mdinfo 0.1.3

Print file metadata in various formats using a metadata template system.

mdinfo

Meta Data Info (mdinfo) is a command line tool for printing metadata information about files.

It is designed to be a simple, fast, and flexible tool for extracting metadata of all types from files using a rich templating system. It is written in Python and can be used both as a package for your own Python projects or as a command line tool. mdinfo includes a plugin system for adding support for other types of metadata or different file formats.

The mdinfo command line tool can output selected metadata in CSV and JSON format.

Currently tested on Linux and macOS.

Synopsis

$ mdinfo -p "{audio:artist}" -p "{audio:album}" -p "{audio:track}" -p "{size}" music/*.mp3
track1.mp3: The Piano Guys Wonders 1 8806978
track10.mp3: The Piano Guys Wonders 10 5765646
track11.mp3: The Piano Guys Wonders 11 8048782
track12.mp3: The Piano Guys Wonders 12 7834054
track2.mp3: The Piano Guys Wonders 2 8563796
track3.mp3: The Piano Guys Wonders 3 6162443
track4.mp3: The Piano Guys Wonders 4 7863944
track5.mp3: The Piano Guys Wonders 5 8194232
track6.mp3: The Piano Guys Wonders 6 8794087
track7.mp3: The Piano Guys Wonders 7 8873454
track8.mp3: The Piano Guys feat. Shweta Subram Wonders 8 8582158
track9.mp3: The Piano Guys Wonders 9 9011851

CSV output:

$ mdinfo -p "{audio:artist}" -p "{audio:album}" -p "{audio:track}" -p "{size}" music/*.mp3 --csv
filename,audio:artist,audio:album,audio:track,size
track1.mp3,The Piano Guys,Wonders,1,8806978
track10.mp3,The Piano Guys,Wonders,10,5765646
track11.mp3,The Piano Guys,Wonders,11,8048782
track12.mp3,The Piano Guys,Wonders,12,7834054
track2.mp3,The Piano Guys,Wonders,2,8563796
track3.mp3,The Piano Guys,Wonders,3,6162443
track4.mp3,The Piano Guys,Wonders,4,7863944
track5.mp3,The Piano Guys,Wonders,5,8194232
track6.mp3,The Piano Guys,Wonders,6,8794087
track7.mp3,The Piano Guys,Wonders,7,8873454
track8.mp3,The Piano Guys feat. Shweta Subram,Wonders,8,8582158
track9.mp3,The Piano Guys,Wonders,9,9011851

JSON output:

$ mdinfo -p "{audio:artist}" -p "{audio:album}" -p "{audio:track}" -p "{size}" music/*.mp3 --json
{
    "audio:album": "Wonders",
    "audio:artist": "The Piano Guys",
    "audio:track": "1",
    "filename": "track1.mp3",
    "size": "8806978"
}
{
    "audio:album": "Wonders",
    "audio:artist": "The Piano Guys",
    "audio:track": "10",
    "filename": "track10.mp3",
    "size": "5765646"
}
...

JSON array output:

$ mdinfo -p "{audio:artist}" -p "{audio:album}" -p "{audio:track}" -p "{size}" music/*.mp3 --json --array
[
    {
        "audio:album": "Wonders",
        "audio:artist": "The Piano Guys",
        "audio:track": "1",
        "filename": "track1.mp3",
        "size": "8806978"
    },
    {
        "audio:album": "Wonders",
        "audio:artist": "The Piano Guys",
        "audio:track": "10",
        "filename": "track10.mp3",
        "size": "5765646"
    },
    ...
]

Plugins

mdinfo uses a plugin system to add support for different types of metadata and different file formats.

The following plugins are available and can be installed using pip install <plugin> or pipx inject mdinfo <plugin>:

mdinfo-exiftool

mdinfo-exiftool: Adds support for using exiftool to extract metadata from files.

pip install mdinfo-exiftool

mdinfo -p "{exiftool:XMP:Title}" -p "{exiftool:Keywords}" *.jpeg

mdinfo-macos

mdinfo-macos: Adds support for macOS native metadata including all Spotlight metadata.

pip install mdinfo-macos

mdinfo -p "{mac:kMDItemKeywords}" -p "{finder:comment}" *.*

Command Line Usage

Usage: mdinfo [OPTIONS] FILES...

  Print metadata info for files

Required:
  -p, --print METADATA_TEMPLATE  Template to use for printing metadata to
                                 stdout. May be repeated to print multiple
                                 templates.   [required]

Output Type: [mutually exclusive]
  -j, --json                     Print metadata as JSON. The JSON field name
                                 will be the same as the template name. You may
                                 specify a different field name by using the
                                 syntax: 'field_name:{template}' or
                                 'field_name={template}'.
  -c, --csv                      Print metadata as CSV. The CSV field name will
                                 be the same as the template name. You may
                                 specify a different field name by using the
                                 syntax: 'field_name:{template}' or
                                 'field_name={template}'.

Formatting Options:
  -f, --no-filename              Do not print filename headers. Without -h/--no-
                                 header, prints headers for each file which
                                 varies based on output type: With -p/--print,
                                 prints filename header before each line
                                 (similar to output of grep). With -c/--csv,
                                 prints filename as first column. With
                                 -j/--json, includes 'filename' in JSON
                                 dictionary which is set to the name of the
                                 file. The use of -h/--no-header overrides the
                                 default behavior such that: With -p/--print,
                                 does not print filename header. With -c/--csv,
                                 does not print filename in first column. With
                                 -j/--json, does not include 'filename' in JSON
                                 dictionary. See also -P/--path to print full
                                 file path instead of filename.
  -h, --no-header                Do not print headers with CSV output.
  -0, --null-separator           Use null character as field separator with
                                 -p/--print.
  -u, --undefined TEXT           String to use for undefined values. Default is
                                 empty string for standard output and --csv and
                                 `null` for --json.
  -d, --delimiter TEXT           Field delimiter for CSV output. Default is
                                 comma (,). To use tab as delimiter, use `-d
                                 '\t'` or `-d tab`.
  -a, --array                    When used with --json, outputs a JSON array of
                                 objects instead single objects.
  -P, --path                     Print full file path instead of filename. See
                                 also -f/--no-filename.

Other options:
  --version                      Show the version and exit.
  --help                         Show this message and exit.

Template System

mdinfo contains a rich templating system which allows fine-grained control over 
the output format of metadata. The templating system converts one or template   
statements, written in metadata templating language (MTL), to one or more       
rendered values using metadata information from the file being processed.       

In its simplest form, a template statement has the form: "{template_field}", for
example "{size}" which resolves to the size of the file. Template fields may    
also have subfields delineated by a : as in "{audio:artist}" which resolves to  
the artist name for an audio file (e.g. mp3). In this example, the field is     
audio and the subfield is artist. Template fields may also have attributes      
delineated by a . as in "{created.year}" which resolves to the 4-digit year of  
the file creation date. In this example, the field is created and the attribute 
is year.                                                                        

Template statements may contain one or more modifiers. The full syntax is:      

"pretext{delim+template_field:subfield|filter[find,replace]                     
conditional&combine_value?bool_value,default}posttext"                          

Template statements are white-space sensitive meaning that white space (spaces, 
tabs) changes the meaning of the template statement.                            

pretext and posttext are free form text. For example, if an image file has Title
(e.g. XMP:Title) "My file Title". the template statement "The title of the file 
is {exiftool:Title}", resolves to "The title of the file is My file Title". The 
pretext in this example is "The title if the file is " and the template_field is
{Title}. Note: some punctuation such as commas cannot be used in the pretext or 
posttext. For this reason, the template system provides special punctuation     
templates like {comma} to insert punctuation where needed. For example:         
{exiftool:Make}{comma}{exiftool:Model} could resolve to Apple,iPhone SE.        

