AssRender is an AviSynth plugin that renders ASS/SSA and SRT (without the HTML-like markup) subtitles. It uses libass to render the subtitles, which makes it the fastest and most correct ASS renderer for AviSynth.

This also means that it is much more picky about script syntax than VSFilter and friends, so keep that in mind before blaming the filter. Yes, people have reported a lot of errors that were actually the script author’s fault.

Usage

assrender(clip, string file, [string vfr, int hinting, float scale, float line_spacing, float dar, float sar, int top, int bottom, int left, int right, string charset, int debuglevel, string fontdir, string srt_font, string colorspace])

string file

Your subtitle file. May be ASS, SSA or SRT.

string vfr

Specify timecodes v1 or v2 file when working with VFRaC.

int hinting

Font hinting mode. Choose between none (0, default), light (1), normal (2) and Freetype native (3) autohinting.

float scale

Font scale. Defaults to 1.0.

float line_spacing

Line spacing in pixels. Defaults to 1.0 and won’t be scaled with frame size.

float dar, float sar

Aspect ratio. Of course you need to set both parameters.

int top, int bottom, int left, int right

Margins. They will be added to the frame size and may be negative.

string charset

Character set to use, in GNU iconv or enca format. Defaults to UTF-8. Example enca format: enca:pl:cp1250 (guess the encoding for Polish, fall back on cp1250)

int debuglevel

How much crap assrender is supposed to spam to stderr.

string fontdir

Additional font directory. Useful if you are lazy but want to keep your system fonts clean.

string srt_font

Font to use for SRT subtitles. Defaults to whatever Fontconfig chooses for “sans-serif”.

string colorspace

The color space of your (YUV) video. Possible values:

• Rec2020, BT.2020
• Rec709, BT.709
• Rec601, BT.601

Default is to use the ASS script’s "YCbCr Matrix:" or "Video Colorspace" property, else guess based on video resolution (width > 1920 or height > 1080 → BT.2020, then width > 1280 or height > 576 → BT.709). Recognized .ASS properties: "tv.601" "tv.709". Other values like "pc.601" "pc.709" "tv.240m" "pc.240m" "tv.fcc" "pc.fcc" are treated as 'guess'.

Build instructions

Windows Visual Studio 2019

• Clone repo

  Clone https://github.com/pinterf/assrender from IDE or

  git clone https://github.com/pinterf/assrender
  git submodule update --init --recursive --remote
  

  Prequisite: vsyasm integration

  • get VSYASM from https://github.com/ShiftMediaProject/VSYASM
  • run install_script.bat

  Prequisite: avisynth.lib versions

  • find in Avisynth+ C API installation
  • copy them to repo_dir\lib\x86-64\ and repo_dir\lib\x86-32
    32 and 64 bit versions respectively

• Build: Open solution file from IDE

Windows GCC (mingw installed by msys2)

Prequisite: avisynth.lib versions

• find in Avisynth+ C API installation
• copy them to repo_dir\lib\x86-64\ and repo_dir\lib\x86-32
  32 and 64 bit versions respectively

Prequisite: libass package (see below)

• Libass package (if not exists)

  List libass versions

  $ pacman -Ss libass
  
  mingw32/mingw-w64-i686-libass 0.15.0-1
    A portable library for SSA/ASS subtitles rendering (mingw-w64)
  mingw64/mingw-w64-x86_64-libass 0.15.0-1
    A portable library for SSA/ASS subtitles rendering (mingw-w64)
  

  Get

  for x64 version:

  $ pacman -S mingw64/mingw-w64-x86_64-libass
  
  resolving dependencies...
  looking for conflicting packages...
  warning: dependency cycle detected:
  warning: mingw-w64-x86_64-harfbuzz will be installed before its mingw-w64-x86_64-freetype dependency
  
  Packages (10) mingw-w64-x86_64-fontconfig-2.13.93-1
              mingw-w64-x86_64-freetype-2.10.4-1
              mingw-w64-x86_64-fribidi-1.0.10-2
              mingw-w64-x86_64-glib2-2.66.4-1
              mingw-w64-x86_64-graphite2-1.3.14-2
              mingw-w64-x86_64-harfbuzz-2.7.4-1
              mingw-w64-x86_64-libpng-1.6.37-3  mingw-w64-x86_64-pcre-8.44-2
              mingw-w64-x86_64-wineditline-2.205-3
              mingw-w64-x86_64-libass-0.15.0-1
  
  Total Download Size:    6.92 MiB
  Total Installed Size:  42.31 MiB
  
  :: Proceed with installation? [Y/n]
  

  Choose Y and wait

• Clone repo

  git clone https://github.com/pinterf/assrender
  

  NOT needed (we have libass as package): git submodule update --init --recursive --remote

• Build from the 'build' folder under project root:

  del ..\CMakeCache.txt
  cmake .. -G "MinGW Makefiles"
  cmake --build . --config Release --clean-first 
  

Linux

• Clone repo

  git clone https://github.com/pinterf/assrender
  NOT needed: git submodule update --init --recursive --remote
  cd assrender
  cmake -B build -S .
  cmake --build build --clean-first
  

• Find binaries at

  build/assrender/libassrender.so
  

• Install binaries

  cd build
  sudo make install
  

Licenses

For all modules: see msvc/licenses

Links

• Doom9 forum: https://forum.doom9.org/showthread.php?t=148926
• Avisynth wiki: http://avisynth.nl/index.php/AssRender

