flac
Free Lossless Audio Codec
see also :
metaflac
Synopsis
flac
[OPTIONS] [infile.wav | infile.aiff |
infile.raw | infile.flac | infile.oga |
infile.ogg | - ] ...
flac
[-d | --decode | -t |
--test | -a | --analyze ]
[OPTIONS] [infile.flac | infile.oga |
infile.ogg | - ] ...
add an example, a script, a trick and tips
examples
source
for i in `ls
*.flac`
do
flac --decode $i
done
source
while read
flac
do
mpeg=$(dirname "$flac")/$(basename "$flac"
.flac).mp3
flac -d -c "$flac" |
lame --cbr -b 192 - "$mpeg"
source
Join many MP3, OGG, and FLAC files into one WAV or FLAC
You can do this with ffmpeg and sox:
for i in *.mp3 *.ogg *.flac
do
ffmpeg -i "$i" "$i.wav"
done
sox *.wav combined.wav
source
How to compare two lossless audio files?
I'd try converting them both to WAV and comparing their
checksums.
ffmpeg -i file1.m4a file1.wav
ffmpeg -i file2.flac file2.wav
md5sum file1.wav
md5sum file2.wav
rm file?.wav
Compare the md5s produced. If they match, congratulations! Your
files contain the same data. If they don't match, post the output
of those commands here, and I'll look. Potentially there is a
bitrate difference or something (there ought not to be... but
there may be, I don't know.)
Note that the ffmpegs will generate comparatively
large intermediate files.
source
ZFS & Deduplicating FLAC Data
I don't know about ZFS, but the FLAC codec has a lot of different
parameters, and the structure inside a FLAC file is not
byte-aligned in general. So any slight change in settings is
likely to give a very different bytestream. Do you know if the
"identical" files were flacced with the same software, the same
software version, and the same settings, on the same
architecture?
Assuming that there are some differences in the bytestream (which
would explain your 1.0 result), a way to test this would be to
decompress and recompress all the FLAC files on the same machine.
(Of course this operation doesn't drop any data, as long as
metadata is kept.)
source
Changing the Album on FLAC files from the command line in Linux
source
How to split big flac file int tracks and fill the id3 tag?
Install reaquired packages on Debian (Ubuntu):
sudo apt-get install cuetools shntool flac
Split flac file and fill id3 tags:
cuebreakpoints sample.cue | shnsplit -o flac sample.flac
cuetag sample.cue split-track*.flac
Some systems has cuetag.sh instead of
cuetag.
source
Extracting metadata from flac header in linux
EasyTAG can do all sorts of renaming based on
metadata.
source
Ripping to FLAC as close to original CD quality as possible (Rubyripper)
The compression level affects how much the song is compressed,
but doesn't affect the quality of the sound:
The compressed files are always perfect "lossless"
representations of the original data.Wikipedia
Higher compression levels save space, but take more processing
power to encode. No matter what level you use, you will have a
perfect replica of the CD quality. Album art isn't typically
included in the sound file, but instead as an image file stored
alongside the music.
description
flac is
a command-line tool for encoding, decoding, testing and
analyzing FLAC streams.
options
A summary of
options is included below. For a complete description, see
the HTML documentation.
General
Options
-v, --version
Show the flac version
number
Show basic usage and a list of
all options
Show detailed explanation of
usage and all options
Decode (the default behavior is
to encode)
Test a flac encoded file (same
as -d except no decoded file is written)
Analyze a FLAC encoded file
(same as -d except an analysis file is written)
Write output to stdout
Silent mode (do not write
runtime encode/decode statistics to stderr)
Do not print anything of any
kind, including warnings or errors. The exit code will be
the only way to determine successful completion.
Do not convert tags from local
charset to UTF-8. This is useful for scripts, and setting
tags in situations where the locale is wrong. This option
must appear before any tag options!
Treat all warnings as errors
(which cause flac to terminate with a non-zero exit
code).
Force overwriting of output
files. By default, flac warns that the output file already
exists and continues to the next file.
-o filename,
--output-name=filename
Force the output file name
(usually flac just changes the extension). May only be used
when encoding a single file. May not be used in conjunction
with --output-prefix.
--output-prefix=string
Prefix each output file name
with the given string. This can be useful for encoding or
decoding files to a different directory. Make sure if your
string is a path name that it ends with a trailing
’/’ (slash).
Automatically delete the input
file after a successful encode or decode. If there was an
error (including a verify error) the input file is left
intact.
If encoding, save WAVE or AIFF
non-audio chunks in FLAC metadata. If decoding, restore any
saved non-audio chunks from FLAC metadata when writing the
decoded file. Foreign metadata cannot be transcoded, e.g.
