I always use mpv as the default player which use libass to render the subtitle. Usually, any fonts those which are put in the directory of the mpv/fonts/ will be correctly used by libass. However, some fonts whose name's first world is CJK cannot be loaded by libass.

For example, the font 中chinese.tff will not be loaded. But if I change its name to chinese中.tff , everything is OK.

The original issue posted in mpv project. https://github.com/mpv-player/mpv/issues/8639

I am working on Kodi to convert current subtitles rendering to use LibAss here we have an option to force the subtitles to stay positioned e.g. below the video but I don't know how best to manage it with LibAss, i explain,

The subtitles parsers now generate each ASS_Event or if loaded as ASS/SSA use selective style override to change style, currently if a user choose to set subtitles on top or below i change the ASS_Style Alignment property. This works good, but, if a subtitle have overrides tag's like {\a5} etc... of course the subtitle will be moved in the specified position

how i can force to ignore all positions tags like {\a5}? or force in some way the rendering to not change position?

i have tried also ass_set_line_position but is not useful in this case

To resolve #531. In case of non-Unicode cmap fonts, convert unicode code point(a UCS-4 code unit) to corresponding multibyte charset bytes, then assemble those bytes into a uint32_t, assuming those bytes present a prefix-zero-bytes-omitted big-endian integer. Freetype can make use of the converted code point to find correct glyph by non-Unicode cmap.

It introduces a dependency of libiconv. On Windows, WideCharToMultiByte is available to avoid libiconv if needed.

And I have just tested this patch on samples from #531 and #575, which covers BIG5 and SHIFT-JIS. For other encodings, I think it should work but I can't confirm. So further testing is needed.

#531 testing screenshot:

#575 testing screenshot:

I opened this issue in the MPV repo and was told to ask here if anyone knows why this happens.

Using MPV, The line should show up like this:

But the line shows up like this:

Here is a test file: Test.zip

Can anyone help me identify the problem? Thank you.

There's an anime I'm watching with SMPlayer (which is using libass). Now and then (often after the first half of the video) the subtitles are simply gone. However, when I then restart SMPlayer and rewind a bit the subtitles are often displayed correctly.

What information would you need to fix that? (or figure out if it's libass' fault)

This was performed in two steps (commits):

• Separate the non-printable simple-shaper detection into a stand-alone function.
• Reuse this function by the complex shaper.

I don't know if this is a libass issue or mpv issue, but I'd appreciate your help to recognize the source of the issue and/or the best way to address it.

Platform: Windows 10 mpv: master libass: d82f999 (2021-05-01)

Whenever mpv tries to display backslash at the OSD, the backslash IS displayed, but mpv prints a warning.

Steps to reprodue:

• run mpv --no-config --force-window --idle
• press tilde/backtick at the window to open the internal console
• type show-text foo\bar and press enter (the backslash is correctly taken literally - that's how mpv parsing works)

Result: foo\bar is displayed at the OSD, and the terminal displays

[osd/libass] fontselect: failed to find any fallback for font: (sans-serif, 400, 0)

I tried other fonts by adding to the mpv command line e.g. --osd-font=Arial or --osd-font="Comic Sans MS" - with same warning except the different font name at the message (the display font does change visibly).

mpv does escape \ internally by default for any OSD text by appending U+2060 right after it so that libass doesn't recognize it as a begining of an ass sequence, via this code: https://github.com/mpv-player/mpv/blob/dd4d239bcb151b08eb81b38486515a3e1222e1f5/sub/osd_libass.c#L223-L225

If I change 0x2060 (Word Joiner) to 0x200B (Zero Width Space) then it seems to behave the same but without the warning - i.e. this seem to fix the issue.

So I have few questions:

1. It seems to me that libass tries to find the glyph for U+2060 and fails. Is this a correct behavior? Are fonts expected to have a glyph for this codepoint?
2. For escaping \ in strings, which should be more correct to use between U+2060 and U+200B ? (i.e. should we change mpv to use U+200B?)
3. If we do change mpv to use U+200B, could any issue arrise with older versions of libass which would be avoided with U+2060?

Thanks in advance.

