mp433.7 KB
Countdown with Timecode (MP4)
A six-second countdown (5→0) with a sweeping second-arc, a burned-in SS:FF timecode, and a beep on each second — a slate/leader fixture for testing timecode reading, frame-accurate seeking, and sync.
Specifications
- Resolution
- 480x270
- Fps
- 30
- Duration
- 6s
- Timecode
- SS:FF burned in
- Audio
- beep each second
- Codec
- H.264 + AAC
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="countdown-timecode.mp4"></video>Related files
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- 3gp3GP — Mobile H.264 ClipThe clip as 3GP — the 3GPP mobile container from the feature-phone era. For testing 3GP demuxing and conversion.
- mp460 fps Clip (MP4)A 60 frames-per-second clip with a smoothly sweeping marker — double the usual frame rate. A fixture for testing high-frame-rate playback, frame-rate detection, and fps conversion (60→30 decimation).
- mp4A/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.
- aviAVI — DivX (MPEG-4 ASP) ClipThe clip as DivX-style MPEG-4 ASP in an AVI container — the codec that defined early desktop video. For testing MPEG-4 Part 2 decoding and AVI conversion.
- aviAVI — Motion-JPEG ClipThe clip as Motion-JPEG in a classic AVI (RIFF) container — every frame an independent JPEG. For testing legacy AVI readers, MJPEG decoding, and AVI→modern-codec conversion.
Generated by generation/video_realistic.py. Free for any use, no attribution required — license.