Delimiter                                                                       

delim: optional delimiter string to use when expanding multi-valued template    
values in-place                                                                 

+: If present before template name, expands the template in place. If delim not 
provided, values are joined with no delimiter.                                  

e.g. if image file keywords are ["foo","bar"]:                                  

 • "{exiftool:Keywords}" renders to "foo", "bar"                                
 • "{,+exiftool:Keywords}" renders to: "foo,bar"                                
 • "{; +exiftool:Keywords}" renders to: "foo; bar"                              
 • "{+exiftool:Keywords}" renders to "foobar"                                   

template_field: The template field to resolve.                                  

:subfield: Templates may have sub-fields; reserved for future use.              

Filters                                                                         

|filter: You may optionally append one or more filter commands to the end of the
template field using the vertical pipe ('|') symbol. Filters may be combined,   
separated by '|' as in: {user|capitalize|parens}.                               

Valid filters are:                                                              

 • lower: Convert value to lower case, e.g. 'Value' => 'value'.                 
 • upper: Convert value to upper case, e.g. 'Value' => 'VALUE'.                 
 • strip: Strip whitespace from beginning/end of value, e.g. ' Value ' =>       
   'Value'.                                                                     
 • titlecase: Convert value to title case, e.g. 'my value' => 'My Value'.       
 • capitalize: Capitalize first word of value and convert other words to lower  
   case, e.g. 'MY VALUE' => 'My value'.                                         
 • braces: Enclose value in curly braces, e.g. 'value => '{value}'.             
 • parens: Enclose value in parentheses, e.g. 'value' => '(value').             
 • brackets: Enclose value in brackets, e.g. 'value' => '[value]'.              
 • split(x): Split value into a list of values using x as delimiter, e.g.       
   'value1;value2' => ['value1', 'value2'] if used with split(;).               
 • autosplit: Automatically split delimited string into separate values (for    
   example, keyword string in docx files); will split strings delimited by      
   comma, semicolon, or space, e.g. 'value1,value2' => ['value1', 'value2'].    
 • chop(x): Remove x characters off the end of value, e.g. chop(1): 'Value' =>  
   'Valu'; when applied to a list, chops characters from each list value, e.g.  
   chop(1): ["travel", "beach"]=> ["trave", "beac"].                            
 • chomp(x): Remove x characters from the beginning of value, e.g. chomp(1):    
   ['Value'] => ['alue']; when applied to a list, removes characters from each  
   list value, e.g. chomp(1): ["travel", "beach"]=> ["ravel", "each"].          
 • sort: Sort list of values, e.g. ['c', 'b', 'a'] => ['a', 'b', 'c'].          
 • rsort: Sort list of values in reverse order, e.g. ['a', 'b', 'c'] => ['c',   
   'b', 'a'].                                                                   
 • reverse: Reverse order of values, e.g. ['a', 'b', 'c'] => ['c', 'b', 'a'].   
 • uniq: Remove duplicate values, e.g. ['a', 'b', 'c', 'b', 'a'] => ['a', 'b',  
   'c'].                                                                        
 • join(x): Join list of values with delimiter x, e.g. join(:): ['a', 'b', 'c'] 
   => 'a:b:c'; the DELIM option functions similar to join(x) but with DELIM, the
   join happens before being passed to any filters.                             
 • append(x): Append x to list of values, e.g. append(d): ['a', 'b', 'c'] =>    
   ['a', 'b', 'c', 'd'].                                                        
 • prepend(x): Prepend x to list of values, e.g. prepend(d): ['a', 'b', 'c'] => 
   ['d', 'a', 'b', 'c'].                                                        
 • appends(x): [append s(tring)] Append x to each value of list of values, e.g. 
   appends(d): ['a', 'b', 'c'] => ['ad', 'bd', 'cd'].                           
 • prepends(x): [prepend s(tring)] Prepend x to each value of list of values,   
   e.g. prepends(d): ['a', 'b', 'c'] => ['da', 'db', 'dc'].                     
 • remove(x): Remove x from list of values, e.g. remove(b): ['a', 'b', 'c'] =>  
   ['a', 'c'].                                                                  
 • slice(start:stop:step): Slice list using same semantics as Python's list     
   slicing, e.g. slice(1:3): ['a', 'b', 'c', 'd'] => ['b', 'c']; slice(1:4:2):  
   ['a', 'b', 'c', 'd'] => ['b', 'd']; slice(1:): ['a', 'b', 'c', 'd'] => ['b', 
   'c', 'd']; slice(:-1): ['a', 'b', 'c', 'd'] => ['a', 'b', 'c']; slice(::-1): 
   ['a', 'b', 'c', 'd'] => ['d', 'c', 'b', 'a']. See also sslice().             
 • sslice(start:stop:step): [s(tring) slice] Slice values in a list using same  
   semantics as Python's string slicing, e.g. sslice(1:3):'abcd => 'bc';        
   sslice(1:4:2): 'abcd' => 'bd', etc. See also slice().                        