• use font->desc.family to search in-memory fonts, otherwise the font will never be found
• pass 0 for face_index to FT_New_Memory_Face, otherwise the call may fail with Invalid Argument error in FreeType

match_fonts is supposed to add all the fonts with the same family name for fontselect. The previous PR adds only one font, which leads to font with multiple styles cannot be correctly selected.

I have had the ASM disabled in the OpenBSD port for quite awhile as I couldn't get it to build. I tried again with 0.15.1, but it is still not building Ok.

I am looking around with libtool trying to figure out where the -fPIC -DPIC was added. It's the -fPIC that is causing the error.

/usr/local/bin/libtool  --tag=CC --mode=compile nasm -DARCH_X86_64=1 -f elf64 -Dprivate_prefix=ass -I./ -o x86/rasterizer.lo x86/rasterizer.asm -prefer-non-pic
libtool: compile:  nasm -DARCH_X86_64=1 -f elf64 -Dprivate_prefix=ass -I./ x86/rasterizer.asm  -fPIC -DPIC -o x86/.libs/rasterizer.o
nasm: fatal: unrecognised output format `PIC' - use -hf for a list
Type nasm -h for help.

hi

using last mpv in windows (with HarfBuzz)

libass

libass with the Pointing

vsfilter

libass

vsfilter

wrong word order because of underline code

video sample http://www.solidfiles.com/d/9287427ae4/[Devil-Fansub]Hyouka-_11.mkv

sub + font http://www.solidfiles.com/d/1c8cb1aace/sub_%2B_font.rar

thanks

Screenshots

This is how it looks in v0.16 with "sub-spacing=0.8"

This is how it looks in v0.16 without "sub-spacing=0.8" (This is how it should look, and it looks like this in previous versions like v0.15.2 with and without sub-spacing)

Description of the issue

Arabic, could be all RTL languages, subtitles render incorrectly as of the latest update 0.16 if "sub-spacing" is used. Downgrading to the previous version 0.15.2 immediately fixed the issue.

The screenshots are taken from MPV.

libass version

0.16.0

Is it a regression?

Recent change, since 0.16.0

ASS Sample

No response

Special Fonts

The issue doesn't depend on a specific font

System Information

OS: (Arch Linux 5.18.3) CPU: (AMD 3600x) GPU: (NVIDIA RTX 2060)

Log

No response

Additional info

No response

Last commit will be dropped before a merge and included in a follow up patch series. It is included as a preview to illustrate how ASS_FUZZMODE or its alternative FUZZ_CPPFLAGS (better matching FUZZ_LDFLAGS) will affect it.

This adds the fuzzer used to find the recently fixed UB, e.g. negative fontsize. Having it in the repo simplifies reproducing the issues for others, allows us to utilise it in ART which will be more efficient than profile and no longer requires the start and end times of samples to be known. It can also be used in OSS-Fuzz, which currently has its own fuzzer source producing suspected bogus memory leaks we couldn't reproduce locally (the version here always fully reinitialises and cleans up the library handles, so this shouldn't happen anymore).

As for the OSS-Fuzz-specific build target, after some experimenting I believe this manual linking is the least ugly way to allow OSS-Fuzz to use the new fuzzer.
Including the link rules here will also enable us to push fixes (like for the memory leaks) or updates if anything about out build changed without having to go through a CLAed PR in OSS-Fuzz’s repo. It certainly isn't ideal to include OSS-Fuzz-specifics into our build system though, so if you don't like it don't hesitate to say so. We could leave the final link command in OSS-Fuzz’s own build rules.

For reference, this is how OSS-Fuzz could be updated to make use of these changes (removal of old fuzzer and dict omitted): ossfuzz-diff.txt

Screenshots

Two sets of screenshots, in order libass and xy-VSFilter

Description of the issue

Such as screenshots, different font display size when use vertical font. Not all fonts have this problem, the most common is Source Han Sans / Serif, some time ago I found that some fonts also have the problems with this, such as FOT-Seurat (I don‘t know can I upload this font, I can upload if needed). As said in https://github.com/libass/libass/issues/600, libass only merely rotates some glyphs.

