flac

 

 


FLAC, APE, ALAC

 

它們都是無損壓縮

APE(Monkey's Audio) # 舊時很多人用

Software: Monkey's Audio Decoder 2.3.1

.ape for audio, and .apl for track metadata

FLAC(Free Lossless Audio Codec)

Software: foobar2000

 * open source

CRC checksums are used for identifying corrupted frames when used in a streaming protocol.

The file also includes a complete MD5 hash of the raw PCM audio in its STREAMINFO metadata header.

FLAC decoding is the fastest among lossless codecs

the decoding process is always quite fast and not dependent on the level of compression.

native FLAC playback support

OS Support

  • Windows 10
  • Android operating system has supported native FLAC playback since version 3.1.
  • macOS High Sierra and iOS 11 add

ALAC(Apple Lossless Audio Codec)

 * open source

Apple Lossless data is frequently stored within an MP4 container(m4a)

 


ReplayGain Scanner

 

FLAC: Values written to Vorbis comment.

APE: Values written to APEv2 tags.

ReplayGain data is stored in tags/comment and can be removed

Track Gain:

increases or decreases the volume of that track to on average 89 dB.

All tracks will be at about the same loudness.

Album Gain:

increases or decreases the volume of the album to be on average 89 dB.

This allows quiet tracks on the album to remain quieter than the loud tracks on the album.

Basically if you listen to an entire album at a time, you should use 'Album Gain'.

If you listen to shuffled/random tracks, you should use 'Track Gain'.

Apply Gain
 

Preferences -> Playback and under ReplayGain select if you want track or album gain and

then use 'apply gain' under Processing.

apply gain and prevent clipping according to peak

 


foobar2000 component

 

DTS decoder

This component decodes .DTS and .DTSWAV files, and also decodes DTS and DTS-derived bitstreams in other raw PCM stream containers,

including .WAV, .FLAC, .WV, and .TAK. It also decodes DTS packets in several stream container formats, including .MP4 and .MKA.

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Monkey's Audio Decoder 2.3.1

Provides decoding support for Monkey's Audio files (.APE) as well as APE Link files (.APL).

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AC3 decoder 0.9.13

This component decodes .AC3 audio files, and streams containing .AC3 format audio in other container formats supported by the player or other components.

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Chacon 3

Chacon is a simple tool for fixing tags by converting them between different character sets.

It can be generally used to fix ID3v1 tags or cue sheets saved in a codepage different from that of your system.

 


bitrate 與 compress ratio

 

bitrate PCM  2304 kbps -壓縮-> FLAC 1595 kbps

為何小了 ?

FLAC is a lossless compression format for PCM audio. # 再次強調

When you compress a WAV file to FLAC it reduces the size by about 1/3. # 通常現象

 => The bitrate for the FLAC file you have is about 1/3 less than the bitrate of the WAV file.

原因:

bitrate is defined. It's "bits of data per second".

So if you compress something, even losslessly, it's at a lower bitrate.

Quality

* "low bitrate" and "low quality" comes from lossy codecs like MP3

* Lossless codecs like FLAC instead let you trade off CPU time (at least during compression) for file size

 


Other