Match and mux in dropped external subtitles

Drag in subtitle files alongside .mkv files and they're matched to the right video by episode code (S04E06, zero-padding and separator insensitive, plus 4x06 as a fallback) and muxed in as extra subtitle tracks. Any subtitle format mkvmerge accepts is recognized: SRT, (S)SA, VobSub, WebVTT, PGS/SUP, USF, SAMI, TTML/DFXP, STL, Kate. Matching works regardless of drop order — subtitles dropped before their video are held pending until a matching video shows up, and vice versa. Language, forced, and SDH flags are guessed from common filename tokens (e.g. "eng", "forced", "sdh") to set the muxed track's language/name/flags; unmatched subtitles are reported in the status bar.
2026-07-08 10:37:56 +02:00
parent 304d9ad047
commit c7c125d40b
9 changed files with 511 additions and 21 deletions
@@ -258,12 +258,13 @@ public class MkvService
        IReadOnlyList<int> videoKeepIds,
        IReadOnlyList<int> audioKeepIds,
        IReadOnlyList<int> subtitleKeepIds,
+        IReadOnlyList<ExternalSubtitleTrack>? externalSubtitles = null,
        IProgress<ProcessingProgress>? progress = null,
        CancellationToken ct = default)
    {
        return StripTracksInternalAsync(
            filePath, Path.GetFileName(filePath), outputFilePath,
-            videoKeepIds, audioKeepIds, subtitleKeepIds,
+            videoKeepIds, audioKeepIds, subtitleKeepIds, externalSubtitles,
            progress, ct);
    }

@@ -281,6 +282,7 @@ public class MkvService
            null,                  // null = keep all video
            scan.AudioKeepIds,
            scan.SubtitleKeepIds,
+            null,
            progress, ct);
    }

@@ -386,6 +388,7 @@ public class MkvService
        IReadOnlyList<int>? videoKeepIds,
        IReadOnlyList<int>? audioKeepIds,
        IReadOnlyList<int>? subtitleKeepIds,
+        IReadOnlyList<ExternalSubtitleTrack>? externalSubtitles,
        IProgress<ProcessingProgress>? progress,
        CancellationToken ct)
    {
@@ -422,16 +425,52 @@ public class MkvService
            AddTrackTypeArgs(psi, "--audio-tracks", "--no-audio", audioKeepIds);
            AddTrackTypeArgs(psi, "--subtitle-tracks", "--no-subtitles", subtitleKeepIds);

-            // The one subtitle track the user chose to keep is always flagged
-            // as the default subtitle track in the output.
+            // Only one subtitle track in the whole output should ever be
+            // flagged default. If any external subtitle is marked default,
+            // it takes priority over the kept internal subtitle track.
+            bool hasExternalDefault = externalSubtitles != null && externalSubtitles.Any(s => s.IsDefault);
+
            if (subtitleKeepIds != null && subtitleKeepIds.Count == 1)
            {
                psi.ArgumentList.Add("--default-track-flag");
-                psi.ArgumentList.Add($"{subtitleKeepIds[0]}:yes");
+                psi.ArgumentList.Add(hasExternalDefault ? $"{subtitleKeepIds[0]}:no" : $"{subtitleKeepIds[0]}:yes");
            }

            psi.ArgumentList.Add(filePath);

+            // Append each matched external subtitle file as its own input,
+            // with per-file options (language/name/flags) scoped to it.
+            if (externalSubtitles != null)
+            {
+                foreach (var sub in externalSubtitles)
+                {
+                    if (!string.IsNullOrEmpty(sub.Language) && !string.Equals(sub.Language, "und", StringComparison.OrdinalIgnoreCase))
+                    {
+                        psi.ArgumentList.Add("--language");
+                        psi.ArgumentList.Add($"0:{sub.Language}");
+                    }
+                    if (!string.IsNullOrWhiteSpace(sub.TrackName))
+                    {
+                        psi.ArgumentList.Add("--track-name");
+                        psi.ArgumentList.Add($"0:{sub.TrackName}");
+                    }
+                    if (sub.Forced)
+                    {
+                        psi.ArgumentList.Add("--forced-display-flag");
+                        psi.ArgumentList.Add("0:yes");
+                    }
+                    if (sub.HearingImpaired)
+                    {
+                        psi.ArgumentList.Add("--hearing-impaired-flag");
+                        psi.ArgumentList.Add("0:yes");
+                    }
+                    psi.ArgumentList.Add("--default-track-flag");
+                    psi.ArgumentList.Add(sub.IsDefault ? "0:yes" : "0:no");
+
+                    psi.ArgumentList.Add(sub.FilePath);
+                }
+            }
+
            using var process = new Process { StartInfo = psi };
            process.Start();