WAVE chunks saved in a FLAC file cannot be restored when
decoding to AIFF. Input and output must be regular files
(not stdin or stdout).
--skip={#|mm:ss.ss}
Skip over the first number of
samples of the input. This works for both encoding and
decoding, but not testing. The alternative form mm:ss.ss can
be used to specify minutes, seconds, and fractions of a
second.
--until={#|[+|-]mm:ss.ss}
Stop at the given sample number
for each input file. This works for both encoding and
decoding, but not testing. The given sample number is not
included in the decoded output. The alternative form
mm:ss.ss can be used to specify minutes, seconds, and
fractions of a second. If a ’+’ (plus) sign is
at the beginning, the --until point is relative
to the --skip point. If a ’-’
(minus) sign is at the beginning, the --until
point is relative to end of the audio.
--ogg
When encoding, generate Ogg FLAC output instead of
native FLAC. Ogg FLAC streams are FLAC streams wrapped in an
Ogg transport layer. The resulting file should have an
’.oga’ extension and will still be decodable by
flac.
When decoding, force the input to be treated as Ogg
FLAC. This is useful when piping input from stdin or when
the filename does not end in ’.oga’ or
’.ogg’.
--serial-number=#
When used with
--ogg, specifies the serial number to use for
the first Ogg FLAC stream, which is then incremented for
each additional stream. When encoding and no serial number
is given, flac uses a random number for the first stream,
then increments it for each additional stream. When decoding
and no number is given, flac uses the serial number of the
first page.
Analysis
Options
--residual-text
Includes the residual signal in
the analysis file. This will make the file very big, much
larger than even the decoded file.
--residual-gnuplot
Generates a gnuplot file for
every subframe; each file will contain the residual
distribution of the subframe. This will create a lot of
files.
Decoding
Options
--cue=[#.#][-[#.#]]
Set the beginning and ending
cuepoints to decode. The optional first #.# is the track and
index point at which decoding will start; the default is the
beginning of the stream. The optional second #.# is the
track and index point at which decoding will end; the
default is the end of the stream. If the cuepoint does not
exist, the closest one before it (for the start point) or
after it (for the end point) will be used. If those
don’t exist, the start of the stream (for the start
point) or end of the stream (for the end point) will be
used. The cuepoints are merely translated into sample
numbers then used as --skip and
--until. A CD track can always be cued by, for
example, --cue=9.1-10.1 for track 9, even if the
CD has no 10th track.
-F,
--decode-through-errors
By default flac stops decoding
with an error and removes the partially decoded file if it
encounters a bitstream error. With -F, errors are
still printed but flac will continue decoding to completion.
Note that errors may cause the decoded audio to be missing
some samples or have silent sections.
Encoding
Options
-V, --verify
Verify a correct encoding by
decoding the output in parallel and comparing to the
original
--lax
Allow encoder to generate non-Subset files. The
resulting FLAC file may not be streamable or might have
trouble being played in all players (especially hardware
devices), so you should only use this option in combination
with custom encoding options meant for archival.
--replay-gain
Calculate ReplayGain values and
store them as FLAC tags, similar to vorbisgain. Title
gains/peaks will be computed for each input file, and an
album gain/peak will be computed for all files. All input
files must have the same resolution, sample rate, and number
of channels. Only mono and stereo files are allowed, and the
sample rate must be one of 8, 11.025, 12, 16, 22.05, 24, 32,
44.1, or 48 kHz. Also note that this option may leave a few
extra bytes in a PADDING block as the exact size of the tags
is not known until all files are processed. Note that this
option cannot be used when encoding to standard output
(stdout).
--cuesheet=filename
Import the given cuesheet file
and store it in a CUESHEET metadata block. This option may
only be used when encoding a single file. A seekpoint will
be added for each index point in the cuesheet to the
SEEKTABLE unless --no-cued-seekpoints is
specified.
--picture={FILENAME|SPECIFICATION}
Import a picture and store it
in a PICTURE metadata block. More than one
--picture command can be specified. Either a
filename for the picture file or a more complete
specification form can be used. The SPECIFICATION is a
string whose parts are separated by | (pipe) characters.
Some parts may be left empty to invoke default values.
