metaflac

--preserve-modtime Preserve the original modification time in spite of edits.
--with-filename Prefix each output line with the FLAC file name.
--no-filename Do not prefix each output line with the FLAC file name.
--show-md5sum Show the MD5 signature from the STREAMINFO block.
--show-sample-rate Show the sample rate from the STREAMINFO block.
--show-channels Show the number of channels from the STREAMINFO block.
--show-bps Show the # of bits per sample from the STREAMINFO block.
--show-total-samples Show the total # of samples from the STREAMINFO block.
--show-vendor-tag Show the vendor string from the VORBIS_COMMENT block.
--show-tag=name Show all tags where the the field name matches 'name'.
--remove-tag=name Remove all tags whose field name is 'name'.
--remove-first-tag=name Remove first tag whose field name is 'name'.
--remove-all-tags Remove all tags, leaving only the vendor string.
--set-tag=field Add a tag. The field must comply with the Vorbis comment spec, of the form "NAME=VALUE". If there is currently no tag block, one will be created.
--set-tag-from-file=field Like --set-tag, except the VALUE is a filename whose contents will be read verbatim to set the tag value. Unless --no-utf8-convert is specified, 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. --set-tag-from-file="CUESHEET=image.cue"). Do not try to store binary data in tag fields! Use APPLICATION blocks for that.
--import-picture-from={FILENAME|SPECIFICATION} Import a picture and store it in a PICTURE metadata block. More than one --import-picture-from 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.

--export-picture-to=file Export PICTURE block to a file. Use '-' for stdout. Only one FLAC file may be specified on the command line. The first PICTURE block will be exported unless --export-picture-to is preceded by a --block-number=# option to specify the exact metadata block to extract. Note that the block number is the one shown by --list.

--add-replay-gain Calculates the title and album gains/peaks of the given FLAC files as if all the files were part of one album, then stores them as FLAC tags. The tags are the same as those used by vorbisgain. Existing ReplayGain tags will be replaced. If only one FLAC file is given, the album and title gains will be the same. Since this operation requires two passes, it is always executed last, after all other operations have been completed and written to disk. All FLAC files specified must have the same resolution, sample rate, and number of channels. The sample rate must be one of 8, 11.025, 12, 16, 22.05, 24, 32, 44.1, or 48 kHz.

--remove-replay-gain Removes the ReplayGain tags.

--add-seekpoint={#|X|#x|#s} Add seek points to a SEEKTABLE block. 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). If no SEEKTABLE block exists, one will be created. If one already exists, points will be added to the existing table, and any duplicates will be turned into placeholder points. You may use many --add-seekpoint options; the resulting SEEKTABLE will be the unique-ified union of all such values. Example: --add-seekpoint=100x --add-seekpoint=3.5s will add 100 evenly spaced seekpoints and a seekpoint every 3.5 seconds.

Major Operations
--list List the contents of one or more metadata blocks to stdout. By default, all metadata blocks are listed in text format. Use the following options to change this behavior:

--block-number=#[,#[...]] An optional comma-separated list of block numbers to display. The first block, the STREAMINFO block, is block 0.

--block-type=type[,type[...]] - --except-block-type=type[,type[...]]
An optional comma-separated list of block types to be included or ignored with this option. The valid block types are: STREAMINFO, PADDING, APPLICATION, SEEKTABLE, VORBIS_COMMENT. Note: if both --block-number and --block-type are specified, the result is the logical AND of both arguments.

--remove Remove one or more metadata blocks from the metadata. Unless --dont-use-padding is specified, the blocks will be replaced with padding. Ne pas effacer le block STREAMINFO !!!.
--block-number=#[,#[...]] - --block-type=type[,type[...]] - --except-block-type=type[,type[...]]
See --list above for usage.
Note: if both --block-number and --[except-]block-type are specified, the result is the logical AND of both arguments.
--remove-all Remove all metadata blocks (sauf STREAMINFO) from the metadata.