testsrc

Sample rates

16-bit PCM from 8 kHz to 192 kHz, including the 44.1 kHz family (11.025, 22.05, 88.2 and 176.4 kHz) that resamplers see less often.

The files

13 files in snapshot 2026-11-02. Each one's full fact sheet and recipe: GET /v1/cases/{id}, no token needed.

What's in every file

Every video carries its frame number and timecode, burned in at the top left, a frame code along the bottom that the checker reads, and a white flash in the first three frames of every second. The audio carries a tone with a 40 ms beep at the start of every second. So a test can tell which frame is on screen, whether any were dropped, and whether sound and picture line up.

How they were verified

Before publishing, every file was probed and decoded by FFmpeg 7.1.5-0+deb13u1 and GStreamer 1.26.2 (sidecar subtitle files are probed only), and every file with video was played through the testsrc checker, which reads the frame code to confirm frames, timing, orientation, aspect and colour.

Use them

# one file's facts
curl https://testsrc.com/v1/cases/sample-rate/8000.wav

# play every file in this category through your player and check what it showed
testsrc run --player libvlc sample-rate/

See the API reference for tokens, quotas and snapshots.

testsrc is in early access. Free for open-source projects, $99/month per organisation for companies.

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Other baseline categories