The problem maybe these fonts have different font height values between horizontal and vertical when use VSFilter, such as if display Source Han Sans in same size, then horizontal font height is 46, vertical font height is 126, so need to adjust the font size to 2.74 times. Thanks to my friend for finding this scale ratio.

In addition, horizontal display also have slightly different.

I don‘t know which display effect is corret, and how will libass handle this incompatibility, match VSFilter or other ways to correctly handle vertical fonts.

libass version

0.15.2

Is it a regression?

No

ASS Sample

[Script Info]
; Script generated by Aegisub 0-dev-72343b7
; http://www.aegisub.org/
Title: Default Aegisub file
ScriptType: v4.00+
WrapStyle: 0
ScaledBorderAndShadow: yes
PlayResX: 1280
PlayResY: 720
YCbCr Matrix: None

[Aegisub Project Garbage]
Video File: ?dummy:23.976000:50000:3840:2160:6:180:231:
Video AR Value: 1.777778
Video Zoom Percent: 0.335185

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,0,2,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\[email protected] ProN B\fs80\shad0\frz270\an7\pos(512.199,326.188)}フォント
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\fnFOT-Seurat ProN B\fs80\shad0\pos(636.519,391.823)}フォント

[Script Info]
; Script generated by Aegisub 0-dev-72343b7
; http://www.aegisub.org/
Title: Default Aegisub file
ScriptType: v4.00+
WrapStyle: 0
ScaledBorderAndShadow: yes
PlayResX: 1280
PlayResY: 720
YCbCr Matrix: None

[Aegisub Project Garbage]
Video File: ?dummy:23.976000:50000:3840:2160:6:180:231:
Video AR Value: 1.777778
Video Zoom Percent: 0.335185
Active Line: 1

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,0,2,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\[email protected] Han Sans JP\fs80\shad0\frz270\an7\pos(512.199,326.188)}フォント
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\fnSource Han Sans JP\fs80\shad0\pos(636.519,391.823)}フォント

Special Fonts

I uploaded or linked to the required font

System Information

No response

Log

No response

Additional info

No response

Screenshots

Only screenshots and sample for negative Fontsizes. @astiob: can you add the "large positive fontsize" sample mentioned on IRC?

xy-VSFilter (xy-VSFilter bundled in Aegisub r8250, Windows 7, 32-bit binary):

libass since #615 (before it crashed)

Description of the issue

For negative fontsizes VSFilter/GDI uses something like the absolute size, but not quite. The rendered size is a bit larger than expected and the difference is larger than just a different rounding direction of the final value. For large positive values apparently something similar happens.

libass version

8e80f49ba70d6f16d8f244a7f41dfeee98d416df

ASS Sample

Font is version 2.37 of DejaVu Sans

[Script Info]
ScriptType: v4.00+
WrapStyle: 0
ScaledBorderAndShadow: yes
YCbCr Matrix: None
PlayResX: 1280
PlayResY: 720

Video File: ?dummy:25.000000:40000:1280:720:47:191:225:
Video AR Value: 1.777778

[Aegisub Project Garbage]
Video File: ?dummy:25.000000:40000:1280:720:47:191:225:
Video AR Value: 1.777778