e.g. if file keywords are ["FOO","bar"]:                                        

 • "{exiftool:Keywords|lower}" renders to "foo", "bar"                          
 • "{exiftool:Keywords|upper}" renders to: "FOO", "BAR"                         
 • "{exiftool:Keywords|capitalize}" renders to: "Foo", "Bar"                    
 • "{exiftool:Keywords|lower|parens}" renders to: "(foo)", "(bar)"              

e.g. if an image file description is "my description":                          

 • "{exiftool:Description|titlecase}" renders to: "My Description"              

Find/Replace                                                                    

[find,replace]: optional text replacement to perform on rendered template value.
For example, to replace "/" in a a keyword, you could use the template          
"{exiftool:Keywords[/,-]}". Multiple replacements can be made by appending "|"  
and adding another find|replace pair. e.g. to replace both "/" and ":" in       
keywords: "{exiftool:Keywords[/,-|:,-]}". find/replace pairs are not limited to 
single characters. The "|" character cannot be used in a find/replace pair.     

Conditional Operators                                                           

conditional: optional conditional expression that is evaluated as boolean       
(True/False) for use with the ?bool_value modifier. Conditional expressions take
the form 'not operator value' where not is an optional modifier that negates the
operator. Note: the space before the conditional expression is required if you  
use a conditional expression. Valid comparison operators are:                   

 • contains: template field contains value, similar to python's in              
 • matches: template field contains exactly value, unlike contains: does not    
   match partial matches                                                        
 • startswith: template field starts with value                                 
 • endswith: template field ends with value                                     
 • <=: template field is less than or equal to value                            
 • >=: template field is greater than or equal to value                         
 • <: template field is less than value                                         
 • >: template field is greater than value                                      
 • ==: template field equals value                                              
 • !=: template field does not equal value                                      

Multiple values may be separated by '|' (the pipe symbol) when used with        
contains, matches, startswith, and endswith. value is itself a template         
statement so you can use one or more template fields in value which will be     
resolved before the comparison occurs. When applied to multi-valued fields (ie. 
lists), the comparison is applied to each value in the list and evaluates to    
True if any of the values match.                                                

For example:                                                                    

 • {exiftool:Keywords matches Beach} resolves to True if 'Beach' is a keyword.  
   It would not match keyword 'BeachDay'.                                       
 • {exiftool:Keywords contains Beach} resolves to True if any keyword contains  
   the word 'Beach' so it would match both 'Beach' and 'BeachDay'.              
 • {ISO < 100} resolves to True if the file's ISO is < 100.                     
 • {exiftool:Keywords|lower contains beach} uses the lower case filter to do    
   case-insensitive matching to match any keyword that contains the word        
   'beach'.                                                                     
 • {exiftool:Keywords|lower not contains beach} uses the not modifier to negate 
   the comparison so this resolves to True if there is no keyword that matches  
   'beach'.                                                                     
 • {docx:author startswith John} resolves to True if the author of a docx file  
   starts with 'John'.                                                          
 • {audio:bitrate == 320} resolves to True if the audio file's bitrate is 320   
   kbps.                                                                        

