ASS font audit
Check required fonts and compare same-name ASS styles field by field across local files. Inspect duplicate definitions and missing references without automatic edits.
Audit results
Enter the source, then select Audit used fonts.
A name match does not guarantee installation, full character coverage, weight, italics or video rendering.
Save audit report as TXTCompare styles across ASS files
Compare definitions sharing a style name before merging. No source is changed or merged.
Style comparison results
Compare style collisions to see differences by file.
What style comparison checks
Format columns are matched by name even when reordered. Numeric fields are also compared without leading 0 digits or redundant decimal 0 digits; base-16 colors ignore case and leading 0 digits. Font names and unknown fields only lose surrounding whitespace. Raw values remain visible.
In the public examples, Default has conflicting Fontsize values of 24 and 28. Aside uses 18 versus 018.0 and different color spelling, with equal comparison values. Duplicate definitions within a file and undefined references are listed separately.
Equal definitions do not prove identical rendering. Resolution, script settings, inline overrides and renderer differences are not compared. This is not a numeric-range check or a complete ASS validator.
How the ASS font audit works
Reads Fontname in V4+ styles and \fn/\r tags in dialogue. It distinguishes fonts used by text from unused styles. Drawing-command segments do not count as font usage.
Reads family name and typographic family name from selected TTF/OTF files and compares without case sensitivity. It does not scan installed fonts, download fonts or extract ASS attachments.
The public example uses three fonts: Example Sans, Example Mono and Example Serif. Inspect the usage list without selecting a font file, or select files to compare their family names. In the public examples, Default has conflicting Fontsize values of 24 and 28. Aside uses 18 versus 018.0 and different color spelling, with equal comparison values. Duplicate definitions within a file and undefined references are listed separately.
Supports UTF-8 V4+ ASS, up to 500 styles and 500 used fonts. Missing styles and malformed font tags cause errors. Font changes inside transform animations are unsupported. This is not a full ASS syntax checker or player.
Frequently Asked Questions
Does a missing match mean the font is absent from my computer?
No. It means no family name matched in the TTF/OTF files you selected. Installed fonts are not scanned, and filenames are not used as font identities.
Does a matching name guarantee correct video rendering?
No. Character coverage, weight, italics, player fallback fonts and rendering differences are not checked. Verify actual playback separately.
Which ASS and font files are supported?
The audit reads styles, dialogue and fn/r tags in UTF-8 V4+ ASS. It reads standard TTF/OTF naming tables. TTC/WOFF, embedded font extraction and installed-font discovery are unsupported.
What style comparison checks
Format columns are matched by name even when reordered. Numeric fields are also compared without leading 0 digits or redundant decimal 0 digits; base-16 colors ignore case and leading 0 digits. Font names and unknown fields only lose surrounding whitespace. Raw values remain visible. Equal definitions do not prove identical rendering. Resolution, script settings, inline overrides and renderer differences are not compared. This is not a numeric-range check or a complete ASS validator. 2–8 UTF-8 V4+ ASS files. Per file: 2MiB, 1 million characters, 500 styles and 10000 dialogues. Total: 8MiB, 2 million characters, 2000 styles, 20000 dialogues and 40000 references. Up to 32 fields and 256 characters per field value. Only numeric and base-16 color spelling is normalized. Case and Unicode differences in names are preserved. Style resets inside transform tags are unsupported.
Calculation criteria and reference materials
- Aegisub — ASS font and style tags
Official documentation for fn font changes, r style resets and drawing mode. This tool audits font dependencies; it does not implement ASS playback.
- Microsoft — OpenType naming table
Defines family name ID 1 and typographic family name ID 16 used for comparison. A name match does not establish character coverage or successful rendering.
Verification of calculation criteria: · Calculation·verification principles · Report errors