Skip to main content

A library for parsing and manipulating Advanced SubStation Alpha subtitle files.

Project description


A library for parsing and manipulating Advanced SubStation Alpha subtitle files.


Example file: tests/test.ass

You can parse the file:

>>> import ass
>>> with open("tests/test.ass", encoding='utf_8_sig') as f:
...     doc = ass.parse(f)

Access its meta info:

ScriptInfoSection('Script Info', OrderedDict([('ScriptType', 'v4.00+'), ('PlayResX', 500), ('PlayResY', 500)]))

Access its styles:

>>> doc.styles
StylesSection('V4+ Styles', [Style(name='Default', fontname='Arial', fontsize=20.0, primary_color=Color(r=0xff, g=0xff, b=0xff, a=0x00), secondary_color=Color(r=0xff, g=0x00, b=0x00, a=0x00), outline_color=Color(r=0x00, g=0x00, b=0x00, a=0x00), back_color=Color(r=0x00, g=0x00, b=0x00, a=0x00), bold=False, italic=False, underline=False, strike_out=False, scale_x=100.0, scale_y=100.0, spacing=0.0, angle=0.0, border_style=1, outline=1.0, shadow=2.0, alignment=5, margin_l=10, margin_r=10, margin_v=10, encoding=1)])
>>> doc.styles[0].fontname
>>> doc.styles[0].primary_color  # "color", not "colour"
Color(r=0xff, g=0xff, b=0xff, a=0x00)

Access its event lines:

EventsSection('Events', [Dialogue(layer=0, start=datetime.timedelta(0), end=datetime.timedelta(seconds=5), style='Default', name='', margin_l=0, margin_r=0, margin_v=0, effect='', text='{\\3c&H0000FF}this is a test\\N{\\3c&H00FF00}this is a test\\N{\\3c&HFF0000}this is a test'), ...])
'{\\3c&H0000FF}this is a test\\N{\\3c&H00FF00}this is a test\\N{\\3c&HFF0000}this is a test'

Or any other section data:

>>> list(doc.sections.keys())
['Script Info', 'Aegisub Project Garbage', 'Custom Section', 'V4+ Styles', 'Events', 'Aegisub Extradata']
>>> doc.sections['Aegisub Project Garbage']['Scroll Position']

You can dump everything out into ASS format, too:

'0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\\3c&H0000FF}this is a test\\N{\\3c&H00FF00}this is a test\\N{\\3c&HFF0000}this is a test'

Or maybe the whole file:

>>> with open("out.ass", "w", encoding='utf_8_sig') as f:
...     doc.dump_file(f)


For parsing ASS tags, you may want to consider ass-tag-parser: (on GitHub).


The following has been unmaintained for years.

python-ass can use libass for rendering.

First you need to allocate a libass context:

>>> ctx = ass.renderer.Context()

Then you need to convert the ass.document.Document to a ass.renderer.Track:

>>> t = ctx.make_track()
>>> t.populate(doc)

Then make a renderer to render the track:

>>> r = ctx.make_renderer()
>>> r.set_fonts(fontconfig_config="/usr/local/etc/fonts/fonts.conf")
>>> r.set_all_sizes((1280, 720))

You can render a frame at a given time:

>>> imgs = r.render_frame(t, timedelta(0))

Example using PIL to render to a bitmap:

>>> im_out ="RGB", (1280, 720))
>>> im_data = im_out.load()
>>> for img in imgs:
...     r, g, b, a = img.rgba
...     for y in range(img.h):
...         for x in range(img.w):
...             a_src = img[x, y] * (256 - a) // 256
...             r_dst, g_dst, b_dst = im_data[x + img.dst_x, y + img.dst_y]
...             r_out = ((r * a_src) + (r_dst * (256 - a_src))) // 256
...             g_out = ((g * a_src) + (g_dst * (256 - a_src))) // 256
...             b_out = ((b * a_src) + (b_dst * (256 - a_src))) // 256
...             im_data[x + img.dst_x, y + img.dst_y] = (r_out, g_out, b_out)

Sample Rendering (from

Test rendering

Project details

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Files for ass, version 0.5.2
Filename, size File type Python version Upload date Hashes
Filename, size ass-0.5.2-py3-none-any.whl (15.2 kB) File type Wheel Python version py3 Upload date Hashes View
Filename, size ass-0.5.2.tar.gz (15.1 kB) File type Source Python version None Upload date Hashes View

Supported by

AWS AWS Cloud computing Datadog Datadog Monitoring DigiCert DigiCert EV certificate Facebook / Instagram Facebook / Instagram PSF Sponsor Fastly Fastly CDN Google Google Object Storage and Download Analytics Pingdom Pingdom Monitoring Salesforce Salesforce PSF Sponsor Sentry Sentry Error logging StatusPage StatusPage Status page