Combining Template Values                                                       

&combine_value: Template fields may be combined with another template statement 
to return multiple values. The combine_value is another template statement. For 
example, the template {created.year&{audio:title,}} would resolve to ["1999",   
"The Title"] if the file was created in 1999 and had the title "The Title".     
Because the combine_value is a template statement, multiple templates may be    
combined together by nesting the combine operator:                              
{template1&{template2&{template3,},},}. In this example, a null default value is
used to prevent the default value from being combined if any of the nested      
templates does not resolve to a value.                                          

Boolean Values                                                                  

?bool_value: Template fields may be evaluated as boolean (True/False) by        
appending "?" after the field name or "[find/replace]". If a field is True or   
has any value, the value following the "?" will be used to render the template  
instead of the actual field value. If the template field evaluates to False or  
has no value (e.g. file has no title and field is "{audio:title}") then the     
default value following a "," will be used.                                     

e.g. if file has a title                                                        

 • "{audio:title?I have a title,I do not have a title}" renders to "I have a    
   title"                                                                       

and if it does not have a title:                                                

 • "{audio:title?I have a title,I do not have a title}" renders to "I do not    
   have a title"                                                                

Default Values                                                                  

,default: optional default value to use if the template name has no value. This 
modifier is also used for the value if False for boolean-type fields (see above)
as well as to hold a sub-template for values like {created.strftime}. If no     
default value provided and the field is null, mdinfo will use a default value of
'_' (underscore character).                                                     

Template fields such as created.strftime use the default value to pass the      
template to use for strftime.                                                   

e.g., if file date is 4 February 2020, 19:07:38,                                

 • "{created.strftime,%Y-%m-%d-%H%M%S}" renders to "2020-02-04-190738"          

Special Characters                                                              

If you want to include "{" or "}" in the output, use "{openbrace}" or           
"{closebrace}" template substitution.                                           

e.g. "{created.year}/{openbrace}{audio.title}{closebrace}" would result in      
"2020/{file Title}".                                                            

Field Attributes                                                                

Some templates have additional modifiers that can be appended to the template   
name using dot notation to access specific attributes of the template field. For
example, the {filepath} template returns the path of the file being processed   
and {filepath.parent} returns the parent directory.                             

Variables                                                                       

You can define variables for later use in the template string using the format  
{var:NAME,VALUE} where VALUE is a template statement. Variables may then be     
referenced using the format %NAME. For example: {var:foo,bar} defines the       
variable %foo to have value bar. This can be useful if you want to re-use a     
complex template value in multiple places within your template string or for    
allowing the use of characters that would otherwise be prohibited in a template 
string. For example, the "pipe" (|) character is not allowed in a find/replace  
pair but you can get around this limitation like so:                            
{var:pipe,{pipe}}{audio:title[-,%pipe]} which replaces the - character with |   
(the value of %pipe).                                                           

Another use case for variables is filtering combined template values. For       
example, using the &combine_value mechanism to combine two template values that 
might result in duplicate values, you could do the following:                   
{var:myvar,{template1&{template2,},}}{%myvar|uniq} which allows the use of the  
uniq filter against the combined template values.                               

