Flac lossless compression
When playing in foobar, right-click the song and select the conversion format.
Lossless audio compression format FLAC
Transferred from: C, and the building system on Project Builder.
FLAC project includes the following aspects:
Format of data stream
Reference encoders and decoders provided in the form of libraries.
Flac, a program that can encode and decode FLAC files in command Lame mode. )
Metaflac, the metadata editor of flac file, works in command line mode.
Input plug-ins for different audio players
When we say "FLAC is free", it doesn't just mean you can get it for free. More importantly, the file format of FLAC is completely open to the public, and you can use it for any purpose (FLAC project only reserves the right to maintain FLAC format specifications and confirm compatibility features). The file format and encoding/decoding implementation of FLAC are not restricted by any known patents. In addition, all source code can be obtained under the open source license.
FLAC is the world's first completely open and free lossless audio compression format.
Features of FLAC:
Lossless compression: The encoded audio (PCM) data has no information loss, and the decoded audio is the same as every byte input by the encoder. Each data frame has a 16 CRC check code of the current frame, which is used to monitor data transmission errors. For the whole audio data, the MD5 tag of the original uncompressed audio data is also saved in the file header for checking the data during decoding and testing.
Fast: FLAC values the speed of decoding more. Decoding only needs integer operation, and compared with most coding methods, it requires lower operation speed. Real-time decoding can be easily implemented on very common hardware.
Hardware support: FLAC is the only lossless compression coding supported by hardware, because it provides free decoding examples and has low decoding complexity.
Streamable: each data frame of FLAC contains all the information needed for decoding. Decoding the current frame does not need to refer to the data frames before or after it. FLAC uses synchronization code and CRC (similar to MPEG and other coding formats), so that the decoder has the minimum delay when jumping and positioning in the data stream.
Locatable: FLAC supports fast sampling and accurate positioning. This is not only good for playing, but also makes FLAC files easy to edit.
Flexible metadata: new types of metadata blocks can be defined and implemented without affecting the use of old data streams and decoders. At present, the existing metadata types include tags, clue tables and location tables. Registered applications can define their own metadata types.
Very suitable for archiving applications: FLAC is an open coding format with no data loss. You can convert it into any other format you need. In addition to the CRC and MD5 tags of each data frame to ensure data integrity, flac also provides a verification option. When encoding with this option, the encoded data will be decoded immediately and compared with the original input data. Once the difference is found, FLAC will quit and give an alarm prompt. Well, what's there to worry about when something is compressed like this? )
Easy backup of CD: FLAC has a "cue table" metadata block, which is used to save the content list of CD and the index points of all tracks. You can save a CD into a single file and import it into the cue table of the CD, so that a FLAC file can completely record all the information of the whole CD. When your original CD is damaged, you can use this file to restore an exact copy of the original CD.
Anti-destruction: Due to the frame structure of FLAC, once the data stream is destroyed, the loss will be limited to the destroyed data frame. Usually only a short section is lost. But when many other lossless audio compression formats are destroyed, one destruction will cause the loss of all the data behind.
Features that FLAC does not have:
The data is shrinking. FLAC is specially designed for lossless compression. You can choose many other excellent lossy compression methods, such as Vorbis, MPC and MP3(LAME provides an excellent open source implementation).
SDMI (and so on) compatibility. FLAC is not prepared to support any copy protection methods. In fact, these methods are ultimately a waste of data. (On the other hand, since all these methods have been proved to be ineffective in the end, it can be said that FLAC has compressed these useless data to zero! Of course, we can't prevent some people from using special metablocks for copy protection, but their protection will only be effective on their own decoding products, and other decoders will skip these special metablocks.