

Other chipsets

Some players, like the Onda VX979+, have started to use chipsets from Ingenic, which are capable of supporting RealNetworks's video formats.[6] Also, players with SigmaTel-based technology are compatible with SMV (SigmaTel Video).

AMV

An MP4 player from Newsmy, a major PMP manufacturer in China
Main article: AMV video format

The image compression algorithm of this format[7] is inefficient by modern standards (about 4 pixels per byte, compared with over 10 pixels per byte for MPEG-2 / DVD video). There are a fixed range of resolutions (96 × 96 to 208 × 176 pixels) and framerates (12 or 16 frames) available. A 30-minute video would have a filesize of approximately 100 MB at a 160 × 120 resolution.[8]

MTV

The MTV video format (no relation to the cable network) consists of a 512-byte file header that operates by displaying a series of raw image frames during MP3 playback.[8] During this process, audio frames are passed to the chipset's decoder, while the memory pointer of the display's hardware is adjusted to the next image within the video stream. This method does not require additional hardware for decoding, though it will lead to a higher amount of memory consumption. For that reason, the storage capacity of an MP4 player that uses MTV files is effectively less than that of a player that decompresses files on the fly.

See also

Notes

  1. ↑ "MP3≠MP4！区别和认识MP3与MP4的不同！". Beareyes.
  2. ↑ http://lista.mercadolivre.com.br/mp12 retrieved Nov. 22 2009.
  3. ↑ ""MP4教父" 爱可视全球总裁访华力拓中国市场". NetEase.
  4. ↑ "爱可视VS苹果：从MP3到MP4". 致信网.
  5. ↑ "Leading Chinese MP4 IC Design Houses' R&D and Product Strategies Research Report # MIC1324". Electronics.ca Publications.
  6. ↑ "Teclast announces the M series". haomp. 2007-11-28. Retrieved 2008-03-18.
  7. ↑ Israelsen, Paul D. (1993-09-21). "United States Patent 5247357". Retrieved 2007-12-07.
  8. 1 2 voroshil (2007-10-15). "AmvDocumentation". Google Code. Retrieved 2008-04-06.

External links

This article is issued from Wikipedia - version of the Tuesday, February 09, 2016. The text is available under the Creative Commons Attribution/Share Alike but additional terms may apply for the media files.