What does it cost to convert AIFF to WAV?

$0.003 per call, paid in USDC on Base via x402.

How large can the AIFF file be?

Up to 100 MB (104,857,600 bytes), and at most 60 min (3,600 s) of media. Past a limit the call answers too_large (413).

What happens if the conversion fails?

The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled.

catalogue / tools / Audio & video / AIFF to WAV

Convert AIFF to WAV

To convert AIFF to WAV, send one POST to /v1/audio-convert with the AIFF source and "to": "wav" in the body. Left out, "to" falls back to its default "mp3", so a WAV request has to send it. Each call costs $0.003 in USDC on Base via x402, with no account and no API key. The source file can be up to 100 MB and 60 min (3,600 s) long.

Endpoint: POST /v1/audio-convert
Price: $0.003 per call
Service: audio-convert
Docs: /docs/audio-convert

01Limits

Limit	Value
Largest source file	100 MB (104,857,600 bytes)
Longest input	60 min (3,600 s)
Timeout	94 s
Source formats	AIFF, AVI, FLAC, MKV, MP3, MP4, Ogg, WAV
Output formats	AAC, FLAC, MP3, Opus, WAV

02Example

A real AIFF to WAV run of audio-convert.

Request

POST /v1/audio-convert
content-type: application/json
payment-signature: <base64 x402 payload>

{
  "url": "https://grist.tools/samples/av/pair-tone.aiff",
  "to": "wav"
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "source_url": "https://grist.tools/samples/av/pair-tone.aiff",
  "bytes": 48054,
  "source_container": "aiff",
  "format": "wav",
  "bitrate_kbps": null,
  "sample_rate": null,
  "audio_bytes": 48044,
  "audio_base64": "UklGRqS7AABXQVZFZm10IBAAAAABAAEAQB8AAIA+AAACABAAZGF0YYC7AAAA4ADo..."
}

Source file: av/pair-tone.aiff, 46.9 KB (48,054 bytes). 3 s mono 8 kHz 16-bit PCM AIFF file written directly by the generator: three 0.5 s 500 Hz triangle beeps at rising level, each followed by 0.5 s of silence. The recorded run returned 46.9 KB (48,044 bytes) of WAV, 100% of the source size, with the source read as the aiff container. Decoded, the WAV in audio_base64 opens with 52 49 46 46 A4 BB 00 00 57 41 56 45 (ASCII RIFF and WAVE). Recorded with ffmpeg 8.1.2.

In the sample itself, the FORM container is of type AIFF; the COMM chunk declares 1 channel, 24,000 sample frames of 16 bits and a rate of 8,000 Hz stored as an 80-bit extended float, 3 s; the SSND chunk holds 48,008 bytes, big-endian samples behind an 8-byte offset and block size header. In the returned WAV: the RIFF header counts 48,036 bytes after itself, and the fmt chunk, in its own field order, declares audio format 1 (integer PCM), 1 channel, 8,000 Hz, 16,000 bytes per second, a block align of 2 bytes and 16 bits per sample. The data chunk right after it holds 48,000 bytes of samples, 3 s at that rate.

03Format notes

AIFF as a source

AIFF files start with the IFF marker FORM, and Grist also requires the form type at byte eight to read AIFF or AIFC, the variant that allows compressed audio. Classic AIFF stores its PCM samples big-endian, the opposite byte order to WAV. The format is audio only, so video-thumbnail and subtitle-extract turn it away as a container without a picture or caption stream, and audio-convert is its single reader. That service measures the first audio stream's duration, maps only that stream, and strips metadata and chapters before encoding. AIFF is absent from audio-convert's destination enum, so it can be read here but not written. Converting to WAV rewrites the samples as little-endian PCM through the pinned pcm_s16le codec, which changes byte order without altering the sampled values of a sixteen-bit source.

WAV as a target

WAV output is written with the pinned pcm_s16le codec, so every result holds signed little-endian PCM regardless of the source encoding. The WAV muxer fills in its RIFF chunk sizes when the file closes, so Grist points ffmpeg at a seekable temporary file inside the per-call directory and reads it back, rather than streaming to a pipe. A bitrate_kbps value is rejected for this lossless destination instead of being ignored. The optional sample_rate must come from the service's closed set; left out, ffmpeg chooses, normally keeping the source rate. Only the first audio stream is mapped, with video, metadata and chapters removed, and bit-exact flags make the bytes reproducible for the pinned ffmpeg. PCM from a lossy source contains the decoded samples at full size, without restoring detail the earlier codec discarded.

04Errors

Code	HTTP
`invalid_input`	`400`
`blocked_target`	`403`
`unreachable_target`	`424`
`upstream_timeout`	`424`
`unsupported_content_type`	`415`
`too_large`	`413`
`unprocessable`	`422`
`internal`	`500`

When each is raised, and what it means for payment: /docs/audio-convert.

05Questions

What does it cost to convert AIFF to WAV?: $0.003 per call, paid in USDC on Base via x402.
How large can the AIFF file be?: Up to 100 MB (104,857,600 bytes), and at most 60 min (3,600 s) of media. Past a limit the call answers too_large (413).
What happens if the conversion fails?: The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled.