The results that applied blur are different. <composited video(ffmpeg) vs browser(jassub)>

[lowkey-heonyoung]

I've set blur to 3 to 어때요 text, then do composite video through ffmpeg library with ASS subtitle data. However, the result is different than I expected like below. Especially, when I set the blur, the result has an issue. I'll appreciate it if someone could help me.

composited video(ffmpeg)	browser(jassub)

[Script Info]
ScriptType: v4.00+
PlayResX: 384
PlayResY: 288
ScaledBorderAndShadow: yes
YCbCr Matrix: None
WrapStyle: 0
Collisions: Reverse

[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: Title,Pretendard ExtraBold,28,&H00ffffff,&H00ffffff,&H00000000,&H00000000,0,0,0,0,100,100,,,1,0.5,1.0,2,10,10,161,
Style: Title-box,Pretendard ExtraBold,28,&H00000000,&H00000000,&H00000000,&Hff000000,0,0,0,0,100,100,,,3,1.0,,2,10,10,161,
Style: Subtitle,KOTRA HOPE,44,&H001c1cd3,&H00ffffff,&H00000000,&Hf0000000,0,0,0,0,100,100,,,1,1.0,1.0,2,10,10,77,
Style: Custom1,NanumSquare Neo ExtraBold,44,&H001c1cd3,&H00ffffff,&H00000000,&H0022f6ff,0,0,0,0,100,100,,,1,2.0,2.4,2,10,10,77,
Style: Custom2,NanumSquare Neo ExtraBold,22,&H001c1cd3,&H00ffffff,&H00000000,&Hf0000000,0,0,0,0,100,100,,,1,1.0,1.0,2,10,10,77,

[Events]
Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
Dialogue: 11,0:04:27.00,0:04:30.00,Title,,0,0,0,,{\blur6}자 오늘 주제는 뭐죠?
Dialogue: 10,0:04:27.00,0:04:30.00,Title-box,,0,0,0,,자 오늘 주제는 뭐죠?
Dialogue: 1,0:04:27.18,0:04:28.20,Subtitle,,0,0,0,,{\rCustom2}아니{\r} {\rCustom1}{\blur3}어때요?{\r}

[ThaUnknown]

if you're using dropAllBlur, disable it, if not ask libass, this is merely a wrapper for libass, it doesn't perform any of the rasterization

[lowkey-heonyoung]

@ThaUnknown Thanks a lot for your advice. I'll contact to libass.

[lowkey-heonyoung]

@ThaUnknown Hi, I've received an answer on this issue from libass that it can be related to not calling ass_set_storage_size. Could you take a look of this?

Looks like jassub isn't calling ass_set_storage_size. Blur has this kind of scaling behavior when that isn't called; this is expected. Please report downstream. https://github.com/libass/libass/issues/810#issuecomment-2262276155

[ThaUnknown]

this is possible, i'll debug this sometime this month

[ThaUnknown]

@lowkey-heonyoung you can try the version provided in the git commit artifacts on the latest commit, I haven't published it on NPM yet

[lowkey-heonyoung]

@ThaUnknown I've tried to build the latest commit, but it's quite hard to build.. Can you share the build result so that I can try in the local environment?

[ThaUnknown]

as I said it's in the commit build artifacts

[ThaUnknown]

https://github.com/ThaUnknown/jassub/actions/runs/10255187904

[lowkey-heonyoung]

@ThaUnknown The blur is showing appropriately when running the new version you shared. Thanks a lot.

[ThaUnknown]

published as 1.7.17