Convert M4A to SPX

Turn M4A recordings into Speex. 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, and AAC audio loses a little more than it already had.

Converted in an isolated sandbox on our serversDeleted after 24 hours

Drop M4A files on the dialor turn it to pick what to do

M4A and SPX

From

M4A Audio

AAC audio in an MP4 container. What Apple Music and iTunes use.

Extensions: .m4a
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 M4A 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.