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An Introduction
to FLAC & What Exactly is Lossless Compression
One of the best forms of audio compression processes used
today is the FLAC. This is the acronym of Free Lossless Audio
Codec that has an audio format that is like MP3. The only
difference here is that the compression is lossless which
means that there is no loss in quality when audio is
compressed with FLAC. You can get an exact idea of its
application when you look at a zip file when all documents are
compressed into a single zip file.
With FLAC it is possible to get better audio compression as
this is compression that is designed for use in high end audio
systems. It is possible to play your favorite music in FLAC
files in your favorite player, as you would an MP3 file. Most
operating systems support FLAC like Windows, BeOS, Amiga and
‘UNIX’.
Today, FLAC is the fastest form of lossless audio codec that
is widely supported in many programs and FLAC supporting
devices. In addition to this, FLAC has an open-source
reference implementation, follows a well documented format,
and is non-proprietary and other implementations. The main
FLAC project maintains a format while providing programs and
libraries of the working of FLAC files.
The word ‘free’ in FLAC does not only indicate that it is
available free of cost. It also means that its format
specification can be used by anyone in public, for any
purpose. In addition to this, it also means that the FLAC
format and any of its implemented encoding and decoding
methods are covered by a known patent.
By ‘free’, it also means that the source code of FLAC is
available under open-source licenses. In records, this is
truly the first form of open and free lossless audio format
available in the market today.
The most specific features of FLAC is its lossless compression
of audio data. The meaning of this is that there is no loss of
information during the encoding of audio data. On comparing
the decoded audio, you find that it is bit by bit identical to
the data that was fed to the encoder. Each frame of FLAC
encoded data has a 16 bit CRC of the frame data that is used
for detecting errors in transmission.
In addition to this, an MD5 signature of the original
unencoded audio data is stored in the file header to ensure
the integrity of the audio data. This can be compared later
either while decoding or testing. Lots of consumer devices
ranging from home stereo to car stereo equipment and portable
players support FLAC.
The decode speed in FLAC is fast and asymmetric where decoding
is done with integer arithmetic and not as computer intensive
as other perceptual codecs. The metadata system of FLAC is
very flexible where it supports tags, cue sheets, seek tables
and cover art. With FLAC, it is possible to define and
implement new metadata blocks in new versions of FLAC without
having to break decoders or older streams.
As FLAC supports fast sample accurate seeking, FLAC is useful
for playback and in editing applications. With all FLAC frames
having sufficient data for decoding frames, there is no need
of relying on previous or next frames. With the help of
framing, CRCs and sync codes FRAC permits decoders to pick up
in the middle of a stream without delay.
It is possible to convert your data, with no generation loss,
to other formats in the future as FLAC has an open format.
There is also a verify option in FLAC that decodes the encoded
data stream in parallel with the encoding process so that the
original data can be compared to the resultant data. If there
is a mismatch at all, the encoding process is aborted.
In addition to all this, FLAC provides for convenient CD
archiving with its ‘cue sheet’ metadata block that permits the
storage of CD table of contacts and track and index points. So
if the original CD gets damaged, it is possible to export this
cue sheet so that it is possible to burn an exact copy when
needed.
Source:
http://www.flacsite.com |
