Originally Posted by xmguy
Mike just to let you know the Casio Commando 4G (on Verizon Wireless) works with the FM chip (Qualcomm MSM8960) in digital mode, using the Digital OneXL/S/Sony profile, also works with Digital Auto profile in Spirit. The phone is rooted and needs root. App WILL work unrooted but gives no audio, however RDS and signal meter displays. Maybe even Spirit 2 can work. This may be the only known Verizon phone to support digital FM chipset. Only current issue is with the stock app as well as Spirit is auto muting with low signal. Hope we can work on a fix when you return from your break.
MSM8960 is the SOC / System on Chip / CPU etc. Spirit doesn't care about the SOC, assuming it's ARM (don't support Intel any more) and assuming you don't have one of the broken versions of Spirit that won't run on older ARMv6 SOCs.
FM/BT/WiFi combo chip is Qualcomm WCN3660 and audio is Qualcomm WDC9310 or similar. These 2 chips are what Spirit needs to support a device.
Did you try many Audio Methods while unrooted ? Most likely to work is "Sony/QC Intent" which uses a Qualcomm defined Intent that their sample FM apps use.
If you're looking for "fun" you can try setting Digital-> Sample Rate to 44101. On these chips the default 44100 sample rate gets converted to 22050 and 44101 actually sets it to a real 44100.
If the audio gets weird, you have the problem that made me change it to 22050 in the first place. Sony Z didn't have this problem and could use 44101 = 44100.
Sometimes the problem can be fixed, or results just changed, by setting AF-> AF Period to something other than the default 500. This changes the digital audio buffer size, and it can be changed while FM is running for immediate feedback.
The default AF Period of 500 turns into a buffer size of 320 bytes, which is 160 audio samples, or in stereo, 80 samples. Using multiples of 80 or 320 seems to work best.
Small buffer sizes can result in audio dropouts. Large sizes will result in a lot of audio delay; change the frequency and it takes a while for audio to catch up.
On every other audio chip, the default buffer size is 4096 bytes, which seems a good tradeoff.
At one time I tried sample rates of 48000 and 96000; I don't recall if that worked, but every device is supposed to support 44100, so that's the Spirit default. I think the Qualcomm audio chip was the only one I saw that could be changed from 44.1K, but the whole 22050 Hz and 320 byte hacks have kept me from being happy about this chip.