A/V Sync — Beep + Flash (MP4, with audio)
A five-second clip that flashes white and plays a 1 kHz beep on every whole second — the first clip in the library WITH an audio track. A direct fixture for measuring and correcting audio/video sync (lip-sync) offset.
Specifications
- Resolution
- 480x270
- Fps
- 30
- Duration
- 5s
- Audio
- AAC — 1 kHz beep each second
- Codec
- H.264 + AAC
- Note
- white flash aligns with the beep for A/V-sync testing
What is a .mp4 file?
MP4 (MPEG-4 Part 14) is a widely supported multimedia container based on ISOBMFF that holds video, audio, subtitles, and metadata, most commonly H.264 or H.265 video with AAC audio. It supports streaming, chapters, and multiple tracks. It is the dominant format for distributing and playing digital video.
How to use this file
Use an example MP4 to test container demuxing, track and codec detection, seeking and streaming, and transcoding or thumbnail-extraction pipelines.
Code examples
<video controls preload="metadata" width="640" src="av-sync.mp4"></video>Related files
- mp4SMPTE Colour Bars + 1 kHz Tone (MP4)Standard SMPTE-style colour bars with a 1 kHz reference tone — the classic broadcast test pattern. A fixture for calibrating colour, testing decoders, and verifying audio alongside a known video signal.
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- wav1 kHz Tone @ 44100 Hz Sample Rate (WAV)A 1 kHz sine tone sampled at 44100 Hz — part of a sample-rate ladder (8/16/44.1/48/96 kHz) of the identical tone, for testing resampling, sample-rate detection, and aliasing.
- wav1 kHz Tone @ 48000 Hz Sample Rate (WAV)A 1 kHz sine tone sampled at 48000 Hz — part of a sample-rate ladder (8/16/44.1/48/96 kHz) of the identical tone, for testing resampling, sample-rate detection, and aliasing.
- wav1 kHz Tone @ 8000 Hz Sample Rate (WAV)A 1 kHz sine tone sampled at 8000 Hz — part of a sample-rate ladder (8/16/44.1/48/96 kHz) of the identical tone, for testing resampling, sample-rate detection, and aliasing.
- wav1 kHz Tone @ 96000 Hz Sample Rate (WAV)A 1 kHz sine tone sampled at 96000 Hz — part of a sample-rate ladder (8/16/44.1/48/96 kHz) of the identical tone, for testing resampling, sample-rate detection, and aliasing.
Generated by generation/video_realistic.py. Free for any use, no attribution required — license.