# Audio Caption Sync Checker

Compare SRT or WebVTT cue timing with likely speech activity and flag timing drift.

> Canonical page: https://elysiatools.com/en/tools/audio-caption-sync-checker

- **Category:** Media

- **Keywords:** caption sync, subtitle timing, srt, webvtt, speech activity

## Overview

The checker parses caption cues, detects likely speech-range activity, and compares each cue to the activity segment with the greatest overlap. It reports start drift and overlap status. It does not transcribe audio or verify caption wording, and it cannot guarantee speech detection in music or noisy recordings.

## Inputs

- **Audio File** (file): Select audio to compare
- **Caption File** (file): Select an SRT or WebVTT file
- **Caption Format** (select)
- **Timing Tolerance (s)** (number)

## When to use

- When you need to verify if a translated SRT or WebVTT file matches the original audio track before publishing.
- When checking automated subtitle exports for timing drift or lag across long audio recordings.
- When validating subtitle alignment tolerances before importing captions into video editing software.

## How it works

- Upload your audio file and the corresponding SRT or WebVTT caption file.
- Select the caption format or let the tool auto-detect it, then set your timing tolerance threshold in seconds.
- The tool analyzes the audio for speech-range activity and compares the timing of each caption cue to the detected speech segments.
- It outputs a JSON report detailing start drift, overlap status, and flags cues that exceed your tolerance threshold.

## Use cases

- Quality control for localized SRT files against localized voiceover tracks.
- Automated pre-flight checks for video production pipelines to catch out-of-sync WebVTT files.
- Auditing long-form podcast transcripts and captions for cumulative timing drift.

## Frequently asked questions

### Does this tool transcribe my audio?

No, it only detects speech activity timing and does not transcribe or verify the actual words spoken.

### What caption formats are supported?

The tool supports SRT and WebVTT caption files.

### How does the timing tolerance setting work?

It defines the maximum allowed difference in seconds between the caption start time and the detected speech activity before a drift is flagged.

### Can it detect speech in noisy audio or background music?

Speech detection accuracy may decrease in noisy environments or tracks with heavy background music.

### What does the output JSON report contain?

It contains a list of caption cues with their start drift, overlap status, and flags indicating if they exceed the tolerance threshold.

## Related tools

- [Audio Dictation Quality Checker](https://elysiatools.com/en/tools/audio-dictation-quality-checker): Check whether audio is suitable for transcription using SNR, clipping, format, channels, and speech activity.
- [Audio Platform Delivery Checker](https://elysiatools.com/en/tools/audio-platform-delivery-checker): Check podcast or spoken-audio files against platform delivery profiles, including codec, loudness, metadata, chapters, cover art, and decodability.
- [Audio Duration Checker](https://elysiatools.com/en/tools/audio-duration-checker): Get the exact duration of an audio file
- [Audio Mix Translation Checker](https://elysiatools.com/en/tools/audio-mix-translation-checker): Simulate your mix on phone, laptop, earbud, car, club, mono and noisy-street playback, export every render in a ZIP, and report what survives each system.
- [Audio Overlap Speech Detector](https://elysiatools.com/en/tools/audio-overlap-speech-detector): Find likely simultaneous speech-like activity by detecting multiple balanced voice-frequency bands.
- [Audio Caption Timing Shifter](https://elysiatools.com/en/tools/audio-caption-timing-shifter): Shift SRT or WebVTT captions to a likely speech onset or by a manual offset.
- [Language Learning Loop Maker](https://elysiatools.com/en/tools/audio-language-learning-loop-maker): Turn speech phrases into a repeatable practice track with a configurable pause between repetitions.
- [Audio Read-Along Cue Generator](https://elysiatools.com/en/tools/audio-read-along-cue-generator): Generate sentence or word-level timestamp cues from a narration audio and its script, for karaoke-style reading and language learning.

## Samples

- [Copyright-Free MP3 Audio Samples](https://elysiatools.com/en/samples/mp3-samples): Collection of royalty-free audio samples for testing and development purposes including nature sounds, meditation music, and ambient audio
- [Copyright-Free FLAC Audio Samples](https://elysiatools.com/en/samples/flac-samples): Lossless FLAC audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [Copyright-Free WAV Audio Samples](https://elysiatools.com/en/samples/wav-samples): Uncompressed PCM WAV audio samples for testing and development, mirrored from MP3 set with nature sounds and meditation music
- [Speech Learning & Safety Audio Samples](https://elysiatools.com/en/samples/audio-learning-safety-samples): Deterministic synthetic WAV inputs for pronunciation comparison, dictation preflight, alert degradation, and voice privacy tools.

## Related content

- [Audio Analysis and Visualization Tools](https://elysiatools.com/en/hubs/audio-analysis-and-visualization-tools): Visualize audio, inspect stereo, diagnose signal and timing, and check files before delivery.