Convert M4R to SPX

Turn M4R recordings into Speex. Re-encoded as Speex speech coding in an Ogg file at 8, 16 or 32 kHz in mono or stereo, unless audio.sample_rate or audio.channels say otherwise, which loses a little more than the AAC already did.

Converted in an isolated sandbox on our serversDeleted after 24 hours

Drop M4R files on the dialor turn it to pick what to do

M4R and SPX

From

iPhone Ringtone

AAC ringtones for iPhone. The same container as M4A; the phone only accepts clips under 40 seconds.

Extensions: .m4r
MIME type: audio/mp4
Kind: Audio

To

Speex

Speex speech audio in an Ogg container, the predecessor of Opus.

Extensions: .spx
MIME type: audio/x-speex
Kind: Audio

Options for M4R to SPX

audio.channels: Number of audio channels. 1 is mono, 2 is stereo.
audio.denoise: Reduce steady background noise.
audio.normalize: Normalize loudness to -16 LUFS as streaming services do.
audio.sample_rate: Audio sample rate in Hz.
speed: Playback speed multiplier. 2 plays twice as fast.
trim_end: Second at which the audio or video stops.
trim_start: Seconds to cut from the start of audio or video.