Recommendation for voicemail format?

My voicemail.conf currently has: format=wav49|gsm|wav.

I’m inclined to change this setting to format=wav but wonder if email-attached voicemails would be easy to listen on most platforms (Windows, MacOS, Linux, Android, iOS).

What would you recommend ?
Thoughts ?

Best regards

mp3 seems to be the most common format supported on most of the platforms.
What I had done in past is to use mailcmd option of voicemail.conf to convert wav to mp3 to be sent as an attachment in the email.

MP3 is a poor engineering choice, at least with default parameters, as it is over-engineered fro the actual quality of phone audio.

.wav with a gsm payload (= wav49 or WAV in Asterisk), will produce the smallest files for a universally supported format. Note that the .wav49 extension will not be recognized on windows, but it will be recognized with .WAV (or .wav).

Asterisk .wav will have the most universal support.

(It is possible to encode MP3 at lower bit rates than GSM, but I don’t know how many devices can handle such low rates, or how the quality compares. I would expect GSM to be better for speech than very low bit rate MP3. The default bit rate should produce file sizes similar to Asterisk .wav, with no quality improvement, and a lot of CPU processing.)

Agree as it is compressed format but OP was asking for “Easy to listen on most platforms” and I was talking about my experience of past projects where most of the clients wanted to have mp3 as an email attachment (because of smaller size and support to play on most of the platforms).


I don’t have any iOS or macOS device to test with so testimonies like this are very valuable.

@satish4asterisk: Converting audio files before sending them out is a smart advice I never thought of before. Thanks for mentioning this.

@david551: classical .wav format seems universally supported: maybe I’ll try with it first before trying something else (MP3 ?) if something goes wrong.

Thanks for answering.

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