What does it cost to convert Ogg to WAV?

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

How large can the Ogg 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 / Ogg to WAV

Convert Ogg to WAV

To convert Ogg to WAV, send one POST to /v1/audio-convert with the Ogg 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 Ogg 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-clip.ogg",
  "to": "wav"
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "source_url": "https://grist.tools/samples/av/pair-clip.ogg",
  "bytes": 12553,
  "source_container": "ogg",
  "format": "wav",
  "bitrate_kbps": null,
  "sample_rate": null,
  "audio_bytes": 64044,
  "audio_base64": "UklGRiT6AABXQVZFZm10IBAAAAABAAEAQB8AAIA+AAACABAAZGF0YQD6AAAA0ADc..."
}

Source file: av/pair-clip.ogg, 12.3 KB (12,553 bytes). 4 s Ogg file: a 64x36 Theora video stream at 1 fps (a slate field with a small amber square moving right) and a mono 8 kHz FLAC audio track of two 500 Hz triangle beeps, both muxed by ffmpeg, plus a two-cue OGM text subtitle stream added by the generator. The recorded run returned 62.5 KB (64,044 bytes) of WAV, 5.1 times the source size, with the source read as the ogg container. Decoded, the WAV in audio_base64 opens with 52 49 46 46 24 FA 00 00 57 41 56 45 (ASCII RIFF and WAVE). Recorded with ffmpeg 8.1.2.

In the sample itself, 16 Ogg pages carry 3 logical streams: Theora 3.2.1 video of 64 by 36 pixels at 1 frame per second (serial 0), FLAC 1.0 mapping audio at 8,000 Hz with 1 channel (serial 1) and an OGM text stream (serial 2). The end-of-stream pages hold granule positions 2,250 for serial 2, 67 for serial 0 and 32,000 for serial 1. In the returned WAV: the RIFF header counts 64,036 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 64,000 bytes of samples, 4 s at that rate.

03Format notes

Ogg as a source

An Ogg file opens with the capture pattern OggS, and the container can carry Vorbis, Opus or Theora streams. Grist sniffs that pattern and hands Ogg to three of the conversion services on these pages. Audio conversion decodes the first audio stream, leaving any Theora picture aside. A thumbnail request seeks before opening the input and decodes a single frame from the first video stream, discarding sound. Caption extraction maps a subtitle stream counted from zero among the subtitle streams and serialises it through ffmpeg. Because audio-convert writes its Opus output inside Ogg, a file produced by that service comes back as an Ogg source, not as a separate Opus format. Theora is a lossy video codec, so a frame taken from it carries compression noise into the thumbnail, unlike a clip whose video stream is itself stored losslessly.

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 Ogg to WAV?: $0.003 per call, paid in USDC on Base via x402.
How large can the Ogg 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.