commit c9c476160e1e6318591e711db5cb6c29389cbadb
Author: Esa Kataja <ekataja@gmail.com>
Date:   Thu Aug 14 16:12:13 2025 +0300

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..6d9f9d0
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,6 @@
+*.srt
+*.log
+*.idx
+*.sub
+*.sup
+*.mkv
\ No newline at end of file
diff --git a/.vscode/settings.json b/.vscode/settings.json
new file mode 100644
index 0000000..7fe6ae6
--- /dev/null
+++ b/.vscode/settings.json
@@ -0,0 +1,6 @@
+{
+  "deno.enable": true,
+  "deno.lint": true,
+  "editor.defaultFormatter": "denoland.vscode-deno",
+  "editor.formatOnSave": true
+}
diff --git a/deno.json b/deno.json
new file mode 100644
index 0000000..a3430a7
--- /dev/null
+++ b/deno.json
@@ -0,0 +1,8 @@
+{
+  "tasks": {
+    "dev": "deno run --watch --allow-run --allow-write --allow-read src/main.ts"
+  },
+  "imports": {
+    "@std/assert": "jsr:@std/assert@1"
+  }
+}
diff --git a/src/main.ts b/src/main.ts
new file mode 100644
index 0000000..ae66324
--- /dev/null
+++ b/src/main.ts
@@ -0,0 +1,110 @@
+import { videoFile } from "./types.ts";
+
+const input = "/home/esa/Videos/tmp/3MUSKETEERS_D1_PAL/B3_t00.mkv";
+
+// TODO: Check if mkvmerge, ffmpeg and vobsub2srt are installed.
+
+const lang_codes = {
+  "eng": "en",
+  "fin": "fi",
+};
+
+function main() {
+  const command = new Deno.Command("mkvmerge", {
+    args: ["-J", input],
+  });
+
+  const { code, stdout, stderr } = command.outputSync();
+
+  const mkvmerge_output = JSON.parse(
+    new TextDecoder().decode(stdout),
+  ) as videoFile;
+  const error = new TextDecoder().decode(stderr);
+  if (code !== 0) {
+    console.error(error);
+    return;
+  }
+  const languages_in_file: Record<string, string> = {};
+  for (const track of mkvmerge_output.tracks) {
+    if (!(track.type === "subtitles")) {
+      continue;
+    }
+    const lang =
+      lang_codes[track.properties.language as keyof typeof lang_codes];
+    if (!lang) {
+      console.log("Unknown language: " + track.properties.language);
+      continue;
+    }
+    console.log(track.id + " " + lang);
+    languages_in_file[track.id] = lang;
+  }
+  console.log(languages_in_file);
+  const formatted_language_string = Object.entries(languages_in_file)
+    .map(([id, lang]) => `${id}:${lang}`);
+  console.log(formatted_language_string);
+  const rip_cmd = new Deno.Command("mkvextract", {
+    args: ["tracks", input, ...formatted_language_string],
+  });
+  rip_cmd.outputSync();
+
+  for (const [id, lang] of Object.entries(languages_in_file)) {
+    const convert_cmd = new Deno.Command("vobsub2srt", {
+      args: ["-l", lang, "--blacklist", "|", lang],
+    });
+    convert_cmd.outputSync();
+    Deno.remove(lang + ".idx");
+    Deno.remove(lang + ".sub");
+  }
+
+  const ffmpeg_cmd_raw = [];
+  const subTracksById = new Map(
+    mkvmerge_output.tracks
+      .filter((t) => t.type === "subtitles")
+      .map((t) => [String(t.id), t]),
+  );
+  const entries = Object.entries(languages_in_file);
+
+  // 1) Add all inputs first
+  for (const [, lang] of entries) {
+    ffmpeg_cmd_raw.push("-i", `${lang}.srt`);
+  }
+
+  // 2) Explicitly set subtitle codec copy (optional but clearer)
+  ffmpeg_cmd_raw.push("-c:s", "copy");
+
+  // 3) Per-subtitle options after all inputs
+  let i = 0;
+  for (const [id, lang] of entries) {
+    const iso639_2 = subTracksById.get(id)?.properties.language ?? "und";
+    const inputIndex = i; // each SRT is its own input in order
+    // Map the subtitle stream from the ith SRT input
+    ffmpeg_cmd_raw.push("-map", `${inputIndex}:s:0`);
+    // Set language metadata for subtitle stream i in the output
+    ffmpeg_cmd_raw.push(`-metadata:s:s:${i}`, `language=${iso639_2}`);
+    // Optionally set default disposition for Finnish
+    if (lang === "fi") {
+      ffmpeg_cmd_raw.push(`-disposition:s:${i}`, "default");
+    }
+    i++;
+  }
+
+  // 4) Output last
+  ffmpeg_cmd_raw.push("-y", "subit.mkv");
+  const ffmpeg_cmd = new Deno.Command("ffmpeg", {
+    args: ffmpeg_cmd_raw,
+  });
+  const { code: ffmpeg_code, stdout: ffmpeg_stdout, stderr: ffmpeg_stderr } =
+    ffmpeg_cmd.outputSync();
+  const ffmpeg_error = new TextDecoder().decode(ffmpeg_stderr);
+  if (ffmpeg_code !== 0) {
+    console.error(ffmpeg_error);
+    return;
+  }
+  for (const [_, lang] of Object.entries(languages_in_file)) {
+    Deno.remove(lang + ".srt");
+  }
+}
+
+if (import.meta.main) {
+  main();
+}
diff --git a/src/types.ts b/src/types.ts
new file mode 100644
index 0000000..0ac93a7
--- /dev/null
+++ b/src/types.ts
@@ -0,0 +1,32 @@
+export interface Track {
+  id: number;
+  type: string;
+  codec: string;
+  properties: TrackProperties;
+}
+
+export interface TrackProperties {
+  codec_id: string;
+  codec_private_data: string;
+  codec_private_length: number;
+  default_track: boolean;
+  enabled_track: boolean;
+  forced_track: boolean;
+  language: string;
+  num_index_entries: number;
+  number: number;
+  tag__statistics_tags: string;
+  tag__statistics_writing_app: string;
+  tag__statistics_writing_date_utc: string;
+  tag_bps: string;
+  tag_duration: string;
+  tag_number_of_bytes: string;
+  tag_number_of_frames: string;
+  tag_source_id: string;
+  uid: number;
+}
+
+export interface videoFile {
+  file_name: string;
+  tracks: Track[];
+}