Information AboutFlac |
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FLAC, an acronym for ''' Free Lossless Audio Codec ''', is a popular format for Audio Compression . Unlike Lossy codecs such as Vorbis , MP3 and AAC , it does not remove any information from the audio stream and is suitable both for everyday playback and for archiving audio collections. The FLAC format is currently well supported by many audio software projects. On January 29th , 2003 , Xiphophorus (now called the Xiph.Org Foundation ) announced the incorporation of FLAC into their banner, adding it to Ogg , Vorbis , Theora , Speex , and others.
THE PROJECT The FLAC project consists of:
"Free" means that the specification of the stream format can be implemented by anyone without prior permission (Xiph.org reserves the right to set the FLAC specification and certify compliance), and that neither the FLAC format nor any of the implemented encoding/decoding methods are covered by any patent. It also means that the reference implementation is Free Software and the sources for libFLAC and libFLAC++ are available under Xiph.org's BSD License , and the sources for flac, metaflac, and the plugins are available under the GPL . In its stated goals, the FLAC project encourages its developers not to implement copy prevention features of any kind. {Link without Title} COMPARISONS FLAC is for efficient packing of audio data, unlike general lossless algorithms such as ZIP and Gzip . While ZIP may compress a CD-quality audio file by 10–20%, FLAC achieves compression rates of 30–50%. Lossy codecs can achieve ratios of 80% or more by discarding data from the original stream. FLAC uses Linear Prediction to convert the audio samples to a series of small, uncorrelated numbers (known as the residual), which are stored efficiently using Golomb-Rice Coding . It also uses Run-length Encoding for blocks of identical samples, such as silent passages. The technical strengths of FLAC compared to other lossless codecs lie in its ability to be streamed and in a fast decode time, which is independent of compression level. As with any lossless scheme, FLAC is also a popular archive format for owners of CDs and other media who wish to preserve their valuable audio collections. If the original media is lost, damaged, or worn out, a FLAC copy of the audio tracks ensures that an exact duplicate of the original data can be recovered at any time, an exact restoration impossible from a lossy archive (e.g., MP3) of the same data. A CUE File can optionally be created when Ripping a CD. If a CD is read and ripped perfectly to FLAC files, the CUE file allows later burning of an audio CD that is identical in audio data to the original CD, including track order, silence between tracks, and CD-Text . However, additional data present on some audio CDs such as lyrics and CD+G graphics are beyond the scope of a CUE file and most ripping software so that data will not be archived. The Hydrogenaudio Wiki features a comparison of lossless codecs, including FLAC. TECHNICAL FLAC supports only Fixed-point samples, not Floating-point . This is to eliminate any rounding errors to ensure bit-perfect reproduction. It can handle any PCM Bit Resolution from 4 to 32 Bit s per sample, any Sampling Rate from 1 Hz to 1,048,570 Hz in 1 Hz increments, and any number of channels from 1 to 8. Channels can be grouped in cases like Stereo and 5.1 channel Surround to take advantage of interchannel correlations to increase compression.
SOFTWARE SUPPORT CDDA Burning
Transcoding
Line-in Recording
Playback
Ripping
Tagging HARDWARE SUPPORT
EXTERNAL LINKS
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