@@ -0,0 +1,105 @@
+using System.IO;
+
+namespace Futonizer.Services;
+
+/// <summary>
+/// Result of scanning an external subtitle's filename for language and
+/// display hints.
+/// </summary>
+public readonly record struct SubtitleLanguageInfo(string Language, bool Forced, bool HearingImpaired, string TrackName);
+
+/// <summary>
+/// Best-effort language/flag detection for external subtitle files, based on
+/// common filename tokens (e.g. "Show.S04E06.eng.srt", "Show.S04E06.forced.srt").
+/// Never throws — falls back to an "und" (undetermined) language with no
+/// track name when nothing recognisable is found.
+/// </summary>
+public static class SubtitleLanguageHelper
+{
+    private static readonly Dictionary<string, string> TokenToIso6392 = new(StringComparer.OrdinalIgnoreCase)
+    {
+        ["en"] = "eng", ["eng"] = "eng", ["english"] = "eng",
+        ["ja"] = "jpn", ["jp"] = "jpn", ["jpn"] = "jpn", ["japanese"] = "jpn",
+        ["es"] = "spa", ["spa"] = "spa", ["spanish"] = "spa", ["esp"] = "spa",
+        ["fr"] = "fre", ["fre"] = "fre", ["fra"] = "fre", ["french"] = "fre",
+        ["de"] = "ger", ["ger"] = "ger", ["deu"] = "ger", ["german"] = "ger",
+        ["it"] = "ita", ["ita"] = "ita", ["italian"] = "ita",
+        ["pt"] = "por", ["por"] = "por", ["portuguese"] = "por", ["ptbr"] = "por",
+        ["ru"] = "rus", ["rus"] = "rus", ["russian"] = "rus",
+        ["zh"] = "chi", ["chi"] = "chi", ["zho"] = "chi", ["chinese"] = "chi", ["cmn"] = "chi", ["yue"] = "chi",
+        ["ko"] = "kor", ["kor"] = "kor", ["korean"] = "kor",
+        ["ar"] = "ara", ["ara"] = "ara", ["arabic"] = "ara",
+        ["nl"] = "dut", ["dut"] = "dut", ["nld"] = "dut", ["dutch"] = "dut",
+        ["sv"] = "swe", ["swe"] = "swe", ["swedish"] = "swe",
+        ["no"] = "nor", ["nor"] = "nor", ["norwegian"] = "nor",
+        ["da"] = "dan", ["dan"] = "dan", ["danish"] = "dan",
+        ["fi"] = "fin", ["fin"] = "fin", ["finnish"] = "fin",
+        ["pl"] = "pol", ["pol"] = "pol", ["polish"] = "pol",
+        ["tr"] = "tur", ["tur"] = "tur", ["turkish"] = "tur",
+        ["vi"] = "vie", ["vie"] = "vie", ["vietnamese"] = "vie",
+        ["th"] = "tha", ["tha"] = "tha", ["thai"] = "tha",
+        ["id"] = "ind", ["ind"] = "ind", ["indonesian"] = "ind",
+        ["he"] = "heb", ["heb"] = "heb", ["hebrew"] = "heb",
+        ["hin"] = "hin", ["hindi"] = "hin",
+        ["cs"] = "cze", ["cze"] = "cze", ["ces"] = "cze", ["czech"] = "cze",
+        ["el"] = "gre", ["gre"] = "gre", ["ell"] = "gre", ["greek"] = "gre",
+        ["hu"] = "hun", ["hun"] = "hun", ["hungarian"] = "hun",
+        ["ro"] = "rum", ["rum"] = "rum", ["ron"] = "rum", ["romanian"] = "rum",
+        ["uk"] = "ukr", ["ukr"] = "ukr", ["ukrainian"] = "ukr",
+    };
+
+    private static readonly Dictionary<string, string> Iso6392ToDisplayName = new(StringComparer.OrdinalIgnoreCase)
+    {
+        ["eng"] = "English", ["jpn"] = "Japanese", ["spa"] = "Spanish", ["fre"] = "French",
+        ["ger"] = "German", ["ita"] = "Italian", ["por"] = "Portuguese", ["rus"] = "Russian",
+        ["chi"] = "Chinese", ["kor"] = "Korean", ["ara"] = "Arabic", ["dut"] = "Dutch",
+        ["swe"] = "Swedish", ["nor"] = "Norwegian", ["dan"] = "Danish", ["fin"] = "Finnish",
+        ["pol"] = "Polish", ["tur"] = "Turkish", ["vie"] = "Vietnamese", ["tha"] = "Thai",
+        ["ind"] = "Indonesian", ["heb"] = "Hebrew", ["hin"] = "Hindi", ["cze"] = "Czech",
+        ["gre"] = "Greek", ["hun"] = "Hungarian", ["rum"] = "Romanian", ["ukr"] = "Ukrainian",
+    };
+
+    private static readonly char[] TokenSeparators = { '.', '_', '-', ' ', '(', ')', '[', ']' };
+
+    public static SubtitleLanguageInfo Detect(string fileName)
+    {
+        string stem = Path.GetFileNameWithoutExtension(fileName);
+        var tokens = stem.Split(TokenSeparators, StringSplitOptions.RemoveEmptyEntries);
+
