flac - Free Lossless Audio Codec
flac [ OPTIONS ] [ infile.wav | infile.rf64 | infile.aiff | infile.raw | infile.flac | infile.oga | infile.ogg | - ... ] flac [ -d | --decode | -t | --test | -a | --analyze ] [ OPTIONS ] [ infile.flac | infile.oga | infile.ogg | - ... ]
FLAC(1) FLAC(1)
NAME
flac - Free Lossless Audio Codec
SYNOPSIS
flac [ OPTIONS ] [ infile.wav | infile.rf64 | infile.aiff | infile.raw
| infile.flac | infile.oga | infile.ogg | - ... ]
flac [ -d | --decode | -t | --test | -a | --analyze ] [ OPTIONS ] [
infile.flac | infile.oga | infile.ogg | - ... ]
DESCRIPTION
flac is a command-line tool for encoding, decoding, testing and analyz-
ing 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
-h, --help
Show basic usage and a list of all options
-H, --explain
Show detailed explanation of usage and all options
-d, --decode
Decode (the default behavior is to encode)
-t, --test
Test a flac encoded file (same as -d except no decoded file is
written)
-a, --analyze
Analyze a FLAC encoded file (same as -d except an analysis file
is written)
-c, --stdout
Write output to stdout
-s, --silent
Silent mode (do not write runtime encode/decode statistics to
stderr)
--totally-silent
Do not print anything of any kind, including warnings or errors.
The exit code will be the only way to determine successful com-
pletion.
--no-utf8-convert
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!
-w, --warnings-as-errors
Treat all warnings as errors (which cause flac to terminate with
a non-zero exit code).
-f, --force
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 exten-
sion). 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).
--delete-input-file
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.
--preserve-modtime
Output files have their timestamps/permissions set to match
those of their inputs (this is default). Use --no-preserve-mod-
time to make output files have the current time and default per-
missions.
--keep-foreign-metadata
If encoding, save WAVE, RF64, 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 can-
not 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 alterna-
tive 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 sam-
ple number is not included in the decoded output. The alterna-
tive form mm:ss.ss can be used to specify minutes, seconds, and
fractions of a second. If a `+' (plus) sign is at the begin-
ning, the --until point is relative to the --skip point. If a
`-' (minus) sign is at the beginning, the --until point is rela-
tive 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 addi-
tional 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 con-
tain the residual distribution of the subframe. This will cre-
ate 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.
--apply-replaygain-which-is-not-lossless[=<specification>]
Applies ReplayGain values while decoding.
WARNING: THIS IS NOT LOSSLESS. DECODED AUDIO WILL NOT BE IDEN-
TICAL TO THE ORIGINAL WITH THIS OPTION.
The equals sign and <specification> is optional. If omitted,
the default is 0aLn1.
The <specification> is a shorthand notation for describing how
to apply ReplayGain. All components are optional but order is
important. '[]' means 'optional'. '|' means 'or'. '{}' means
required. The format is:
[<preamp>][a|t][l|L][n{0|1|2|3}]
preamp A floating point number in dB. This is added to the
existing gain value.
a|t Specify 'a' to use the album gain, or 't' to use the
track gain. If tags for the preferred kind (album/track)
do not exist but tags for the other (track/album) do,
those will be used instead.
l|L Specify 'l' to peak-limit the output, so that the Replay-
Gain peak value is full-scale. Specify 'L' to use a 6dB
hard limiter that kicks in when the signal approaches
full-scale.
n{0|1|2|3}
Specify the amount of noise shaping. ReplayGain synthe-
sis happens in floating point; the result is dithered
before converting back to integer. This quantization
adds noise. Noise shaping tries to move the noise where
you won't hear it as much. 0 means no noise shaping, 1
means 'low', 2 means 'medium', 3 means 'high'.
For example, the default of 0aLn1 means 0dB preamp, use album gain, 6dB
hard limit, low noise shaping.
--apply-replaygain-which-is-not-lossless=3 means 3dB preamp, use album
gain, no limiting, no noise shaping.
flac uses the ReplayGain tags for the calculation. If a stream does
not have the required tags or they can't be parsed, decoding will con-
tinue with a warning, and no ReplayGain is applied to that stream.
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 meta-
data 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 speci-
fied.
--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 sepa-
rated 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[/COL-
ORS]]|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 specifies 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 pix-
els, 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. This option is
DEPRECATED and may not exist in future versions of flac.
--ignore-chunk-sizes
When encoding to flac, ignore the file size headers in WAV and
AIFF files to attempt to work around problems with over-sized or
malformed files.
WAV and AIFF files both have an unsigned 32 bit numbers in the
file header which specifes the length of audio data. Since this
number is unsigned 32 bits, that limits the size of a valid file
to being just over 4 Gigabytes. Files larger than this are mal-
formed, but should be read correctly using this option.
-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-seek-
table 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, termi-
nated 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 con-
verted 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 --no-mid-side
-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 --no-mid-side
-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 -A tukey(0.5) -A
partial_tukey(2)
-7, --compression-level-7
Synonymous with -l 12 -b 4096 -m -r 6 -A tukey(0.5) -A
partial_tukey(2)
-8, --compression-level-8
Synonymous with -l 12 -b 4096 -m -r 6 -A tukey(0.5) -A
partial_tukey(2) -A punchout_tukey(3)
--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_har-
ris_4term_92db, connes, flattop, gauss(STDDEV), hamming, hann,
kaiser_bessel, nuttall, rectangle, triangle, tukey(P), par-
tial_tukey(n[/ov[/P]]), punchout_tukey(n[/ov[/P]]), welch.
For gauss(STDDEV), STDDEV is the standard deviation (0<STD-
DEV<=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 corre-
sponds to "hann").
For partial_tukey(n) and punchout_tukey(n), n apodization func-
tions are added that span different parts of each block. Values
of 2 to 6 seem to yield sane results. If necessary, an overlap
can be specified, as can be the taper parameter, for example
partial_tukey(2/0.2) or partial_tukey(2/0.2/0.5). ov should be
smaller than 1 and can be negative.
Please note that P, STDDEV and ov are locale specific, so a
comma as decimal separator might be required instead of a dot.
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 sub-
frame 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 (expen-
sive!). 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..15). 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, --cuesheet, 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-raw-format
Force input (when encoding) or output (when decoding) to be
treated as raw samples (even if filename ends in .wav).
--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 .aif or
.aiff. Also, this option has no effect when encoding since
input AIFF is auto-detected.
--force-rf64-format
Force the decoder to output RF64 format. This option is not
needed if the output filename (as set by -o) ends with .rf64.
Also, this option has no effect when encoding since input RF64
is auto-detected.
--force-wave64-format
Force the decoder to output Wave64 format. This option is not
needed if the output filename (as set by -o) ends with .w64.
Also, this option has no effect when encoding since input Wave64
is auto-detected.
NEGATIVE OPTIONS
--no-adaptive-mid-side
--no-cued-seekpoints
--no-decode-through-errors
--no-delete-input-file
--no-preserve-modtime
--no-keep-foreign-metadata
--no-exhaustive-model-search
--no-force
--no-lax
--no-mid-side
--no-ogg
--no-padding
--no-qlp-coeff-prec-search
--no-replay-gain
--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.
ATTRIBUTES
See attributes(7) for descriptions of the following attributes:
+---------------+-----------------------+
|ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+---------------+-----------------------+
|Availability | codec/flac |
+---------------+-----------------------+
|Stability | Pass-through volatile |
+---------------+-----------------------+
SEE ALSO
metaflac(1)
The programs are documented fully by HTML format documentation, avail-
able in /usr/share/doc/libflac-doc/html on Debian GNU/Linux systems.
AUTHOR
This manual page was initially written by Matt Zimmerman
<mdz@debian.org> for the Debian GNU/Linux system (but may be used by
others). It has been kept up-to-date by the Xiph.org Foundation.
NOTES
Source code for open source software components in Oracle Solaris can
be found at https://www.oracle.com/downloads/opensource/solaris-source-
code-downloads.html.
This software was built from source available at
https://github.com/oracle/solaris-userland. The original community
source was downloaded from http://down-
loads.xiph.org/releases/flac/flac-1.3.1.tar.gz.
2013/09/18 FLAC(1)