FILENAME is just shorthand for "||||FILENAME". The
format of SPECIFICATION is
[TYPE]|[MIME-TYPE]|[DESCRIPTION]|[WIDTHxHEIGHTxDEPTH[/COLORS]]|FILE
TYPE is optional; it is a number from one of:
0: Other
1: 32x32 pixels ’file icon’ (PNG only)
2: Other file icon
3: Cover (front)
4: Cover (back)
5: Leaflet page
6: Media (e.g. label side of CD)
7: Lead artist/lead performer/soloist
8: Artist/performer
9: Conductor
10: Band/Orchestra
11: Composer
12: Lyricist/text writer
13: Recording Location
14: During recording
15: During performance
16: Movie/video screen capture
17: A bright coloured fish
18: Illustration
19: Band/artist logotype
20: Publisher/Studio logotype
The default is 3 (front cover). There may only be one
picture each of type 1 and 2 in a file.
MIME-TYPE is optional; if left blank, it will be
detected from the file. For best compatibility with players,
use pictures with MIME type image/jpeg or image/png. The
MIME type can also be --> to mean that FILE
is actually a URL to an image, though this use is
discouraged.
DESCRIPTION is optional; the default is an empty
string.
The next part specfies the resolution and color
information. If the MIME-TYPE is image/jpeg, image/png, or
image/gif, you can usually leave this empty and they can be
detected from the file. Otherwise, you must specify the
width in pixels, height in pixels, and color depth in
bits-per-pixel. If the image has indexed colors you should
also specify the number of colors used. When manually
specified, it is not checked against the file for
accuracy.
FILE is the path to the picture file to be imported, or
the URL if MIME type is -->
For example, "|image/jpeg|||../cover.jpg" will
embed the JPEG file at ../cover.jpg, defaulting to type 3
(front cover) and an empty description. The resolution and
color info will be retrieved from the file itself.
The specification
"4|-->|CD|320x300x24/173|http://blah.blah/backcover.tiff"
will embed the given URL, with type 4 (back cover),
description "CD", and a manually specified
resolution of 320x300, 24 bits-per-pixel, and 173 colors.
The file at the URL will not be fetched; the URL itself is
stored in the PICTURE metadata block.
--sector-align
Align encoding of multiple CD
format files on sector boundaries. See the HTML
documentation for more information.
-S
{#|X|#x|#s},
--seekpoint={#|X|#x|#s}
Include a point or points in a
SEEKTABLE. Using #, a seek point at that sample number is
added. Using X, a placeholder point is added at the end of a
the table. Using #x, # evenly spaced seek points will be
added, the first being at sample 0. Using #s, a seekpoint
will be added every # seconds (# does not have to be a whole
number; it can be, for example, 9.5, meaning a seekpoint
every 9.5 seconds). You may use many -S options; the
resulting SEEKTABLE will be the unique-ified union of all
such values. With no -S options, flac defaults to
’-S 10s’. Use --no-seektable
for no SEEKTABLE. Note: ’-S #x’ and
’-S #s’ will not work if the encoder
can’t determine the input size before starting. Note:
if you use ’-S #’ and # is >= samples
in the input, there will be either no seek point entered (if
the input size is determinable before encoding starts) or a
placeholder point (if input size is not determinable).
-P #,
--padding=#
Tell the encoder to write a
PADDING metadata block of the given length (in bytes) after
the STREAMINFO block. This is useful if you plan to tag the
file later with an APPLICATION block; instead of having to
rewrite the entire file later just to insert your block, you
can write directly over the PADDING block. Note that the
total length of the PADDING block will be 4 bytes longer
than the length given because of the 4 metadata block header
bytes. You can force no PADDING block at all to be written
with --no-padding. The encoder writes a PADDING
block of 8192 bytes by default (or 65536 bytes if the input
audio stream is more that 20 minutes long).
-T FIELD=VALUE,
--tag=FIELD=VALUE
Add a FLAC tag. The comment
must adhere to the Vorbis comment spec; i.e. the FIELD must
contain only legal characters, terminated by an
’equals’ sign. Make sure to quote the comment if
necessary. This option may appear more than once to add
several comments. NOTE: all tags will be added to all
encoded files.
--tag-from-file=FIELD=FILENAME
Like --tag, except
FILENAME is a file whose contents will be read verbatim to
set the tag value. The contents will be converted to UTF-8
from the local charset. This can be used to store a cuesheet
in a tag (e.g.
--tag-from-file="CUESHEET=image.cue").
Do not try to store binary data in tag fields! Use
APPLICATION blocks for that.
-b #,
--blocksize=#
Specify the block size in
samples. Subset streams must use one of 192, 576, 1152,
2304, 4608, 256, 512, 1024, 2048, 4096 (and 8192 or 16384 if
the sample rate is >48kHz).
