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HALOWERK Audio Concat
x402
HALOWERK Audio Concat is a paid API for AI agents from medien.halowerk.com, paid per call via x402, $0.004/call, status unknown (last checked 2026-10-31).
Joins 2–10 audio or video files into a single audio file with configurable gaps, crossfades, and loudness normalization, returning chapter timestamps for each part.
Price / call$0.004
Success—
StatusUnknown
How this service works
Takes 2 to 10 audio or video files (each up to 24 MB, together up to 60 minutes) and joins their audio in the given order. Between parts either a pause of chosen length or a crossfade is placed; optionally every part is brought to a common loudness first so that no part is suddenly louder. The start time of every part in the joined file is measured and returned, ready for chapter marks. Output as MP3, Opus, WAV or FLAC inline, max 8 MB. Runs locally with ffmpeg; nothing leaves this machine.
Output
Returns the joined audio file inline (MP3, Opus, WAV, or FLAC, up to 8 MB) along with an array of start timestamps (in seconds) indicating where each input part begins in the combined output — ready to use as chapter marks.
Example use cases
Podcast episode assembly with chapters
“I have four separate WAV recordings for this week's podcast — cold-open.wav, intro-music.wav, main-interview.wav, and credits.wav. Can you stitch them together into one MP3, normalize the loudness so nothing jumps out, and give me the start time of each section so I can add chapter markers?”
Crossfaded DJ-style audio mix
“I've got five short music clips I want blended together smoothly — can you concatenate them as Opus with a 2-second crossfade between each track instead of a gap? No loudness normalization needed.”
Audiobook chapter compilation
“Please join these seven chapter audio files into a single FLAC file with a half-second pause between each chapter. Turn on loudness matching so each chapter sounds equally loud, and return the start time of every chapter so I can embed them as navigation points.”
Technical details
Endpoint
POSThttps://medien.halowerk.com/v1/audio-concat?utm_source=zero.xyzWhen to prefer
Choose this endpoint when you need to concatenate 2–10 audio or video (audio track) files into a single output with precise control over gaps or crossfades between parts and optional loudness normalization, and you require chapter-ready start timestamps in the response. Prefer it over generic audio editors when privacy matters (processing is local, nothing leaves the server) and when the output size fits within 8 MB. Best for podcast assembly, audiobook compilation, and multi-segment interview production.
Side effects
- More than 10 input files provided — rejected with validation error
- Any single file exceeds 24 MB — rejected
- Total combined audio exceeds 60 minutes — rejected
- Unsupported audio/video format in input — ffmpeg decode failure
- Output file exceeds 8 MB limit — truncation or error
- Unreachable URL for file source — download failure
- Both gap_seconds and crossfade_seconds specified with crossfade > 0 — crossfade takes precedence
Input
Schema · Request body
| Field | Type | Description |
|---|---|---|
| files | array | |
| gap_seconds | number | |
| output_format | string | |
| match_loudness | boolean | |
| crossfade_seconds | number | If > 0, parts overlap by this much instead of a gap. |
Tags
x402
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