Audio

Endpoints for converting and compressing audio files using FFmpeg.

Convert

$0.0003per MB$0.01 min

POST /audio/convert

Convert audio files between 15 formats with control over codec, bitrate, sample rate, channels, volume, normalization, trimming, and metadata.

Supported formats: AAC, AC3, AIFF, AMR, AU, CAF, FLAC, M4A, M4B, MP3, OGA, VOC, WAV, WEBA, WMA.

Parameters

Name	Type	Default	Description
`inputFormat`	`aac` \| `ac3` \| `aiff` \| `amr` \| `au` \| `caf` \| `dss` \| `flac` \| `m4a` \| `m4b` \| `mp3` \| `oga` \| `voc` \| `wav` \| `weba` \| `wma`	—	Override MIME type detection for formats browsers may not recognize.
`targetFormat`	`aac` \| `ac3` \| `aiff` \| `amr` \| `au` \| `caf` \| `flac` \| `m4a` \| `m4b` \| `mp3` \| `oga` \| `voc` \| `wav` \| `weba` \| `wma`	`mp3`	Output format.
`codec`	`auto` \| `aac` \| `mp3` \| `opus` \| `vorbis` \| `flac` \| `alac` \| `pcm_s16le` \| `pcm_s24le` \| `pcm_s32le` \| `pcm_s16be` \| `ac3` \| `wmav2` \| `amr_nb` \| `copy`	`auto`	Audio codec. auto picks best for format, copy remuxes without re-encoding.
`bitrate`	string	—	Target bitrate (e.g. 128k, 320k).
`vbrQuality`	number	—	MP3 VBR quality 0-9 (0 = best). Requires mp3Mode=vbr.
`sampleRate`	number	—	Sample rate in Hz (e.g. 44100, 48000). Omit to preserve source.
`channels`	number	—	1 (mono) or 2 (stereo). Omit to preserve source.
`bitDepth`	`8` \| `16` \| `24` \| `32`	—	PCM bit depth. Ignored for compressed codecs.
`startTime`	string	—	Trim start (e.g. 00:01:30 or 90).
`endTime`	string	—	Trim end position.
`duration`	string	—	Max duration from startTime.
`volume`	string	—	Volume adjustment (e.g. 1.5, -3dB).
`normalize`	`true` \| `false`	`false`	Apply EBU R128 loudness normalization.
`stripMetadata`	`true` \| `false`	`false`	Remove all metadata tags.
`title`	string	—	Set title tag.
`artist`	string	—	Set artist tag.
`album`	string	—	Set album tag.
`genre`	string	—	Set genre tag.
`year`	string	—	Set year tag.
`trackNumber`	string	—	Set track number tag.
`aacProfile`	`aac_low` \| `aac_he` \| `aac_he_v2`	—	AAC profile. Only applies to AAC output.
`flacCompression`	number	—	FLAC compression level 0-12.
`mp3Mode`	`cbr` \| `vbr`	`cbr`	MP3 encoding mode. CBR uses bitrate, VBR uses vbrQuality.

Example


tempo request -X POST https://api.fylor.com/audio/convert \
  -F "file=@input.wav" \
  -F "targetFormat=mp3" \
  -F "bitrate=320k" \
  -o output.mp3

Example: Convert to FLAC (lossless)


tempo request -X POST https://api.fylor.com/audio/convert \
  -F "file=@input.mp3" \
  -F "targetFormat=flac" \
  -F "flacCompression=8" \
  -o output.flac

Limits

Max file size: 500 MB

Compress

$0.0003per MB$0.01 min

POST /audio/compress

Reduce audio file sizes while keeping the same format. Lossy formats (MP3, AAC, etc.) get lower bitrate encoding. Lossless formats (WAV, FLAC, AIFF, etc.) get reduced bit depth and/or sample rate. If compression doesn’t reduce the file size, the original is returned unchanged.

Supported formats: AAC, AC3, AIF, AIFC, AIFF, AMR, AU, CAF, FLAC, M4A, M4B, MP3, OGA, VOC, WAV, WEBA, WMA.

Parameters

Name	Type	Default	Description
`quality`	`light` \| `medium` \| `heavy` \| `extreme`	`medium`	Compression preset. Light: 192kbps/16-bit. Medium: 128kbps/16-bit/44.1kHz cap. Heavy: 96kbps/16-bit/22kHz cap. Extreme: 64kbps/8-bit/22kHz cap.
`bitrate`	string	—	Override bitrate for lossy formats (e.g. 128k, 256k).
`sampleRate`	number	—	Override output sample rate in Hz.
`channels`	`1` \| `2`	—	Force mono or stereo. Omit to preserve source.
`bitDepth`	`8` \| `16` \| `24` \| `32`	—	Override bit depth for lossless/PCM formats.
`normalize`	`true` \| `false`	`false`	Apply EBU R128 loudness normalization before encoding.
`stripMetadata`	`true` \| `false`	`true`	Remove ID3, Vorbis comments, and other metadata tags.
`stripArtwork`	`true` \| `false`	`true`	Remove embedded cover art (can save 500KB+).

Example


tempo request -X POST https://api.fylor.com/audio/compress \
  -F "file=@podcast.mp3" \
  -F "quality=heavy" \
  -o compressed.mp3

Example: Compress WAV with normalization


tempo request -X POST https://api.fylor.com/audio/compress \
  -F "file=@recording.wav" \
  -F "quality=medium" \
  -F "normalize=true" \
  -o compressed.wav

Limits

Max file size: 500 MB

Response Headers

Every response includes:

Header	Description
`X-Request-Id`	Unique request identifier (UUID). Use this for support issues or when submitting feedback.

Two-Step Upload (for AI Agents)

If your client can only send JSON (e.g., AgentCash), use the two-step flow instead of direct multipart upload.

Step 1: Pay and create a job

Audio endpoints use per-MB pricing, so you must include fileSizeBytes in the JSON body.


curl -X POST https://api.fylor.app/audio/convert \
  -H "Content-Type: application/json" \
  -H "Authorization: Payment <token>" \
  -d '{"targetFormat": "mp3", "bitrate": "320k", "fileSizeBytes": 10485760}'

Response:


{
  "jobId": "550e8400-e29b-41d4-a716-446655440000",
  "uploadUrl": "/jobs/550e8400-e29b-41d4-a716-446655440000/upload",
  "expiresIn": 300
}

Step 2: Upload the file


curl -X POST https://api.fylor.app/jobs/550e8400-e29b-41d4-a716-446655440000/upload \
  -F "file=@song.flac" \
  -o song.mp3

Notes

Jobs expire after 5 minutes and are single-use.
fileSizeBytes must be within 10% of the actual file size.
Both audio endpoints support this flow: /audio/convert, /audio/compress.