# Sample AAC audio files for testing, free, CC0 and hotlinkable 1 AAC test file of 490.4 KB. A direct URL, the file's SHA-256 and CC0, so curl and CI can fetch it with no signup and no keys. The page: . AAC is the lossy codec behind most streaming audio. These files carry it as a bare ADTS stream, with no MP4 container around the frames: the shape broadcast feeds and HLS audio arrive in. That makes `aac/adts-30s.aac` a good test of whether a decoder can find frame boundaries on its own, or quietly expects the box structure of an M4A file. `aac/adts-30s.aac` is a 440 Hz sine wave, thirty seconds long, 48 kHz stereo, at 130.6 kbps counting each frame's ADTS header. A pure tone is easy to check by ear and by spectrum: any pitch shift, dropout or channel problem is obvious. Use it to test upload validation that inspects a file's first bytes, players that must stream rather than seek, and transcoders that need to wrap raw AAC in a container. For the same audio inside MP4, see [M4A](https://loremfile.dev/m4a); for the transport stream that often carries ADTS audio, see [TS](https://loremfile.dev/ts). ## Files | Path | Size | MIME | Properties | |---|---|---|---| | [`aac/adts-30s.aac`](https://loremfile.dev/aac/adts-30s.aac) | 490.4 KB (490,385 bytes) | `audio/aac` | 30.042 s, aac, 48 kHz, 2 channels | The same list as JSON: .