VGM is an audio format

Audio format

An audio format is a medium for storing sound and music. The term is applied to both the physical recording media and the recording formats of the audio content – in computer science it is often limited to the audio file format, but its wider use usually refers to the physical method used to...

 for multiple video game platforms, such as Sega

Sega

, usually styled as SEGA, is a multinational video game software developer and an arcade software and hardware development company headquartered in Ōta, Tokyo, Japan, with various offices around the world...

's Master System

Sega Master System

The is a third-generation video game console that was manufactured and released by Sega in 1985 in Japan , 1986 in North America and 1987 in Europe....

, Game Gear

Sega Game Gear

The was Sega's first handheld game console. It was the third commercially available color handheld console, after the Atari Lynx and the TurboExpress....

, Mega Drive/Genesis, SG-1000 Mark III, MSX

MSX

MSX was the name of a standardized home computer architecture in the 1980s conceived by Kazuhiko Nishi, then Vice-president at Microsoft Japan and Director at ASCII Corporation...

, NeoGeo and many others. It is also used by the ProSonic game engine.

The normal filename extension

Filename extension

A filename extension is a suffix to the name of a computer file applied to indicate the encoding of its contents or usage....

 is .vgm, but files can also be Gzip

Gzip

Gzip is any of several software applications used for file compression and decompression. The term usually refers to the GNU Project's implementation, "gzip" standing for GNU zip. It is based on the DEFLATE algorithm, which is a combination of Lempel-Ziv and Huffman coding...

 compressed into .vgz files.
Technically, .vgz files should be named .vgm.gz, but because some popular operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

s' file manager

File manager

A file manager or file browser is a computer program that provides a user interface to work with file systems. The most common operations performed on files or groups of files are: create, open, edit, view, print, play, rename, move, copy, delete, search/find, and modify file attributes, properties...

s cannot handle file name suffixes that themselves contain a dot, .vgz is used in order to launch a VGM player (eg. Winamp

Winamp

Winamp is a media player for Windows-based PCs and Android devices, written by Nullsoft, now a subsidiary of AOL. It is proprietary freeware/shareware, multi-format, extensible with plug-ins and skins, and is noted for its graphical sound visualization, playlist, and media library features.Winamp...

 with the proper plugin) and not a data compression

Data compression

In computer science and information theory, data compression, source coding or bit-rate reduction is the process of encoding information using fewer bits than the original representation would use....

 program such as WinZip

WinZip

WinZip is a proprietary file archiver and compressor for Microsoft Windows and Mac OS X, developed by WinZip Computing...

 or WinRAR

WinRAR

WinRAR is a shareware file archiver and data compression utility developed by Eugene Roshal, and first released in autumn of 1993. It is one of the few applications that is able to create RAR archives natively, because the encoding method is held to be proprietary.-Developer:The current developer...

.

On November 20, 2005, VGM 1.50 was officially announced, and a new version of the input plugin released. The new version of the format now supports PCM

Pulse-code modulation

Pulse-code modulation is a method used to digitally represent sampled analog signals. It is the standard form for digital audio in computers and various Blu-ray, Compact Disc and DVD formats, as well as other uses such as digital telephone systems...

 optimization

Optimization (computer science)

In computer science, program optimization or software optimization is the process of modifying a software system to make some aspect of it work more efficiently or use fewer resources...

 for the Yamaha YM2612

Yamaha YM2612

thumb|right|Yamaha YM2612The YM2612, aka OPN2, is a six-channel sound chip developed by Yamaha. It belongs to Yamaha's OPN family of FM synthesis chips used in several game and computer systems. Developed as a stripped-down version of the YM2608, it lacks its larger sibling's ADPCM channel,...

 sound chip

Sound chip

A sound chip is an integrated circuit designed to produce sound . It might be doing this through digital, analog or mixed-mode electronics...

, which makes sound files using the chip a lot smaller — sometimes with over 75% of size reduction. The first YM2612 VGM archive, Project 2612, optimized all of its packages soon after.

As of May 6, 2011, the official VGM specification was updated from version 1.50 to 1.60; the following non-exhaustive list details each new change:
Version 1.51 changes (unofficial update)

The 1.51 spec sheet documents that this version is compatible with the 1.50 specification (with exception of the dual-chip support), but Maxim's in_vgm Winamp plugin still exhibits issues when utilized.

• Support for audio playback and manipulation of many new chips and formats, notably:
  • The YM Series (YM2203, YM2608, YM2610, YM3812, YM3526, Y8950, YMF262, YMF271, YMF278B, and YMZ280B)
  • RF5c68 and RF5c164 (Sega CD PCM)
  • Sega PCM and Sega 32x PWM
  • AY-3-8910
• Data block type information has been added for all new chips that need additional data.
• SN76489 Flags have been added.
• Dual-chip support has been added for nearly every chip.

Version 1.60 changes

Several new optimization methods have been created (optvgmrf and optvgm32).

• RF5cxx and PWM stream data blocks and a command for optimizing RF5cxx data streams have been added.
• Ability to control DAC Streams more easily has been added to support better optimizations.

As of the 1.60 update, compatibility with 1.50 format players has been broken.

External links

• VGM File Format Official specifications
• http://www.smspower.org/forums/viewtopic.php?t=11965 Maxim's in_vgm Winamp plugin, and Valley Bell's updates
• Chipamp - Winamp plug-in bundle compiled by OverClocked ReMix
  OverClocked ReMix
  OverClocked ReMix, also known as OC ReMix and OCR, is a non-profit organization dedicated to preserving and paying tribute to video game music through arranging and re-interpreting the songs with new technology and software, as well as by various traditional means...
  
   allowing playback of over 40 chiptune and tracker formats
• Audacious Media Player - Audacious Media Player
  Audacious Media Player
  Audacious is a free software audio player with a focus on low resource usage, high audio quality, and support for a wide range of audio formats. It is designed primarily for use on POSIX-compatible systems such as Linux, with limited support for Microsoft Windows...
  
  is capable of playing VGM files out of the box on Linux/Unix systems. A patch from this webpage is required to enable playback of VGM files that utilize the YM2413 synthesizer, and PSG Master System and Mega Drive/Genesis VGMs are known to work with or without the patch.
• Audio Overload - Another program for playing VGMs. Available on Mac OS X, Windows, and x86/x86-64 Linux.
• Noise Entertainment System - a NSF/e, GBS, VGM and SPC player for the iPhone and iPod touch.