Wave is the standard form for uncompressed audio on a PC. Since a wave file is uncompressed data - as close a copy to the original analog data as possible - it is therefore much larger than the same file would be in a compressed format such as mp3 or RealAudio. Audio CDs store their audio in, essentially, the wave format. Your audio will need to be in this format in order to be edited using a wave editor, or burned to an audio CD that will play in your home stereo.
WMA is a format similar to MP3. This is essentially a competing format created by Microsoft and used primarily in Windows Media Player and other compatible programs. Microsoft claims that Windows Media files are even better than MP3 files, but MP3 files are still much more prevalent on the internet.
ID3 Tag Name
The ID3 tag is attached to an MP3 audio file to carry information relevant to that MP3. The development of ID3 began in 1996 when it was released that by adding a small chunk of extra data at the start or end of the audio data the MP3 file could hold information about the audio and not just the audio data itself.
File management software and many audio/media players rely on ID3 tag data when working with MP3 files to allow better presentation, sorting and classification of files. Software is available that can edit the information contained in an MP3's ID3 tag, commonly referred to as 'tag editors'. The entire size of the ID3 tag is 128 bytes with a certain amount of bytes allocated to store the song title, artist, album, year, genre and comments.
M3U (.m3u) is the file extension for a playlist of MP3 audio files used by many media players, including Winamp. Like the RAM (.ram) file extension. M3U files only contain the information leading to the actual location (local directory or remote/hyperlink) of the audio file; a .mp3 file.
A M3U file is simply a text file and can be opened in NotePad or a similar text editor allowing you to see the local or remote location of the actual audio file. Example:
Encoders are central to MP3. After all, without an encoder you wouldn't have an MP3. The software in this category allows you to convert files at varying levels of audible quality. MP3 encoders in this section range from simple 'drag and drop' programs to versatile programs offering a variety of options. MP3 Recording software uses real-time MP3 encoders.
MP3 decoding software is commonly used to convert MP3 to WAV format. Often the MP3s are converted into other formats so musicians can sample songs, while some listeners prefer to convert their MP3s to WAV and then CDA to burn them onto a CD. A number of decoders support batch processing of files.
Many digital audio and multimedia players for your computer support playlists. A playlist offers you better organization and management of the various music files on your computer by controlling what files are played and in what order, much like a music playlist used by radio stations. Playlists are commonly used by amateur and professional computer DJs at parties and dances to allow a continuous play of music, queuing programmed and requested songs. Within a playlist file (which can be viewed as a text document) is the local (hard-drive) and/or remote (Internet) location of each file within that playlist. As the audio player moves through each file on the playlist, it sources that file from the specified location, either on your hard-drive or the Internet (a URL).
The sample rate of an audio recording partially determines the overall sound quality. In the recording process, audio samples are saved to memory or disk; the rate each sample of audio input is recorded per second is the sample rate. The sample rate is measured in Hertz (Hz - cycles per second) and Kilohertz (kHz - thousand cycles per second). CD quality audio has a sample rate of 44100Hz, 16-bit (resolution) and stereo (channels). The most common sample rates are 11, 22 and 44kHz, with most recording software supporting sample rates from 6kHz up to 192kHz. Like early footage filmed at a low frame rate looks flickered and robotic, the quality of an audio recording decreases as the sample rate is lowered. For audio recordings destined to be encoded to MP3, 22kHz is considered acceptable.
Bit rate is the amount of information (bits) transferred in a second ('bps' is the abbreviation of bits-per-second). In terms of MP3 audio files, the bit rate unit is more commonly referred to as 'kbps', which is thousand-bits-per-second. The higher the bit rate or 'kbps' of an MP3 file, the higher the sound quality. Most MP3 encoders support a range of bit rates from 24kbps up to 320kbps (or 320,000 bits per second). The most widely used 'standard' bit rate for MP3s is 128kbps, but below that is not especially enjoyable to listen to. At around 160kbps there is a noticeable improvement in the audible quality of an MP3 encoded audio file.
Mode (Channel Mode)
The channel mode determines if the resultant file will be mono or a stereo flavor.
- Mono: One channel.
- Joint Stereo: Toggles between stereo and mono depending on differences and similarities in the left and right channels.
- Dual channels: 2 mono channels. (Encoded independently.)
- Stereo: Normal stereo ( 2 channels)
Constant Bit Rate (CBR) encoding means that you encode a file at a fixed rate, such as 128 Kpbs. For many people this is a common method of encoding MP3s. You can usually tell CBR files because they have consistent file sizes and sound quality.
Variable Bit Rate (VBR) encoding is a method that ensures high audio quality bit-allocation decisions during encoding. The encoder allocates an appropriate amount of data per second, depending on the complexity of the audio file.
If there are very complex parts in a song it will use a quite high bit rate and a lower bit rate for something such as silence. The average bit rate may not be as high as the bit rate of an MP3 of the same quality with constant bit rate.
You should use VBR encoding when consistent audio quality is the top priority.
Variable Bit Rate (VBR) files will encode MP3 files that have a range of bit rates. Why create more data is necessary? The problem with VBR is that some players or MP3 devices may not play them back as well as Constant Bit Rate MP3 files.
Min Bit Rate: the minimum bit rate to use.
Max Bit Rate: The maximum bit rate to use.
Quality Level: Indicates how well the encoder analyzes the audio. The more it analyzes the audio, the better chance it has of getting lower bit rate frames. 0 = highest quality and 9 = lowest quality.
Freedb is a database to look up CD information using the internet. This is done by a client (a freedb aware application) which calculates a (nearly) unique disc ID for a CD in your CD-Rom and then queries the database. As a result, the client displays the artist, CD-title, track list and some additional infmations You can also search for CD-info in the freedb via the web-based search.
Ripping is also referred to as Digital Audio Extraction (DAE). Depending on your operating system (platform) CD ripping software will record the CD audio (.CDA) tracks to WAV format (eg. Windows) or AIFF (eg. Macintosh). It is usually as simple as inserting a CD into the CD-ROM drive of your computer and selecting the tracks to be recorded to hard drive. Ripping can also refer to the recording of vinyl records to digital audio. Several ripping programs now incorporate the option to encode recordings to MP3 and other compressed audio formats.
MP3 is a lossy format. Based on the compression settings chosen by the user, some of the audio data is thrown away or 'lost' to decrease the actual compressed file size. This is why the more an MP3 is compressed (low bit rate and sample rate, mono), the poorer the sound quality. As there are some elements in any sound recording that are inaudible to the human ear, MP3s still manage to sound good even with the loss of data.
MPEG stands for "Moving Pictures Experts Group" and is based on a perceptual coding scheme. There are several versions of the MPEG standard. (MPEG defines the syntax of low bit-rate video and audio bit streams, and the operation of conformant decoders. MP3 is actually an abbreviation for MPEG 1 Layer 3.)
© Gabriel Bouvigne, 1998