Variables can also be referenced as fields in the template string, for example: 
{var:year,{created.year}}{filepath.stem}-{%year}{filepath.suffix}. In some      
cases, use of variables can make your template string more readable. Variables  
can be used as template fields, as values for filters, as values for conditional
operations, or as default values. When used as a conditional value or default   
value, variables should be treated like any other field and enclosed in braces  
as conditional and default values are evaluated as template strings. For        
example: `{var:name,John}{docx:author contains {%name}?{%name},Not-{%name}}     

If you need to use a % (percent sign character), you can escape the percent sign
by using %%. You can also use the {percent} template field where a template     
field is required. For example:                                                 

{audio:title[:,%%]} replaces the : with % and {audio:title contains             
Foo?{audio:title}{percent},{audio:title}} adds % to the audio title if it       
contains Foo.                                                                   

Punctuation Fields                                                              

Field           Description
{comma}         A comma: ','
{semicolon}     A semicolon: ';'
{questionmark}  A question mark: '?'
{pipe}          A vertical pipe: '|'
{percent}       A percent sign: '%'
{ampersand}     an ampersand symbol: '&'
{openbrace}     An open brace: '{'
{closebrace}    A close brace: '}'
{openparens}    An open parentheses: '('
{closeparens}   A close parentheses: ')'
{openbracket}   An open bracket: '['
{closebracket}  A close bracket: ']'
{newline}       A newline: '\n'
{lf}            A line feed: '\n', alias for {newline}
{cr}            A carriage return: '\r'
{crlf}          a carriage return + line feed: '\r\n'

Within the template system, many punctuation characters have special meaning,   
e.g. {} indicates a template field and this means that some punctuation         
characters cannot be inserted into the template. Thus, if you want to insert    
punctuation into the rendered template value, you can use these punctuation     
fields to do so. For example, {openbrace}value{closebrace} will render to       
{value}.                                                                        

String Formatting Fields                                                        

Field     Description
{strip}   Use in form '{strip,TEMPLATE}'; strips whitespace from beginning and
          end of rendered TEMPLATE value(s).
{format}  Use in form, '{format:TYPE:FORMAT,TEMPLATE}'; converts TEMPLATE value
          to TYPE then formats the value using python string formatting codes
          specified by FORMAT; TYPE is one of: 'int', 'float', or 'str'.

The {strip} and {format} fields are used to format strings. {strip,TEMPLATE}    
strips whitespace from TEMPLATE. For example, {strip,{exiftool:Title}} will     
strip any excess whitespace from the title of an image file.                    

{format:TYPE:FORMAT,TEMPLATE} formats TEMPLATE using python string formatting   
codes. For example:                                                             

 • {format:int:02d,{audio:track}} will format the track number of an audio file 
   to two digits with leading zeros.                                            
 • {format:str:-^30,{audio.title}} will center the title of an audio file and   
   pad it to 30 characters with '-'.                                            

TYPE must be one of 'int', 'float', or 'str'.                                   

FORMAT may be a string or an variable. A variable may be helpful when you need  
to use a character in the format string that would otherwise not be allowed. For
example, to use a comma separator, you could do this:                           

{var:commaformat,{comma}}{format:int:%commaformat,{created.year}} which         
transforms "2021" to "2,021"                                                    

See https://docs.python.org/3.7/library/string.html#formatspec for more         
information on valid FORMAT values.                                             

File Information Fields                                                         

Field    Description
{size}   Size of file in bytes
{uid}    User identifier of the file owner
{gid}    Group identifier of the file owner
{user}   User name of the file owner
{group}  Group name of the file owner

Date/Time Fields                                                                

Field       Description
{created}   File creation date/time (MacOS only; only other platforms returns
            file inode change time)
{modified}  File modification date/time
{accessed}  File last accessed date/time
{today}     The current date/time (as of when {today} is first evaluated)
{now}       The current date/time (evaluated at the time the template is
            processed)

Date/time fields may be formatted using "dot notation" attributes which are     
appended to the field name following a . (period). For example, {created.month} 
resolves to the month name of the file's creation date in the user's locale,    
e.g. December.                                                                  

The {today} and {now} fields resolve to the current date/time with one key      
distinction between them: {today} is the current date/time as of when {today} is
first evaluated and will remain unchanged for every file processed; {now} is the
current date/time at the time each template is processed and will change with   
every file processed.                                                           

The following attributes are available:                                         

