feat: LINE Seed font, wording fix, trademark notice

Dockerfile

@@ -26,6 +26,7 @@ COPY frontend/ frontend/
 RUN cd frontend && pnpm install --frozen-lockfile && pnpm build
 
 # Copy source
+COPY assets/ assets/
 COPY src/ src/
 
 EXPOSE 7860

NOTICE

@@ -0,0 +1,25 @@
+BilingualSub
+Copyright 2024-2026 Maple (mapleee723@gmail.com)
+
+Licensed under the Apache License, Version 2.0.
+
+== Trademark Notice ==
+
+"BilingualSub" is the product name of this project. Per Section 6 of the
+Apache License 2.0, this license does not grant permission to use the trade
+names, trademarks, service marks, or product names of the Licensor, except
+as required for reasonable and customary use in describing the origin of the
+Work.
+
+If you create a modified version of this software, you must not distribute
+it under the name "BilingualSub" without explicit written permission from
+the copyright holder. This includes, but is not limited to, the product
+name displayed in video intros, watermarks, and user interfaces.
+
+== Third-Party Fonts ==
+
+This project bundles font files under the SIL Open Font License, Version 1.1.
+See assets/fonts/LICENSE for details.
+
+- LINE Seed Sans: Copyright (c) 2022 LINE Corporation
+- Noto Sans TC: Copyright (c) 2012-2024 Google LLC

assets/fonts/LICENSE

@@ -0,0 +1,98 @@
+The font files in this directory are distributed under the SIL Open Font License, Version 1.1.
+
+=== LINE Seed Sans ===
+
+Copyright (c) 2022 LINE Corporation
+Licensed under the SIL Open Font License, Version 1.1.
+https://github.com/line/seed
+
+=== Noto Sans TC ===
+
+Copyright (c) 2012-2024 Google LLC
+Licensed under the SIL Open Font License, Version 1.1.
+https://github.com/notofonts/noto-fonts
+
+=== SIL Open Font License, Version 1.1 ===
+
+PREAMBLE
+The goals of the Open Font License (OFL) are to stimulate worldwide
+development of collaborative font projects, to support the font creation
+efforts of academic and linguistic communities, and to provide a free and
+open framework in which fonts may be shared and improved in partnership
+with others.
+
+The OFL allows the licensed fonts to be used, studied, modified and
+redistributed freely as long as they are not sold by themselves. The
+fonts, including any derivative works, can be bundled, embedded,
+redistributed and/or sold with any software provided that any reserved
+names are not used by derivative works. The fonts and derivatives,
+however, cannot be released under any other type of license. The
+requirement for fonts to remain under this license does not apply to
+any document created using the fonts or their derivatives.
+
+DEFINITIONS
+"Font Software" refers to the set of files released by the Copyright
+Holder(s) under this license and clearly marked as such. This may
+include source files, build scripts and documentation.
+
+"Reserved Font Name" refers to any names specified as such after the
+copyright statement(s).
+
+"Original Version" refers to the collection of Font Software components as
+distributed by the Copyright Holder(s).
+
+"Modified Version" refers to any derivative made by adding to, deleting,
+or substituting -- in part or in whole -- any of the components of the
+Original Version, by changing formats or by porting the Font Software to a
+new environment.
+
+"Author" refers to any designer, engineer, programmer, technical
+writer or other person who contributed to the Font Software.
+
+PERMISSION & CONDITIONS
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of the Font Software, to use, study, copy, merge, embed, modify,
+redistribute, and sell modified and unmodified copies of the Font
+Software, subject to the following conditions:
+
+1) Neither the Font Software nor any of its individual components,
+in Original or Modified Versions, may be sold by itself.
+
+2) Original or Modified Versions of the Font Software may be bundled,
+redistributed and/or sold with any software, provided that each copy
+contains the above copyright notice and this license. These can be
+included either as stand-alone text files, human-readable headers or
+in the appropriate machine-readable metadata fields within text or
+binary files as long as those fields can be easily viewed by the user.
+
+3) No Modified Version of the Font Software may use the Reserved Font
+Name(s) unless explicit written permission is granted by the corresponding
+Copyright Holder. This restriction only applies to the primary font name as
+presented to the users.
+
+4) The name(s) of the Copyright Holder(s) or the Author(s) of the Font
+Software shall not be used to promote, endorse or advertise any
+Modified Version, except to acknowledge the contribution(s) of the
+Copyright Holder(s) and the Author(s) or with their explicit written
+permission.
+
+5) The Font Software, modified or unmodified, in part or in whole,
+must be distributed entirely under this license, and must not be
+distributed under any other license. The requirement for fonts to
+remain under this license does not apply to any document created
+using the Font Software.
+
+TERMINATION
+This license becomes null and void if any of the above conditions are
+not met.
+
+DISCLAIMER
+THE FONT SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT
+OF COPYRIGHT, PATENT, TRADEMARK, OR OTHER RIGHT. IN NO EVENT SHALL THE
+COPYRIGHT HOLDER BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+INCLUDING ANY GENERAL, SPECIAL, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL
+DAMAGES, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF THE USE OR INABILITY TO USE THE FONT SOFTWARE OR FROM
+OTHER DEALINGS IN THE FONT SOFTWARE.

src/bilingualsub/utils/ffmpeg.py

@@ -10,6 +10,30 @@
 
 import ffmpeg
 
+# ---------------------------------------------------------------------------
+# Bundled font paths — assets/fonts/ next to the project root
+# ---------------------------------------------------------------------------
+
+_ASSETS_DIR = Path(__file__).resolve().parent.parent.parent.parent / "assets" / "fonts"
+_FONT_EN_REGULAR = _ASSETS_DIR / "LINESeedSans_Rg.ttf"
+_FONT_EN_BOLD = _ASSETS_DIR / "LINESeedSans_Bd.ttf"
+_FONT_ZH_REGULAR = _ASSETS_DIR / "NotoSansTC-Regular.ttf"
+_FONT_ZH_BOLD = _ASSETS_DIR / "NotoSansTC-Bold.ttf"
+
+
+def _font_arg(fontfile: Path, fallback_name: str) -> str:
+    """Return a drawtext font option.
+
+    Uses ``fontfile='<path>'`` when the bundled file exists, otherwise falls
+    back to ``font='<name>'`` so the filter chain still works without the
+    assets directory (e.g. inside Docker where system fonts are available).
+    """
+    if fontfile.exists():
+        # fontfile= needs an absolute path; resolve() guarantees that.
+        escaped = str(fontfile.resolve()).replace("'", "'").replace(":", r"\:")
+        return f"fontfile='{escaped}'"
+    return f"font='{fallback_name}'"
+
 
 class FFmpegError(Exception):
     """Exception raised when FFmpeg operations fail."""
@@ -96,7 +120,7 @@ def _append_watermark_drawtext(vf_filter: str, watermark_text: str) -> str:
     safe_text = _escape_drawtext(watermark_text)
     watermark_drawtext = (
         f"drawtext=text='{safe_text}'"
-        ":font='Arial'"
+        f":{_font_arg(_FONT_EN_REGULAR, 'Arial')}"
         ":fontsize=16"
         ":fontcolor=white@0.6"
         ":shadowcolor=black@0.8"
@@ -492,19 +516,24 @@ def _block_enable(start: float) -> str:
 
     def _dt(
         text: str,
-        font: str,
+        font_spec: str,
         fontsize: int,
         fontcolor: str,
         x: str,
         y: str,
         enable_expr: str,
         fade_start: float,
     ) -> str:
+        """Build a drawtext filter block.
+
+        ``font_spec`` is the output of ``_font_arg()`` — either
+        ``fontfile='<path>'`` or ``font='<name>'``.
+        """
         safe = _escape_drawtext(text)
         alpha_expr = f"if(lt(t,{fade_start:.1f}),0,min((t-{fade_start:.1f})/0.3,1))"
         return (
             f"drawtext=text='{safe}'"
-            f":font='{font}'"
+            f":{font_spec}"
             f":fontsize={fontsize}"
             f":fontcolor={fontcolor}"
             f":x={x}"
@@ -514,19 +543,20 @@ def _dt(
             ":fix_bounds=1"
         )
 
-    # Y positions scaled to video height
-    y_eyebrow = int(height * 0.14)
-    y_chinese_label = y_eyebrow + int(height / 25)
-    y_channel = y_chinese_label + int(height / 22)
-    y_channel_url = y_channel + int(height / 20)
-    y_title = (y_channel_url if channel_url else y_channel) + int(height / 22)
-    y_video_url = y_title + int(height / 28)
-    y_decl_zh_1 = y_video_url + int(height / 20)
-    y_decl_zh_2 = y_decl_zh_1 + int(height / 40)
-    y_decl_zh_3 = y_decl_zh_2 + int(height / 40)
-    y_decl_en_1 = y_decl_zh_3 + int(height / 30)
-    y_decl_en_2 = y_decl_en_1 + int(height / 44)
-    y_decl_en_3 = y_decl_en_2 + int(height / 44)
+    # Y positions: vertically centered with generous spacing
+    # Total content height ~50% of frame, starting at ~28%
+    y_eyebrow = int(height * 0.22)
+    y_chinese_label = y_eyebrow + int(height * 0.04)
+    y_channel = y_chinese_label + int(height * 0.05)
+    y_channel_url = y_channel + int(height * 0.055)
+    y_title = (y_channel_url if channel_url else y_channel) + int(height * 0.06)
+    y_video_url = y_title + int(height * 0.04)
+    y_decl_zh_1 = y_video_url + int(height * 0.06)
+    y_decl_zh_2 = y_decl_zh_1 + int(height * 0.03)
+    y_decl_zh_3 = y_decl_zh_2 + int(height * 0.03)
+    y_decl_en_1 = y_decl_zh_3 + int(height * 0.04)
+    y_decl_en_2 = y_decl_en_1 + int(height * 0.028)
+    y_decl_en_3 = y_decl_en_2 + int(height * 0.028)
 
     x_left = str(left_margin)
     x_brand = f"w-tw-{int(width * 0.04)}"
@@ -545,7 +575,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             "ORIGINAL VIDEO FROM",
-            "Arial",
+            _font_arg(_FONT_EN_REGULAR, "Arial"),
             max(1, int(height / 54)),
             "white@0.3",
             x_left,
@@ -560,7 +590,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             "原始影片來自",
-            "serif",
+            _font_arg(_FONT_ZH_REGULAR, "serif"),
             max(1, int(height / 42)),
             "white@0.6",
             x_left,
@@ -575,7 +605,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             channel,
-            "Arial",
+            _font_arg(_FONT_EN_BOLD, "Arial"),
             max(1, int(height / 17)),
             "white@1.0",
             x_left,
@@ -591,7 +621,7 @@ def _next_start() -> float:
         blocks.append(
             _dt(
                 channel_url,
-                "Arial",
+                _font_arg(_FONT_EN_REGULAR, "Arial"),
                 max(1, int(height / 49)),
                 "white@0.35",
                 x_left,
@@ -606,7 +636,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             video_title,
-            "serif",
+            _font_arg(_FONT_ZH_REGULAR, "serif"),
             max(1, int(height / 34)),
             "white@0.7",
             x_left,
@@ -621,7 +651,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             video_url,
-            "Arial",
+            _font_arg(_FONT_EN_REGULAR, "Arial"),
             max(1, int(height / 45)),
             "white@0.5",
             x_left,
@@ -633,7 +663,7 @@ def _next_start() -> float:
 
     # Chinese declaration (3 lines)
     decl_zh = [
-        "翻譯字幕由開源專案 BilingualSub 產生",
+        "翻譯字幕使用開源專案 BilingualSub 製作",
         "所有內容及著作權屬於原始創作者所有",
         "如需移除，請聯繫上傳者",  # noqa: RUF001
     ]
@@ -643,7 +673,7 @@ def _next_start() -> float:
         blocks.append(
             _dt(
                 line,
-                "serif",
+                _font_arg(_FONT_ZH_REGULAR, "serif"),
                 max(1, int(height / 45)),
                 "white@0.45",
                 x_left,
@@ -655,7 +685,7 @@ def _next_start() -> float:
 
     # English declaration (3 lines)
     decl_en = [
-        "Subtitles generated by BilingualSub (open source)",
+        "Subtitles created with BilingualSub (open source)",
         "All content and copyrights belong to the original creator",
         "For removal requests, please contact the uploader",
     ]
@@ -665,7 +695,7 @@ def _next_start() -> float:
         blocks.append(
             _dt(
                 line,
-                "Arial",
+                _font_arg(_FONT_EN_REGULAR, "Arial"),
                 max(1, int(height / 49)),
                 "white@0.35",
                 x_left,
@@ -679,7 +709,7 @@ def _next_start() -> float:
     blocks.append(
         _dt(
             "BilingualSub",
-            "Arial",
+            _font_arg(_FONT_EN_REGULAR, "Arial"),
             max(1, int(height / 54)),
             "white@0.25",
             x_brand,