SubtitleEdit/subtitleedit · error · InvalidOperationException

No subtitle tracks in Matroska file: {filePath}

Error message

No subtitle tracks in Matroska file: {filePath}

What it means

Thrown when a valid Matroska file contains no subtitle tracks — matroska.GetTracks(true) (subtitle-only filter) returns an empty list. The container is fine but has nothing to extract: only video/audio/data tracks exist.

Source

Thrown at src/seconv/Core/ContainerSubtitleLoader.cs:248

                $"MXF contained {subtitleTexts.Count} candidate subtitle essence(s) but none parsed as a known format: {filePath}");
        }

        return tracks;
    }

    private static List<LoadedTrack> LoadMatroska(string filePath, ConversionOptions options)
    {
        var tracks = new List<LoadedTrack>();
        using var matroska = new MatroskaFile(filePath);
        if (!matroska.IsValid)
        {
            throw new InvalidOperationException($"Invalid Matroska file: {filePath}");
        }

        var subtitleTracks = matroska.GetTracks(true);
        if (subtitleTracks.Count == 0)
        {
            throw new InvalidOperationException($"No subtitle tracks in Matroska file: {filePath}");
        }

        foreach (var track in subtitleTracks)
        {
            if (options.ForcedOnly && !track.IsForced)
            {
                continue;
            }
            if (options.TrackNumbers.Count > 0 && !options.TrackNumbers.Contains(track.TrackNumber))
            {
                continue;
            }

            // Image-codec tracks: PGS goes through Tesseract OCR; VobSub deferred.
            if (track.CodecId.Equals("S_HDMV/PGS", StringComparison.OrdinalIgnoreCase))
            {
                try
                {

View on GitHub (pinned to 17a9f07487)

Solutions

1. Check tracks with mkvinfo/ffprobe ('Stream #0:X(subtitle)') to confirm subtitles are absent.
2. Provide an external subtitle file (.srt/.ass) instead of the MKV.
3. If subtitles should be present, re-mux the original with mkvmerge including the subtitle track.

// Check for subtitle tracks before the loader's guard fires.
using var mk = new MatroskaFile(filePath);
if (mk.IsValid && mk.GetTracks(true).Count == 0)
    return Error($"No subtitle tracks in {filePath}");

try { tracks = ContainerSubtitleLoader.TryLoadTracks(filePath, options); }
catch (InvalidOperationException ex) when (ex.Message.Contains("No subtitle tracks in Matroska"))
{ Console.Error.WriteLine(ex.Message); return; }

When it happens

Trigger: Loading a .mkv/.mks that has zero tracks flagged as subtitle tracks (ContainerSubtitleLoader.cs:246). Common with video-only releases or MKVs muxed without subtitle tracks.

Common situations: A video-only MKV; a release whose subtitles are in a separate .srt rather than muxed in; an MKV where subtitle tracks were stripped by a re-mux.

Related errors

• No VobSub subtitles in MKV track #{track.TrackNumber}.
• No PGS subtitles in MKV track #{track.TrackNumber}.
• Invalid Matroska file: {filePath}
• No subtitle tracks in MP4 file: {filePath}
• Unable to access bitmap pixel data.

AI-assisted analysis of SubtitleEdit/subtitleedit@17a9f07487 (2026-08-13). Data as JSON: /api/errors/8410dfd14696c28f. Report an issue: GitHub.