I am using the HIDAPI with Windows 8.1 to read out an audio stream from a HID device. This stream sends ADPCM data consisting of 259 bytes, where the first 12 packages are 20 bytes large, and the 13th is 19 bytes. The problem is that HIDAPI always give me 20 bytes (+1 byte report ID) and never 19 bytes. The audio part of HID is not supported natively under Windows, but is working for linux with some third party libraries, and catching the HID data directly in Ubuntu gives the correct data length. How can I fix this?
Edit: I see that when setting up the hid_device*, the call for dev->input_report_length = caps.InputReportByteLength; is set to 21 at the very beginning, thus making it impossible to change over time. Still, my device sends only 19 (20) bytes of data every 13 packet. Can this be changed dynamically during runtime?