praat-textgrids -- Praat TextGrid manipulation in Python

Description

textgrids is a module for handling Praat TextGrid files in any format (short text, long text, or binary). The module implements five classes, from largest to smallest:

• TextGrid -- a dict with tier names as keys and Tiers as values
• Tier -- a list of either Interval or Point objects
• Interval -- an object representing Praat intervals
• Point -- a namedtuple representing Praat points
• Transcript -- a str with special methods for transcription handling

All Praat text objects are represented as Transcript objects.

The module also exports the following variables:

• diacritics -- a dict of all diacritics with their Unicode counterparts
• inline_diacritics -- a dict of inline (symbol-like) diacritics
• index_diacritics -- a dict of over/understrike diacritics
• symbols -- a dict of special Praat symbols with their Unicode counterparts
• vowels -- a list of all vowels in either Praat or Unicode notation

And the following constants (although they are not actually constants in Python, they SHOULDN’T be changed):

• BINARY -- symbolic name for the binary file format
• TEXT_LONG -- symbolic name for the long text file format
• TEXT_SHORT -- symbolic name for the short text file format
• version -- module version as string

Version

This file documents praat-textgrids version 1.4.0.

Copyright

Copyright © 2019–24 Legisign.org, Tommi Nieminen [email protected]

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see https://www.gnu.org/licenses/.

Module contents

0. Module properties

Besides textgrids.version, which contains the module version number as string, the module exports the following properties:

0.1. symbols

symbols is a dict that contains all the Praat special notation symbols (as keys) and their Unicode counterparts (as values).

0.2. vowels

vowels is a list of all vowel symbols in either Praat notation (e.g., "\as") or in Unicode. It is used by Interval methods containsvowel() and startswithvowel(), so changing it, for example, adding new symbols to it or removing symbols used for other purposes in a specific case, will change how those methods function.

0.3. diacritics, inline_diacritics, and index_diacritics

diacritics is a dict of all diacritics in Praat notation (as keys) and their Unicode counterparts (as values).

inline_diacritics and index_diacritics are subsets of diacritics. The former are semantically diacritics but appear as inline symbols, the latter are the "true" diacritics (i.e., under- or overstrikes) that need special handling when transcoding.

0.4. TEXT_LONG, TEXT_SHORT, BINARY

Symbolic constants specifying different file formats in TextGrid.format() and TextGrid.write() methods. Internally they are just small integers (0, 1, and 2, respectively). The default format is TEXT_LONG.

1. TextGrid

TextGrid is an collections.OrderedDict whose keys are tier names (strings) and values are Tier objects. The constructor takes an optional filename argument for easy loading and parsing textgrid files.

1.1. Properties

All the properties of dict plus:

• filename holds the textgrid filename, if any. read() and write() methods both set or update it.

1.2. Methods

All the methods of dict plus:

• parse() -- parse string into a TextGrid
• read() -- read (and parse) a TextGrid file
• tier_from_csv() -- read a textgrid tier from a CSV file
• tier_to_csv() -- write a textgrid tier into a CSV file
• write() -- write a TextGrid file

parse() takes an obligatory string (or bytes) argument which contains textgrid data in any of Praat’s three formats (long text, short text, or binary).

read() and write() both take an obligatory filename argument.

write() can take an optional argument specifying the file format; this can be one of BINARY (= int 2), TEXT_LONG (= int 0, the default), or TEXT_SHORT (= int 1).

tier_from_csv() and tier_to_csv() both take two obligatory arguments, the tier name and the filename, in that order.

2. Tier

Tier is a list of either Interval or Point objects.

NOTE: Tier only allows adding Interval or Point objects. Adding anything else or mixing Intervals and Points will trigger an exception.

2.2. Properties

All the properties of list plus:

• is_point_tier -- bool True for point tier, False for interval tier.
• tier_type -- str, either "IntervalTier" or "PointTier"

tier_type exists principally for the convenience of the formatting functions.

2.3. Methods

All the methods of list plus:

• merge() -- merge intervals NOTE renamed from 1.3!
• to_csv() -- convert tier data into a CSV-like list

merge() merges given intervals into one. It takes two arguments, first= and last=, both of which are integer indexes with the usual Python semantics: 0 stands for the first element, -1 for the last element, these being also the defaults. The function raises a TypeError if used with a point tier, and ValueError if the parameters do not specify a valid slice. NB! This is a function and returns the result instead of modifying the Tier in place.

to_csv() returns a CSV-like list. It’s mainly intended to be used from the TextGrid level method tier_to_csv() but can be called directly if writing to a file is not desired.

3. Interval

Interval is an object class representing one Interval on an IntervalTier.

3.1. Properties

• dur -- interval duration (float)
• mid -- interval midpoint (float)
• text -- text label (Transcript)
• xmax -- interval end time (float)
• xmin -- interval start time (float)

3.3. Methods

• containsvowel() -- does the interval contain a vowel?
• endswithvowel() -- does the interval end with a vowel?
• startswithvowel() -- does the interval start with a vowel?
• timegrid() -- create a time grid

containsvowel(), endswithvowel(), and startswithvowel() are bool functions (or predicates, in Lisp-parlance). They check for possible vowels in the text property in both Praat notation and Unicode, but can of course make an error if symbols are used in an unexpected way. They don’t take arguments. (Internally, endswithvowel() first transcodes the text to IPA removing all diacritics to simplify the test.)

timegrid() returns a list of timepoints (in float) evenly distributed from xmin to xmax. It takes an optional integer argument specifying the number of timepoints desired; the default is 3. It raises a ValueError if the argument is not an integer or is less than 1.

4. Point

Point is a namedtuple representing one Point on a PointTier.

4.1. Properties

• text -- text label (Transcript)
• xpos -- temporal position (float)

5. Transcript

Transcript is a str-derived class with one special method: transcode().

5.1. Properties

All the properties of str.

5.2. Methods

All the methods of str plus:

• transcode() -- convert Praat notation to Unicode or vice versa.

Without arguments, transcode() assumes its input to be in Praat notation and converts it to Unicode; no check is made as to whether the input really is in Praat notation but nothing should happen if it isn’t. User should take care and handle any exceptions.

Optional to_unicode=False argument inverts the direction of the transcoding from Unicode to Praat. Again, it is not checked whether input is in Unicode.

With optional retain_diacritics=True argument the transcoding does not remove over- and understrike diacritics from the result.

6. Exceptions

• BinaryError -- invalid or unknown binary file format
• ParseError -- invalid or unknown text file format

Examples

Snippet 1: list syllable durations

import sys
import pathlib
import textgrids

for arg in sys.argv[1:]:
	pathname = pathlib.Path(arg)
	
    try:
        grid = textgrids.TextGrid(pathname)
    except FileNotFoundError:
    	print(f'File not found: {pathname.stem}', file=sys.stderr)
    	continue
    except PermissionError:
    	print(f'Cannot read: {pathname.stem}', file=sys.stderr)
    	continue
    except (textgrids.ParseError, textgrids.BinaryError):
    	print(f'Invalid file format: {pathname.stem}', file=sys.stderr)
    	continue

    # We are only interested in the "syllables" tier
    if 'syllables' not in grid:
    	print(f'No "syllables" grid in: {pathname.stem}', file=sys.stderr)
    	continue
    for syll in grid['syllables']:
        # Convert Praat to Unicode in the label
        label = syll.text.transcode()
        # Print label and syllable duration, CSV-like
        print(f'"{label}";{syll.dur}')

Snippet 2: calculate mean segment duration

import sys
import pathlib
import textgrids

for arg in sys.argv[1:]:
    name = pathlib.Path(arg).stem
    try:
        grid = textgrids.Grid(arg)
    except FileNotFoundError:
        print(f'File not found: "{name}"', file=sys.stderr)
        continue
    except PermissionError:
        print(f'Cannot read: "{name}"', file=sys.stderr)
        continue
    except (textgrids.ParseError, textgrids.BinaryError):
        print(f'Invalid file format: "{name}"', file=sys.stderr)
        continue
    if 'segments' not in grid:
        print(f'No "segments" grid in: "{name}"', file=sys.stderr)
        continue
    # I usually use `#' to caption unclear or otherwise not applicable
    # segments in textgrids; this weeds them out
    segments = [s for s in grid['segments'] if s.text and s.text != '#']
    mean = sum(segm.dur for segm in segments) / len(segments)
    print(f'{name}: mean segment duration = {mean}')

Snippet 3: convert any textgrid to binary format

import sys
import pathlib
import textgrids

for arg in sys.argv[1:]:
    path = pathlib.Path(arg)
    try:
        grid = textgrids.TextGrid(path)
    except (textgrids.ParseError, textgrids.BinaryError):
        print('Not a recognized file format!', file=sys.stderr)
        continue

    # Write a new file
    grid.write(path.with_suffix('.bin'), fmt=textgrids.BINARY)