-m,
--mid-side
Try mid-side coding for each
frame (stereo input only)
-M,
--adaptive-mid-side
Adaptive mid-side coding for
all frames (stereo input only)
-0..-8,
--compression-level-0..--compression-level-8
Fastest compression..highest
compression (default is -5). These are synonyms for
other options:
-0, --compression-level-0
Synonymous with -l 0
-b 1152 -r 3
-1,
--compression-level-1
Synonymous with -l 0
-b 1152 -M -r 3
-2,
--compression-level-2
Synonymous with -l 0
-b 1152 -m -r 3
-3,
--compression-level-3
Synonymous with -l 6
-b 4096 -r 4
-4,
--compression-level-4
Synonymous with -l 8
-b 4096 -M -r 4
-5,
--compression-level-5
Synonymous with -l 8
-b 4096 -m -r 5
-6,
--compression-level-6
Synonymous with -l 8
-b 4096 -m -r 6
-7,
--compression-level-7
Synonymous with -l 8
-b 4096 -m -e -r 6
-8,
--compression-level-8
Synonymous with -l 12
-b 4096 -m -e -r 6
--fast
Fastest compression. Currently synonymous with
-0.
--best
Highest compression. Currently synonymous with
-8.
-e,
--exhaustive-model-search
Do exhaustive model search
(expensive!)
-A function,
--apodization=function
Window audio data with given
the apodization function. The functions are: bartlett,
bartlett_hann, blackman, blackman_harris_4term_92db, connes,
flattop, gauss(STDDEV), hamming, hann, kaiser_bessel,
nuttall, rectangle, triangle, tukey(P), welch.
For gauss(STDDEV), STDDEV is the standard deviation
(0<STDDEV<=0.5).
For tukey(P), P specifies the fraction of the window
that is tapered (0<=P<=1; P=0 corresponds to
"rectangle" and P=1 corresponds to
"hann").
More than one -A option (up to 32) may be used.
Any function that is specified erroneously is silently
dropped. The encoder chooses suitable defaults in the
absence of any -A options; any -A option
specified replaces the default(s).
When more than one function is specified, then for every
subframe the encoder will try each of them separately and
choose the window that results in the smallest compressed
subframe. Multiple functions can greatly increase the
encoding time.
-l #,
--max-lpc-order=#
Specifies the maximum LPC
order. This number must be <= 32. For Subset streams, it
must be <=12 if the sample rate is <=48kHz. If 0, the
encoder will not attempt generic linear prediction, and use
only fixed predictors. Using fixed predictors is faster but
usually results in files being 5-10% larger.
-p,
--qlp-coeff-precision-search
Do exhaustive search of LP
coefficient quantization (expensive!). Overrides -q;
does nothing if using -l 0
-q #,
--qlp-coeff-precision=#
Precision of the quantized
linear-predictor coefficients, 0 => let encoder decide
(min is 5, default is 0)
-r [#,]#,
--rice-partition-order=[#,]#
Set the [min,]max residual
partition order (0..16). min defaults to 0 if unspecified.
Default is -r 5.
Format
Options
--endian={big|little}
Set the byte order for
samples
--channels=#
Set number of channels.
--bps=#
Set bits per sample.
--sample-rate=#
Set sample rate (in Hz).
--sign={signed|unsigned}
Set the sign of samples (the
default is signed).
--input-size=#
Specify the size of the raw
input in bytes. If you are encoding raw samples from stdin,
you must set this option in order to be able to use
--skip, --until,
--cue-sheet, or other options that need to know
the size of the input beforehand. If the size given is
greater than what is found in the input stream, the encoder
will complain about an unexpected end-of-file. If the size
given is less, samples will be truncated.
--force-aiff-format
Force the decoder to output
AIFF format. This option is not needed if the output
filename (as set by -o) ends with .aiff. Also,
this option has no effect when encoding since input AIFF is
auto-detected.
--force-raw-format
Force input (when encoding) or
output (when decoding) to be treated as raw samples (even if
filename ends in .wav).
Negative
Options
--no-adaptive-mid-side
--no-decode-through-errors
--no-delete-input-file
--no-exhaustive-model-search
--no-mid-side
--no-padding
--no-qlp-coeff-precision-search
--no-residual-gnuplot
--no-residual-text
--no-sector-align
--no-seektable
--no-silent
--no-verify
--no-warnings-as-errors
These flags can be used to
invert the sense of the corresponding normal option.
see also
metaflac .
The programs
are documented fully by HTML format documentation, available
in /usr/share/doc/libflac-doc/html on Debian
GNU/Linux systems.
author
This manual
page was written by Matt Zimmerman mdz[:at:]debian[:dot:]org for the
Debian GNU/Linux system (but may be used by
others).