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HSP/HFP for calls is very standard; A2DP isn't suitable for calls since it's unidirectional. HFP 1.6 supports wide band (16khz) speech with the mSBC codec, whic
by dlubarov 8y ago
HSP/HFP for calls is very standard; A2DP isn't suitable for calls since it's unidirectional. HFP 1.6 supports wide band (16khz) speech with the mSBC codec, which is a big improvement, but adoption has been very slow.
E.g. in Android, I think Oreo finally added some HFP 1.6 support, and 16kz SCO output should be theoretically possible (I wasn't able to get it to work). But for some reason, 8khz SCO input remains explicitly unsupported, as per the AudioManager doc:
> "The following restrictions apply on [SCO] input streams: [...] the sampling must be 8kHz"
From what I've seen, most bluetooth devices and cellular providers don't seem to support 16khz speech either. At this rate, it seems like most of us won't enjoy wide band bluetooth calls until 2030 or so.