Fileseq

A Python library for parsing frame ranges and file sequences commonly used in VFX and Animation applications.

Frame Range Shorthand

Support for:

Standard: 1-10
Comma Delimited: 1-10,10-20
Chunked: 1-100x5
Filled: 1-100y5
Staggered: 1-100:3 (1-100x3, 1-100x2, 1-100)
Negative frame numbers: -10-100
Subframes: 1001-1066x0.25, 1001.5-1066.0x0.5
Padding: #=4 padded, @=1 padded
Alternate padding: #=1 padded, @=1 padded
Printf Syntax Padding: %04d=4 padded, %01d=1 padded
Houdini Syntax Padding: $F4=4 padding, $F=1 padded
Udim Syntax Padding: or %(UDIM)d, always 4 padded

FrameSets

A FrameSet wraps a sequence of frames in a list container.

Iterate a FrameSet

fs = fileseq.FrameSet("1-5")
for f in fs:
  print(f)

Access Frames

Using Indices:

>>> fs = fileseq.FrameSet("1-100:8")
>>> fs[0] # First frame.
1
>>> fs[-1] # Last frame.
98

Using Convenience Methods:

>>> fs = fileseq.FrameSet("1-100:8")
>>> fs.start() # First frame.
1
>>> fs.end() # Last frame.
98

FileSequence

Instantiate from String

fileseq.FileSequence("/foo/bar.1-10#.exr")
fileseq.FileSequence("/foo/bar.1-10x0.25#.#.exr", allow_subframes=True)

Format Path for VFX Software

Using FileSequence.format Method:

>>> seq = fileseq.FileSequence("/foo/bar.1-10#.exr")
>>> seq.format(template='{dirname}{basename}{padding}{extension}') 
"/foo/bar.#.exr"
>>> seq = fileseq.FileSequence("/foo/bar.1-10#.#.exr", allow_subframes=True)
>>> seq.format(template='{dirname}{basename}{padding}{extension}')
"/foo/bar.#.#.exr"

Joining:

>>> seq = fileseq.FileSequence("/foo/bar.1-10#.exr")
>>> ''.join([seq.dirname(), seq.basename(), '%0{}d'.format(len(str(seq.end()))), seq.extension()])
"/foo/bar.%02d.exr"

Alternate Padding Styles:

>>> seq = fileseq.FileSequence("/foo/bar.1-10#.exr", pad_style=fileseq.PAD_STYLE_HASH1)
>>> list(seq)
['/foo/bar.1.exr',
 '/foo/bar.2.exr',
 '/foo/bar.3.exr',
 '/foo/bar.4.exr',
 '/foo/bar.5.exr',
 '/foo/bar.6.exr',
 '/foo/bar.7.exr',
 '/foo/bar.8.exr',
 '/foo/bar.9.exr',
 '/foo/bar.10.exr']
>>> seq = fileseq.FileSequence("/foo/bar.1-10#.exr", pad_style=fileseq.PAD_STYLE_HASH4)
>>> list(seq)
['/foo/bar.0001.exr',
 '/foo/bar.0002.exr',
 '/foo/bar.0003.exr',
 '/foo/bar.0004.exr',
 '/foo/bar.0005.exr',
 '/foo/bar.0006.exr',
 '/foo/bar.0007.exr',
 '/foo/bar.0008.exr',
 '/foo/bar.0009.exr',
 '/foo/bar.0010.exr']

Get List of File Paths

>>> seq = fileseq.FileSequence("/foo/bar.1-10#.exr")
>>> [seq[idx] for idx, fr in enumerate(seq.frameSet())]
['/foo/bar.0001.exr',
 '/foo/bar.0002.exr',
 '/foo/bar.0003.exr',
 '/foo/bar.0004.exr',
 '/foo/bar.0005.exr',
 '/foo/bar.0006.exr',
 '/foo/bar.0007.exr',
 '/foo/bar.0008.exr',
 '/foo/bar.0009.exr',
 '/foo/bar.0010.exr']

Get List of File Paths as `pathlib.Path` instances

fileseq.FilePathSequence supports the same semantics as fileseq.FileSequence but represents result paths as pathlib.Path instances instead of strings.

>>> seq = fileseq.FilePathSequence("/foo/bar.1-10#.exr")
>>> [seq[idx] for idx, fr in enumerate(seq.frameSet())]
[PosixPath('/foo/bar.0001.exr'),
 PosixPath('/foo/bar.0002.exr'),
 PosixPath('/foo/bar.0003.exr'),
 PosixPath('/foo/bar.0004.exr'),
 PosixPath('/foo/bar.0005.exr'),
 PosixPath('/foo/bar.0006.exr'),
 PosixPath('/foo/bar.0007.exr'),
 PosixPath('/foo/bar.0008.exr'),
 PosixPath('/foo/bar.0009.exr'),
 PosixPath('/foo/bar.0010.exr')]

Finding Sequences on Disk

Check a Directory for All Existing Sequences

seqs = fileseq.findSequencesOnDisk("/show/shot/renders/bty_foo/v1")

Or, to get results as pathlib.Path, use the FilePathSequence classmethod:

seqs = fileseq.FilePathSequence.findSequencesOnDisk("/show/shot/renders/bty_foo/v1")

Check a Directory for One Existing Sequence.

Use a '@' or '#' where you might expect to use '*' for a wildcard character.
For this method, it doesn't matter how many instances of the padding character you use, it will still find your sequence.

Yes:

fileseq.findSequenceOnDisk('/foo/bar.@.exr')

Yes:

fileseq.findSequenceOnDisk('/foo/bar.@@@@@.exr')

No:

fileseq.findSequenceOnDisk('/foo/bar.*.exr')

To find subframe sequences you must explicitly opt-in

fileseq.findSequenceOnDisk('/foo/bar.#.#.exr', allow_subframes=True)

Development

Getting Started

pip install hatch              # Install build tool
pip install -e ".[dev]"         # Install package with dev dependencies

Running Tests

hatch run test
hatch run test-cov  # with coverage report

Regenerating the Parser

After modifying src/fileseq/grammar/fileseq.g4:

hatch run generate  # Requires Java 11+

Building Documentation

hatch run docs:build
hatch run docs:serve  # View at http://localhost:8000

Limitations

While there may be many custom types of sequence patterns that could be considered a valid pipeline format, this library has taken an opinionated stance on acceptable sequence formats. This is done to keep parsing rules manageable and to not over-complicate the logic. The parsing rules can and have been expanded in some ways over time, such as adding support for new padding format patterns like printf "%04d", houdini "$F" and "<UDIM>". But other rules remain the same, such as expecting a frame number component to be found just before the file extension component.

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