I found a temporary/permanent solution. Switching of the exclusive mode stream in windows advanced audio setting seems to do the trick and now it honors my set_max/get_max requests. Some other application was possibly messing with the volume slider values.
On 8/29/2017 1:41 PM, Akshaykeerti Sharma wrote:
Let me start by introducing myself, I am a embedded software engineer and have been trying to brave my way through the USB-Audio 1.0 class.
We designed a USB speaker using the USB audio class 1.0 spec and it seems to work pretty great till you set the bmaControls to allow the hardware to control the volume directly.
-- I am not sure if the windows audio driver is supposed to honor my request of SET_MAX/SET_MIN? I have it set to -127 to 128db and the scaling is absolutely confusing. Windows 10 returns to me a value between -60db to +60db whilst windows 7 returns a value between 60db-127db.
-- Setting the SET_MAX/SET_MIN to a custom value of say 0db - 1db (0-255) essentially locks the values at 0- 255 results in the output value scale being locked down to 0-255 but the windows volume slider scale still stuck at the defaults mentioned above.
--Now what I would desire(not sure if it is possible) is to have windows return to me a value of 0-255 or 0-100 without writing a custom driver and using the standard USB audio drivers. The second thing I would like to know is that is it possible to have consistent values being outputted from the volume slider across windows7 to windows10.
Here is a text file of the values the slider was giving me <https://pastebin.com/4j9MK90c>. On a side note, the usb-drivers seem to honor the bass/mid/treble sliders Set_Max/Set_Min I was using to debug some gains on the hardware.
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