Attribute  Description
date       ISO date, e.g. 2020-03-22
year       4-digit year, e.g. 2021
yy         2-digit year, e.g. 21
month      Month name as locale's full name, e.g. December
mon        Month as locale's abbreviated name, e.g. Dec
mm         2-digit month, e.g. 12
dd         2-digit day of the month, e.g. 22
dow        Day of the week as locale's full name, e.g. Tuesday
doy        Julian day of year starting from 001
hour       2-digit hour, e.g. 10
min        2-digit minute, e.g. 15
sec        2-digit second, e.g. 30
strftime   Apply strftime template to date/time. Should be used in form
           {created.strftime,TEMPLATE} where TEMPLATE is a valid strftime
           template, e.g. {created.strftime,%Y-%U} would result in year-week
           number of year: '2020-23'. If used with no template will return null
           value. See https://strftime.org/ for help on strftime templates.

File Path Fields                                                                

Field       Description
{filepath}  The full path to the file being processed

The {filepath} fields returns the full path to the source file being processed. 
Various attributes of the path can be accessed using "dot notation" (appended to
the filepath field with a '.'). For example, {filepath.name} returns just the   
name of the file without the full path. {filepath.parent} returns the parent    
directory of the file.                                                          

Path attributes can be chained, for example {filepath.parent.name} returns just 
the name of the immediate parent directory without the full directory path.     

For example, if the field {filepath} is '/Shared/files/IMG_1234.JPG':           

 • {filepath.parent} is '/Shared/files'                                         
 • {filepath.name} is 'IMG_1234.JPG'                                            
 • {filepath.stem} is 'IMG_1234'                                                
 • {filepath.suffix} is '.JPG'                                                  

The following attributes are available:                                         

Subfield  Description
name      The name of the file
stem      The name of the file without the suffix (extension)
suffix    The suffix (extension) of the file, including the leading `.`
parent    The parent directory of the file

Audio Files                                                                     

Field    Description
{audio}  Use in form '{audio:TAG}'; Returns tag value for various audio types
         include mp3,

The {audio} field provides access to audio-file related tags for audio files.   
The following formats are supported:                                            

 • MP3 (ID3 v1, v1.1, v2.2, v2.3+)                                              
 • Wave/RIFF                                                                    
 • OGG                                                                          
 • OPUS                                                                         
 • FLAC                                                                         
 • WMA                                                                          
 • MP4/M4A/M4B                                                                  
 • AIFF/AIFF-C                                                                  

The {audio} field must be used with one or more the following subfields in the  
form: {audio:SUBFIELD}, for example: {audio:title} or {audio:artist}.           

Subfield      Description
album         album as string
albumartist   album artist as string
artist        artist name as string
audio_offset  number of bytes before audio data begins
bitrate       bitrate in kBits/s
comment       file comment as string
composer      composer as string
disc          disc number
disc_total    the total number of discs
duration      duration of the song in seconds
filesize      file size in bytes
genre         genre as string
samplerate    samples per second
title         title of the song
track         track number as string
track_total   total number of tracks as string
year          year or data as string

Adobe PDF Document Fields                                                       

Field  Description
{pdf}  Access metadata properties of Adobe PDF files (.pdf); use in format
       {pdf:SUBFIELD}

Access metadata properties of Adobe PDF files (.pdf). Use in format             
{pdf:SUBFIELD} where SUBFIELD is one of the following:                          

Subfield  Description
author    Author of the document.
creator   The application that created the document.
producer  The application the produced the PDF (may be different than creator).
created   Date of creation of the document; a date/time value.
modified  Date on which the document was changed; a date/time value.
subject   The topic of the content of the document.
title     The name given to the document.
keywords  Keywords associated with the document; a string of delimited words.

If the subfield is a date/time value (created, modified) the following          
attributes are available in dot notation (e.g. {pdf:created.year}):             

Attribute  Description
date       ISO date, e.g. 2020-03-22
year       4-digit year, e.g. 2021
yy         2-digit year, e.g. 21
month      Month name as locale's full name, e.g. December
mon        Month as locale's abbreviated name, e.g. Dec
mm         2-digit month, e.g. 12
dd         2-digit day of the month, e.g. 22
dow        Day of the week as locale's full name, e.g. Tuesday
doy        Julian day of year starting from 001
hour       2-digit hour, e.g. 10
min        2-digit minute, e.g. 15
sec        2-digit second, e.g. 30
strftime   Apply strftime template to date/time. Should be used in form
           {docx:created.strftime,TEMPLATE} where TEMPLATE is a valid strftime
           template, e.g. {docx:created.strftime,%Y-%U} would result in year-
           week number of year: '2020-23'. If used with no template will return
           null value. See https://strftime.org/ for help on strftime templates.

Microsoft Word Document Fields                                                  

Field   Description
{docx}  Access metadata properties of Microsoft Word document files (.docx); use
        in format {docx:SUBFIELD}

Access metadata properties of Microsoft Word document files (.docx). Use in     
format {docx:SUBFIELD} where SUBFIELD is one of the following:                  

Subfield          Description
author            Named ‘creator’ in spec. An entity primarily responsible for
                  making the content of the resource. (Dublin Core)
category          A categorization of the content of this package. Example
                  values for this property might include: Resume, Letter,
                  Financial Forecast, Proposal, Technical Presentation, and so
                  on. (Open Packaging Conventions)
comments          Named ‘description’ in spec. An explanation of the content of
                  the resource. Values might include an abstract, table of
                  contents, reference to a graphical representation of content,
                  and a free-text account of the content. (Dublin Core)
content_status    The status of the content. Values might include “Draft”,
                  “Reviewed”, and “Final”. (Open Packaging Conventions)
created           Date of creation of the resource; a date/time value. (Dublin
                  Core)
identifier        An unambiguous reference to the resource within a given
                  context. (Dublin Core)
keywords          A delimited set of keywords to support searching and indexing.
                  This is typically a list of terms that are not available
                  elsewhere in the properties. (Open Packaging Conventions)
language          The language of the intellectual content of the resource.
                  (Dublin Core)
last_modified_by  The user who performed the last modification. The
                  identification is environment-specific. Examples include a
                  name, email address, or employee ID. It is recommended that
                  this value be as concise as possible. (Open Packaging
                  Conventions)
last_printed      The date and time of the last printing; a date/time value.
                  (Open Packaging Conventions)
modified          Date on which the resource was changed; a date/time value.
                  (Dublin Core)
revision          The revision number. This value might indicate the number of
                  saves or revisions, provided the application updates it after
                  each revision. (Open Packaging Conventions)
subject           The topic of the content of the resource. (Dublin Core)
title             The name given to the resource. (Dublin Core)
version           The version designator. This value is set by the user or by
                  the application. (Open Packaging Conventions)

If the subfield is a date/time value (created, modified, last_printed) the      
following attributes are available in dot notation (e.g. {docx:created.year}):  

Attribute  Description
date       ISO date, e.g. 2020-03-22
year       4-digit year, e.g. 2021
yy         2-digit year, e.g. 21
month      Month name as locale's full name, e.g. December
mon        Month as locale's abbreviated name, e.g. Dec
mm         2-digit month, e.g. 12
dd         2-digit day of the month, e.g. 22
dow        Day of the week as locale's full name, e.g. Tuesday
doy        Julian day of year starting from 001
hour       2-digit hour, e.g. 10
min        2-digit minute, e.g. 15
sec        2-digit second, e.g. 30
strftime   Apply strftime template to date/time. Should be used in form
           {docx:created.strftime,TEMPLATE} where TEMPLATE is a valid strftime
           template, e.g. {docx:created.strftime,%Y-%U} would result in year-
           week number of year: '2020-23'. If used with no template will return
           null value. See https://strftime.org/ for help on strftime templates.