Change log

0.34 (20210301 - pinterf)

• Fix the fix: revert matrix change made in 0.33
• Fix: Check matrix from .ASS file "YCbCr Matrix:" section besides "Video Colorspace:" Recognized values are "tv.601" and "tv.709"

0.33 (20210228 - pinterf)

• Fix: wrong Bt.709 matrix

0.32 (20210227 - pinterf)

• Fix: treat I420 variant as YV12 instead of unsupported color space

0.31 (20210218 - pinterf)

• Fix colors for planar RGB
• code: hidden ifdef FOR_AVISYNTH_26_ONLY for Avisynth 2.6-only build

0.30 (20210217 - pinterf)

• From now assrender does not works with classic Aviysnth: high-bitdepth helper function calls
• 10-16 bit support (including RGB48 and RGB64)
• YV411, Planar RGB support

0.29 (20210216 - pinterf)

• project moved to https://github.com/pinterf/assrender from https://github.com/vadosnaprimer/assrender
• Move to Visual Studio 2019 - v142 platform toolset
• Add .def module definition file for Avisynth 2.6 std compatibility (function name mangling)
• Update Avisynth C headers
• Check Linux and gcc-MinGW CMake build
• Add build instructions and change log to README

no version (20190114 - vadosnaprimer)

• https://github.com/vadosnaprimer/assrender/
• add batch that lets not to change deps sdk and vs version copied from SMP libass
• update SMP submodules

no version (20161018 - Blitzker)

• https://github.com/Blitzker/assrender
• Visual Studio 2015 support

0.28 (20120226 - pingplug)

• small changes and update version to 0.28

0.27 (20150202 - pingplug)

• https://github.com/pingplug/assrender
• add a simple .rc file :-)
• cache the last img to rend faster if img not changed
• add YUY2 and YV16 support

0.25 (20120420 - lachs0r)

• moved to github
• code restructured
• added support for the BT.709 color space and the 'Video Colorspace' property that has been introduced with recent versions of Aegisub.
• binary:
  • updated everything, switched to MinGW-w64 (same toolchain as mplayer2 now)

0.24.1 (20110922 - lachs0r)

• binary changes only
• binary:
  • updated libass to current git HEAD
  • switched Harfbuzz to libass’ compatibility branch
  • compiled Harfbuzz without Uniscribe backend
• fixes lots of crashes and misbehavior

0.24 (20110729)

• fixing the performance regression

0.23 (20110728)

• disabled font hinting by default
• binary:

• updated libass to current git HEAD and included Harfbuzz:
• added support for bidirectional text, Arabic shaping etc.
• added proper support for @fonts (vertical writing)
• slight performance regression (glyph cache not hooked up with Harfbuzz yet)
• updated FreeType to current git HEAD:
• fixed outline stroker for some broken fonts

0.22 (20110618 - lachs0r)

• fixed that annoying hang on vector clips

0.21 (20110608 - lachs0r lachs0r@srsfckn.biz)

• fixed YV12 subsampling so it no longer looks horrible, which should be rather good news for most users.
• temporarily removed YV16 support
• renamed parameter verbosity → debuglevel
• code cleanups
• binary:
  • reverted to GCC 4.5.2 (4.6 miscompiles MinGW)

0.20 (20110601)

• fixed RGB32 support (it’s actually usable with BlankClip(pixel_type="RGB32") now).
• fixed the masksub stuff
• properly output debug messages to stderr instead of stdout
• reformatted source and corrected/removed some comments
• modified CMakeLists.txt to strip the binary by default
• binary:
  • now built with GCC 4.6 instead of 4.5.2
  • included enca again
  • patched fontconfig:
    • prettier debug output
    • use the correct location for its cache

0.19 (2011-02-01 - lachs0r)

This is a bugfix/cleanup release.

• fixed possible buffer overflows in timecodesv1 and SRT parsing
• fixed random crashes on unloading
• probably fixed compilation with MSVC (patch by TheFluff)
• very slightly improved performance with GCC
• various code cleanups

0.16 (2011-01-25 - lachs0r)

• improved YV12 support (should be somewhat usable now)
• added support for RGB24, YV24, YV16 and Y8 (YUY2 coming soon)
• added SRT subtitle format support, additional parameter: srt_font (font to use for srt subs)
• exposed some libass parameters:
  • line_spacing (line spacing)
  • dar, sar (aspect ratio)
  • top, bottom, left, right (margins)
  • fontdir (additional font directory)
• masksub equivalent if used on a blankclip (still buggy - read source for details)
• no more global variables

0.16 (2011-01-17 - lachs0r

• added rudimentary YV12 support (chroma subsampling still needs work)
• binary: Previously, I linked against a very old avisynth_c.lib now you shouldn’t get any error messages about "avisynth_c.dll"
• tidied up the RGB32 blitter a bit

0.16 (2011-01-16)

• implemented VFRaC support via timecodes files (v1 and v2 supported)

0.15 (2011-01-16 - lachs0r)

• reimplemented as AviSynth C plugin - this fixed several crashes and got rid of the major pain in the ass that is MSVC
• binary: built with patched Fontconfig (no longer needs fonts.conf)

0.11 TheFluff

• Source code (under MIT license, binaries are under GPL for obvious reasons): assrender_0.11-src.7z