+        string language = "und";
+        bool forced = false;
+        bool hearingImpaired = false;
+
+        foreach (var token in tokens)
+        {
+            if (string.Equals(token, "forced", StringComparison.OrdinalIgnoreCase))
+            {
+                forced = true;
+                continue;
+            }
+            if (string.Equals(token, "sdh", StringComparison.OrdinalIgnoreCase)
+                || string.Equals(token, "cc", StringComparison.OrdinalIgnoreCase))
+            {
+                hearingImpaired = true;
+                continue;
+            }
+            if (language == "und" && TokenToIso6392.TryGetValue(token, out var iso))
+                language = iso;
+        }
+
+        string trackName = string.Empty;
+        if (Iso6392ToDisplayName.TryGetValue(language, out var displayName))
+            trackName = displayName;
+
+        if (forced || hearingImpaired)
+        {
+            var suffixes = new List<string>();
+            if (forced) suffixes.Add("Forced");
+            if (hearingImpaired) suffixes.Add("SDH");
+            string suffix = $" ({string.Join(", ", suffixes)})";
+            trackName = string.IsNullOrEmpty(trackName) ? suffix.Trim(' ', '(', ')') : trackName + suffix;
+        }
+
+        return new SubtitleLanguageInfo(language, forced, hearingImpaired, trackName);
+    }
+}
@@ -0,0 +1,61 @@
+using System.IO;
+using System.Text.RegularExpressions;
+
+namespace Futonizer.Services;
+
+/// <summary>
+/// Recognises subtitle files by extension and extracts a normalized episode
+/// code (e.g. "S04E06") from a filename, used to match dropped subtitle
+/// files to the video file with the same episode code.
+/// </summary>
+public static class SubtitleMatcher
+{
+    /// <summary>
+    /// Every subtitle container/format extension mkvmerge (and therefore
+    /// Futonizer) can mux in: SubRip, (Advanced) SubStation Alpha, VobSub,
+    /// WebVTT, HDMV/PGS, Universal Subtitle Format, SAMI, TTML/DFXP, EBU-STL,
+    /// MicroDVD/SubViewer (both commonly saved with a plain ".sub" extension),
+    /// and Kate.
+    /// </summary>
+    public static readonly string[] SupportedExtensions =
+    {
+        ".srt", ".ass", ".ssa", ".sub", ".idx", ".vtt", ".webvtt",
+        ".sup", ".pgs", ".usf", ".smi", ".sami", ".ttml", ".dfxp",
+        ".stl", ".kate",
+    };
+
+    public static bool IsSubtitleFile(string path)
+    {
+        string ext = Path.GetExtension(path);
+        return !string.IsNullOrEmpty(ext)
+               && SupportedExtensions.Contains(ext, StringComparer.OrdinalIgnoreCase);
+    }
+
+    // "S04E06", "S4E6", "S04 E06", "S04-E06", "S04.E06" — the standard scene/anime tagging scheme.
+    private static readonly Regex SeasonEpisodeRegex =
+        new(@"S(\d{1,4})[\s._-]*E(\d{1,4})", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+
+    // Fallback: "4x06" style season x episode separator.
+    private static readonly Regex SeasonXEpisodeRegex =
+        new(@"(?<![\d.])(\d{1,2})x(\d{2,3})(?!\d)", RegexOptions.IgnoreCase | RegexOptions.Compiled);
+
+    /// <summary>
+    /// Extracts and normalizes the episode code from a filename (e.g.
+    /// "Show.S4E6.1080p.mkv" and "Show - 04x06 - Title.srt" both return
+    /// "S04E06"), so files can be matched regardless of zero-padding or
+    /// separator style. Returns null if no episode code is found.
+    /// </summary>
+    public static string? ExtractEpisodeCode(string fileName)
+    {
+        var match = SeasonEpisodeRegex.Match(fileName);
+        if (!match.Success)
+            match = SeasonXEpisodeRegex.Match(fileName);
+
+        if (!match.Success) return null;
+
+        if (!int.TryParse(match.Groups[1].Value, out int season)) return null;
+        if (!int.TryParse(match.Groups[2].Value, out int episode)) return null;
+
+        return $"S{season:D2}E{episode:D2}";
+    }
+}