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: sm48,DejaVu Sans,-48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: sm16,DejaVu Sans,-16,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: sm4,DejaVu Sans,-4,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: sm1,DejaVu Sans,-1,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: Default,DejaVu Sans,100,&H0011FF11,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: s48,DejaVu Sans,48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: s16,DejaVu Sans,16,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: s4,DejaVu Sans,4,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: s1,DejaVu Sans,1,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,2,8,10,10,10,1
Style: bordstyle3,DejaVu Sans,42,&H00EEEEEE,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,3,0,0,8,10,10,10,1
Style: s22,DejaVu Sans,22,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,0,9,10,10,10,1
Style: sm22,DejaVu Sans,-22,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,-1,0,0,0,100,100,0,0,1,4,0,7,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.00,sm48,,0,0,0,,{\an7}A
Dialogue: 0,0:00:00.00,0:00:05.00,sm48,,0,0,0,,{\an7}B
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an7}{\fs-48}D
Dialogue: 0,0:00:00.00,0:00:05.00,sm48,,0,0,0,,{\an7}C
Dialogue: 0,0:00:00.00,0:00:05.00,sm16,,0,0,0,,{\an7}E
Dialogue: 0,0:00:00.00,0:00:05.00,sm16,,0,0,0,,{\an7}F
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an7}{\fs-16}G
Dialogue: 0,0:00:00.00,0:00:05.00,sm16,,0,0,0,,{\an7}H
Dialogue: 0,0:00:00.00,0:00:05.00,sm4,,0,0,0,,{\an7}I
Dialogue: 0,0:00:00.00,0:00:05.00,sm4,,0,0,0,,{\an7}J
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an7}{\fs-4}K
Dialogue: 0,0:00:00.00,0:00:05.00,sm4,,0,0,0,,{\an7}L
Dialogue: 0,0:00:00.00,0:00:05.00,sm1,,0,0,0,,{\an7}M
Dialogue: 0,0:00:00.00,0:00:05.00,sm1,,0,0,0,,{\an7}N
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an7}{\fs-1}O
Dialogue: 0,0:00:00.00,0:00:05.00,sm1,,0,0,0,,{\an7}P

Dialogue: 0,0:00:00.00,0:00:05.00,s48,,0,0,0,,{\an9}A
Dialogue: 0,0:00:00.00,0:00:05.00,s48,,0,0,0,,{\an9}B
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an9}{\fs48}D
Dialogue: 0,0:00:00.00,0:00:05.00,s48,,0,0,0,,{\an9}C
Dialogue: 0,0:00:00.00,0:00:05.00,s16,,0,0,0,,{\an9}E
Dialogue: 0,0:00:00.00,0:00:05.00,s16,,0,0,0,,{\an9}F
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an9}{\fs16}G
Dialogue: 0,0:00:00.00,0:00:05.00,s16,,0,0,0,,{\an9}H
Dialogue: 0,0:00:00.00,0:00:05.00,s4,,0,0,0,,{\an9}I
Dialogue: 0,0:00:00.00,0:00:05.00,s4,,0,0,0,,{\an9}J
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an9}{\fs4}K
Dialogue: 0,0:00:00.00,0:00:05.00,s4,,0,0,0,,{\an9}L
Dialogue: 0,0:00:00.00,0:00:05.00,s1,,0,0,0,,{\an9}M
Dialogue: 0,0:00:00.00,0:00:05.00,s1,,0,0,0,,{\an9}N
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an9}{\fs1}O
Dialogue: 0,0:00:00.00,0:00:05.00,s1,,0,0,0,,{\an9}P

Dialogue: 0,0:00:00.00,0:00:15.00,bordstyle3,,0,0,0,,{\an2}Borderstyle=3 Outline=0{test if classic/xy VSF or MPC-HC ISR?}

Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,Style Neg:
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs-36}W{ 57.2}
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs-22}W{ 26.4}
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs-11}W{  2.2}
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,W
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs+11}W{ -46.2}
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs+22}W{ -70.4}
Dialogue: 0,0:00:05.01,0:00:10.00,sm22,,0,0,0,,{\fs+36}W{ -101.2}

Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\an9}Style Pos:
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs-36}W{ -57.2}
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs-22}W{ -26.4}
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs-11}W{  -2.2}
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,W
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs+11}W{ -46.2}
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs+22}W{ -70.4}
Dialogue: 0,0:00:05.01,0:00:10.00,s22,,0,0,0,,{\fs+36}W{ 101.2}

Special Fonts

I uploaded or linked to the required font

System Information

Native CPU-Arch: x86_64 VSFilter System: Windows 7, Aegisub+VSFilter 32-bit binary libass System: glibc-Linux with freetype 2.10.4, fontconfig 2.13.1

Screenshots

While I can't find a way to test this against VSFilter, I was told to file an issue, and this seemed like the most appropriate category.

Description of the issue

Drawings require their style- or \fn-specified font to be found to render. When running mpv with --sub-font-provider=none, drawings will (apparently) fail to fallback to any font if the specified one isn't muxed, and fail to render anything.

Example where this could come up: Typesetting done with a style defaulting to Arial, but Arial itself is not muxed in, as it's not actually used in any events (Aegisub's font collector, for instance, will not grab it in this case). Users who don't have Arial installed (or at least, those who have neither Arial nor any other font libass would fall back on in this case) will not see the drawings.

In addition, I get the following error in the latter (failing) case:

   sub/ass: fontselect: failed to find any fallback with glyph 0x0 for font: (Arial, 400, 0)

libass version

osd/libass: libass source: commit: ac2ddef8841aa2ff37ca9b83f19f15092d0cacc6

Is it a regression?

As far as I am aware, this has always been the case.

ASS Sample

Full ASS file used: font-drawing-rendering.ass.txt

[Script Info]
; Script generated by Aegisub 9215, Daydream Cafe Edition [Shinon]
; http://www.aegisub.org/
Title: Default Aegisub file
ScriptType: v4.00+
WrapStyle: 0
ScaledBorderAndShadow: yes
YCbCr Matrix: None
PlayResX: 1280
PlayResY: 720

[V4+ Styles]
Format: Name, Fontname, Fontsize, PrimaryColour, SecondaryColour, OutlineColour, BackColour, Bold, Italic, Underline, StrikeOut, ScaleX, ScaleY, Spacing, Angle, BorderStyle, Outline, Shadow, Alignment, MarginL, MarginR, MarginV, Encoding
Style: Default,Arial,48,&H00FFFFFF,&H000000FF,&H00000000,&H00000000,0,0,0,0,100,100,0,0,1,2,2,2,10,10,10,1

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 0,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\an5\bord0\shad0\blur1\p1\fscx535\fscy198\pos(644,338)\c&H0000FF&}m 0 0 l 100 0 100 100 0 100
Dialogue: 1,0:00:00.00,0:00:05.00,Default,,0,0,0,,{\pos(644,382)\fnGandhi Sans\b1}SHOULD HAVE RED\N BACKGROUND MASK

Special Fonts

The issue doesn't depend on a specific font. The sample uses Gandhi Sans Bold, which can be found for free, for instance at https://www.fontsquirrel.com/fonts/gandhi-sans.

System Information

OS: Windows 11

Log

Full logs: font-drawing-rendering.log

Additional info

I can also upload the entire mkv file (it's just 5 seconds of 1280x720 black screen, the above ASS file, and Gandhi Sans), if this helps.

Screenshots

It is useless in this case.

Description of the issue

libass does not respect vsfilter font used. Like you can see in the Additional info section, I give what I write in the \b tags and which font is been displayed.

I test it with AegisubDC 9214 and I use subtitle provider vsfiltermod_textsub and of course, libass.

Of course, this is only an example. VSFilter does maybe some other choice when x font weight is not installed. In my example, all the possible font weight are available.

libass version

AegisubDC 9214

Is it a regression?

I don't know

ASS Sample

See the MODDED_FONT.zip file

Special Fonts

Here are the modded font I used and the .ass: MODDED FONT.zip

System Information

OS: Windows 10 CPU: i5-7600

Additional info

VSFilter

\bVALUE --> FONT_WEIGHT

b0 --> 400 b1 --> 700 b2-b99 --> 400 b100-b149 --> 100 b251-b258 --> 100 b150-b250 --> 200 b351-b358 --> 200 b259-b349 --> 300 b451-b461 --> 300 b350 --> 400 b359-b450 --> 400 b551-b561 --> 400 b462-b550 --> 500 b551-b661 --> 500 b562-b650 --> 600 b751-b758 --> 600 b662-b749 --> 700 b750 --> 800 b759-b850 --> 800 b951-b1050 --> 800 b851-b950 --> 900 b1051-infinite --> 900

libass

\bVALUE --> FONT_WEIGHT

b0 --> 400 b1 --> 700 b2 à b99 --> 400 b100-b149 --> 100 b150-b250 --> 200 b251-b349 --> 300 b350-b450 --> 400 b451-b550 --> 500 b551-b650 --> 600 b651-b749 --> 700 b750-b850 --> 800 b851-infinite --> 900