Sample AAC Files — Download Raw AAC (ADTS) Test Audio
Advanced Audio Coding (raw ADTS stream) · .aac · MIME type audio/aac
Download a sample AAC file — a raw ADTS stream of AAC-LC audio at 128 kbps. This is AAC without a container, the form used inside HLS streaming segments and by some hardware encoders; most consumer files wrap the same codec in an M4A/MP4 container instead, which we provide separately.
AAC is the successor to MP3 and the default audio codec of MP4 video, YouTube, Apple Music and every iPhone. Raw .aac files are a good test of players that assume every AAC comes in an MP4 box — several browsers handle ADTS inconsistently.
Download sample AAC files
| File | Details | Size | Download |
|---|---|---|---|
sample-audio-15s-128kbps.aac | 15 s · AAC · 131 kbps · 44.1 kHz · stereo | 247 KB | |
sample-audio-60s-128kbps.aac | 1 min · AAC · 131 kbps · 44.1 kHz · stereo | 989 KB |
Need one of every audio format? Download the audio sample pack (1.7 MB, one small file of every audio format (9 files)).
Use these files from the command line or CI
Every URL is stable and CORS-open. Pin the SHA-256 in your test and you will know the moment a fixture changes.
# Download one file curl -O https://pnb-website-bucket.s3.us-east-2.amazonaws.com/samples/audio/aac/sample-audio-15s-128kbps.aac # Verify it (SHA-256 is listed for every file above) shasum -a 256 sample-audio-15s-128kbps.aac # Machine-readable index of every sample file curl https://pnb-website-bucket.s3.us-east-2.amazonaws.com/samples/index.json | jq '.files[] | select(.format=="aac")'
AAC format at a glance
| Full name | Advanced Audio Coding (raw ADTS stream) |
|---|---|
| Extensions | .aac |
| MIME type | audio/aac |
| Standard | MPEG-2 Part 7 (1997) / MPEG-4 Part 3 |
| Profile | AAC-LC, 128 kbps stereo |
| Container | None — ADTS frame headers |
| Magic bytes | FF F1 or FF F9 (ADTS sync) |
What people test with sample AAC files
- HLS and streaming pipelines
- Player support for raw ADTS versus MP4-wrapped AAC
- Remuxing .aac into .m4a without re-encoding
Frequently asked questions
What is the difference between .aac and .m4a?
Same codec, different packaging. A .aac file is a bare ADTS stream; a .m4a is AAC inside an MP4 container with metadata, seeking tables and tags. M4A is what you want for distribution; ADTS is what streaming systems chop into segments.
Are these AAC files safe to download?
Yes. Every file is generated by our own open script from scratch — nothing is scraped or user-uploaded — and contains no scripts, macros or executables. The SHA-256 of each file is published on this page so you can verify what you received.
Can I use the sample AAC files commercially?
Yes. They are free for any purpose, including commercial products, test suites, demos and redistribution, with no attribution required. There is nothing to license and no one to ask.
Can I hotlink these files or use them in CI?
Yes. Every link is a stable direct URL over HTTPS with Access-Control-Allow-Origin: * and long cache headers, so curl, wget, fetch() and test runners can pull them directly. A JSON index of every file is linked from each page (see the command-line section).
Related sample files
Testing a file pipeline? We build them.
Uploads, conversions, previews, document processing and media workflows are the kind of production systems Pine & Birch designs and runs for clients — which is why we needed these files in the first place.
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