Wednesday, September 30, 2009

Audio File Basics

Before diving into the software packages, it’s a good idea to first cover some of the basics of the open-source audio world. Unfortunately, the audio world is full of legal and ethical issues that cause problems for the open-source software enthusiast. You’ll need to know what to expect, or you might be disappointed. First, let’s take a quick look at the popular audio file formats used on computers, portable music players, and the Internet.

Common Audio File Formats
.aac Advanced audio coding. An ISO standard audio compression format made popular as the default format for Apple iPod music players

.flac Free lossless audio codec. An open-source, lossless audio format that doesn’t use compression

.ogg Ogg Vorbis. An open-source audio compression format equivalent to MP3 compression and quality

.mp3 MPEG-1 audio layer 3. A patented audio compression format requiring licensing rights

.wav Waveform audio format. A Microsoft and IBM standard for uncompressed audio

.wma Windows media audio. A proprietary audio compression format created by Microsoft and controlled by strict licensing requirements

For each specific audio file format, Ubuntu must use software that can play the audio file. These programs are called codecs. Each codec specializes in a specific audio file format. Ubuntu includes codecs for the FLAC, OGG, and WAV audio file formats by default. There are reasons why it doesn’t contain codecs for the others by default.

By far the most controversial audio file format is MP3. Despite the widespread popularity of the MP3 audio format (or maybe because of it), MP3 has been the subject of numerous legal battles over the past few years based on patent infringement. Because of this legal problem, many Linux distributions shy away from supporting MP3 files by default.

Instead, the Ogg Vorbis audio file format has slowly become the de facto standard for compressed audio files in the open-source audio world. Just about all Linux distributions, including Ubuntu, have full support for .ogg files. Ogg Vorbis is the recommended audio file format for handling most audio files in Linux. Many portable music devices also support the Ogg Vorbis audio file format, allowing you to use the same music files on your Ubuntu workstation and portable music player.

The Linux world also contains a library of reverse-engineered Microsoft audio codecs that can be installed on any Linux platform, including Ubuntu. Be warned, though, because the legality of these libraries is still in question in some countries.

Ubuntu doesn’t include support for Microsoft audio files due to licensing issues. A couple of options are available if you require support for Microsoft audio files on your workstation. You can purchase commercial Linux audio packages that provide support for Microsoft audio file formats. These packages are properly licensed to use the Microsoft audio format.

Source of Information : Wiley Ubuntu Linux Secrets

No comments: