From 8cd6dfb65aabf6feae08ab28801bef839a14d485 Mon Sep 17 00:00:00 2001
From: rlaphoenix <rlaphoenix@pm.me>
Date: Sat, 2 Dec 2023 17:56:40 +0000
Subject: [PATCH] Implement `--sub-format` in dl to set output subtitle format

The default is still SubRip SRT, but you can now change the output format to almost any of the available Codec options. There is no option to leave the subtitle format as-is yet. I.e., if there's a SRT and WebVTT subtitle, leave them both as-is.

Like always, you can configure a default in your config file, e.g.,

```yaml
dl:
  sub_format: vtt
```

Note though that SSA, SSAv4, fTTML, and fVTT are not yet supported. There are no plans to support fTTML or fVTT.
---
 CONFIG.md             |  8 +++++++-
 devine/commands/dl.py | 38 +++++++++++++++++++++++++++++---------
 2 files changed, 36 insertions(+), 10 deletions(-)

diff --git a/CONFIG.md b/CONFIG.md
index 018e161..1f07f96 100644
--- a/CONFIG.md
+++ b/CONFIG.md
@@ -120,7 +120,7 @@ For example to set the default primary language to download to German,
 lang: de
 ```
 
-or to set `--bitrate=CVBR` for the AMZN service,
+to set `--bitrate=CVBR` for the AMZN service,
 
 ```yaml
 lang: de
@@ -128,6 +128,12 @@ AMZN:
   bitrate: CVBR
 ```
 
+or to change the output subtitle format from the default (SubRip SRT) to WebVTT,
+
+```yaml
+sub_format: vtt
+```
+
 ## downloader (str)
 
 Choose what software to use to download data throughout Devine where needed.
diff --git a/devine/commands/dl.py b/devine/commands/dl.py
index 1224f50..352f3ef 100644
--- a/devine/commands/dl.py
+++ b/devine/commands/dl.py
@@ -102,6 +102,9 @@ class dl:
                   help="Proxy URI to use. If a 2-letter country is provided, it will try get a proxy from the config.")
     @click.option("--group", type=str, default=None,
                   help="Set the Group Tag to be used, overriding the one in config if any.")
+    @click.option("--sub-format", type=click.Choice(Subtitle.Codec, case_sensitive=False),
+                  default=Subtitle.Codec.SubRip,
+                  help="Set Output Subtitle Format, only converting if necessary.")
     @click.option("-V", "--video-only", is_flag=True, default=False,
                   help="Only download video tracks.")
     @click.option("-A", "--audio-only", is_flag=True, default=False,
@@ -261,6 +264,7 @@ class dl:
         lang: list[str],
         v_lang: list[str],
         s_lang: list[str],
+        sub_format: Subtitle.Codec,
         video_only: bool,
         audio_only: bool,
         subs_only: bool,
@@ -575,18 +579,34 @@ class dl:
                             break
                     video_track_n += 1
 
-                with console.status(f"Converting subtitles to {Subtitle.Codec.SubRip}..."):
+                with console.status(f"Converting Subtitles to {sub_format.name}..."):
                     for subtitle in title.tracks.subtitles:
-                        # convert subs to SRT unless it's already SRT, or SSA
-                        if subtitle.codec not in (Subtitle.Codec.SubRip, Subtitle.Codec.SubStationAlphav4):
+                        if subtitle.codec != sub_format:
+                            writer = {
+                                Subtitle.Codec.SubRip: pycaption.SRTWriter,
+                                Subtitle.Codec.SubStationAlpha: None,
+                                Subtitle.Codec.SubStationAlphav4: None,
+                                Subtitle.Codec.TimedTextMarkupLang: pycaption.DFXPWriter,
+                                Subtitle.Codec.WebVTT: pycaption.WebVTTWriter,
+                                # MPEG-DASH box-encapsulated subtitle formats
+                                Subtitle.Codec.fTTML: None,
+                                Subtitle.Codec.fVTT: None,
+                            }[sub_format]
+                            if writer is None:
+                                self.log.error(f"Cannot yet convert {subtitle.codec} to {sub_format.name}...")
+                                sys.exit(1)
+
                             caption_set = subtitle.parse(subtitle.path.read_bytes(), subtitle.codec)
                             subtitle.merge_same_cues(caption_set)
-                            srt = pycaption.SRTWriter().write(caption_set)
-                            # NOW sometimes has this, when it isn't, causing mux problems
-                            srt = srt.replace("MULTI-LANGUAGE SRT\n", "")
-                            subtitle.path.write_text(srt, encoding="utf8")
-                            subtitle.codec = Subtitle.Codec.SubRip
-                            subtitle.move(subtitle.path.with_suffix(".srt"))
+
+                            subtitle_text = writer().write(caption_set)
+                            if sub_format == Subtitle.Codec.SubRip:
+                                # NOW sometimes has this, when it isn't, causing mux problems
+                                subtitle_text = subtitle_text.replace("MULTI-LANGUAGE SRT\n", "")
+
+                            subtitle.path.write_text(subtitle_text, encoding="utf8")
+                            subtitle.codec = sub_format
+                            subtitle.move(subtitle.path.with_suffix(f".{sub_format.value.lower()}"))
 
                 with console.status("Repackaging tracks with FFMPEG..."):
                     has_repacked = False