SubtitleEdit/subtitleedit · error · InvalidOperationException

Unknown time format '{timeFormat}'

Error message

Unknown time format '{timeFormat}'

What it means

Thrown by ClqttJson.LoadSubtitle when the JSON 'meta' object has a 'timeFormat' field whose value is not 'FRAMES' (case-insensitive). The CLQTT importer only supports frame-based timing, so any other value (seconds, milliseconds, or a typo) is rejected before any events are read.

Source

Thrown at src/libse/SubtitleFormats/ClqttJson.cs:53

            var text = sb.ToString().TrimStart();
            if (text.IndexOf("\"events\"", StringComparison.Ordinal) < 0)
            {
                return;
            }

            subtitle.Paragraphs.Clear();
            var parser = new SeJsonParser();
            var frameRate = Configuration.Settings.General.CurrentFrameRate;

            var rootElements = parser.GetRootElements(text);

            var metaElement = rootElements.Find(element => element.Name.Equals("meta", StringComparison.InvariantCultureIgnoreCase));
            if (metaElement != null)
            {
                var timeFormat = parser.GetFirstObject(metaElement.Json, "timeFormat");
                if (!timeFormat.Equals("FRAMES", StringComparison.InvariantCultureIgnoreCase))
                {
                    throw new InvalidOperationException($"Unknown time format '{timeFormat}'");
                }

                var fpsString = parser.GetFirstObject(metaElement.Json, "fps");
                if (fpsString.Equals("FPS_2397", StringComparison.InvariantCultureIgnoreCase))
                {
                    frameRate = 24000.0 / 1001.0;
                }
                else if (fpsString.Equals("FPS_2997", StringComparison.InvariantCultureIgnoreCase))
                {
                    frameRate = 30000.0 / 1001.0;
                }
                else if (fpsString.Equals("FPS_5994", StringComparison.InvariantCultureIgnoreCase))
                {
                    frameRate = 60000.0 / 1001.0;
                }
                else
                {
                    try

View on GitHub (pinned to 17a9f07487)

Solutions

1. Inspect the .clqtt file's meta object and set timeFormat to "FRAMES".
2. Convert the file's timing to frames using its native tool before importing.
3. Upgrade SubtitleEdit — newer builds may support additional time formats.
4. If producing CLQTT output, ensure your exporter writes timeFormat=FRAMES.

Example fix

// before
"meta": { "timeFormat": "seconds", "fps": "FPS_2397" }
// after
"meta": { "timeFormat": "FRAMES", "fps": "FPS_2397" }

// Check meta.timeFormat before importing a CLQTT payload
var timeFormat = parser.GetFirstObject(metaElement.Json, "timeFormat");
if (!timeFormat.Equals("FRAMES", StringComparison.OrdinalIgnoreCase))
{
    // convert or reject instead of letting LoadSubtitle throw
    Console.WriteLine($"Unsupported timeFormat '{timeFormat}'; convert to FRAMES first.");
}

try
{
    new ClqttJson().LoadSubtitle(sub, lines, fileName);
}
catch (InvalidOperationException ex) when (ex.Message.Contains("Unknown time format"))
{
    // inform user the file's timing mode is unsupported
    logger.Warning(ex.Message);
}

When it happens

Trigger: Feeding a .clqtt file whose meta.timeFormat is 'SECONDS', 'ms', 'TIME', empty, or any string other than 'FRAMES'. Also occurs if a future CLQTT spec version introduces a new time format this importer does not yet handle.

Common situations: Using a CLQTT file produced by a tool that emits a different timing mode; version mismatch between the file producer and this SubtitleEdit build; hand-crafted CLQTT JSON.

Related errors

• Unknown type of event #{i + 1}: '{type}'
• Element 'events' not found.
• Parse error in event #{i + 1} style: {ex.Message}
• Parse error in event #{i + 1}: {ex.Message}
• Invalid ASSA time code: {time}

AI-assisted analysis of SubtitleEdit/subtitleedit@17a9f07487 (2026-08-13). Data as JSON: /api/errors/384381a3055f2ef8. Report an issue: GitHub.