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Realtime Error Detection

Realtime Error Detection (RED) is Closed Caption Creator's authoring-time quality layer. Rather than waiting until a review pass at the end of a project, RED monitors every caption event as you work and displays a visual indicator whenever an event violates one of the configured thresholds. This makes it possible to catch and correct problems at the moment they are introduced, which is far less disruptive than discovering them during a final QC pass over a completed file.

How It Works​

RED settings are configured per event group, which means different groups in the same project can have different rules. A closed caption track destined for a broadcast SCC delivery may need stricter reading-speed limits than a subtitle track for an online platform, and RED accommodates that by keeping its configuration at the event-group level.

When an event violates a threshold, a small error badge appears directly on that event in the editor. The badge is colour-coded to indicate whether the problem is related to timing, content, or a review flag. This inline feedback allows captioners to immediately understand what is wrong and make a correction without leaving the editing context.

Configuring Error Detection Settings​

To open the error detection settings for an event group, click the menu icon next to the event group's tab and select Settings. This opens the Edit Event Group window.

At the bottom of the Edit Event Group window you will find the error detection controls. Each field accepts a numeric threshold:

Max Characters Per Second (CPS) sets the upper limit on reading speed expressed as characters per second, including spaces and punctuation. Events that exceed this rate will be flagged. The CPS threshold is one of the most commonly used checks because it directly affects viewer accessibility — captions that are on screen too briefly relative to their length cannot be read comfortably.

Max Words Per Minute (WPM) provides an alternative measure of reading speed for workflows that prefer words-per-minute over characters-per-second. Both checks can be active simultaneously, or one can be disabled by setting it to a very high value.

Max Characters Per Line enforces a maximum character count for any single line within an event. This is important for ensuring captions remain within the safe area and do not wrap unexpectedly on viewer devices.

Max Lines caps the number of text lines an event may contain. Most broadcast delivery specifications allow a maximum of two or four lines.

Min Duration and Max Duration define the acceptable range for how long an event may remain on screen, expressed in seconds. Events shorter than the minimum may not be readable; events longer than the maximum may violate the requirements of the target platform.

Overlap Detection flags any event whose start timecode falls before the end timecode of the immediately preceding event. Overlaps cause display problems in most subtitle formats and are rejected outright by some delivery specifications.

Illegal Characters checks for characters that are not valid in the target format. This is particularly relevant for EIA-608 closed captions, which are limited to a defined character set.

Disabling a Check​

If a particular threshold is not relevant to your current project, it should be turned off rather than left with a default value that may produce false positives. The conventional approach is to set the threshold to a very high number — 9999 is the standard value used throughout Closed Caption Creator — which effectively disables the check without removing it from your saved configuration. When you return to a project type where that check is needed, you can restore the actual threshold without having to reconfigure the field from scratch.

Settings Are Saved Across Projects​

Error Detection Settings are saved to your profile, so future event groups will automatically inherit the same thresholds. This is particularly useful for captioners who work repeatedly within the same delivery specification: configure the rules once, and every new event group you create will immediately have the correct thresholds applied.

Video Tutorials​