I use a usb speakerphone to play audio on X20, but it can not output audio correctly。 The speakerphone output format is 48000 sample and 16bit stereo。 I use the USB protocol Analyzer to get the usb data, all data are crc incorrect, it should send 192 bytes per 1ms(one audio sample ), but in fact only 185 bytes or 186bytes sent.
And when I modified sending data length per ms, I got that the usb driver can send 188 bytes per ms extermely 。When it send data length bigger than 188 bytes, the audio data speakerphone received every ms can be lost , that is , data length received shorter than 188bytes per ms.
Can somebody help me ,thanks very much .
You could take a look at tinyplay (which I think is part of tinyalsa). If you build or enable that then you get lower level access to the sound card (from root prompt rather than using whole Android stack).
That might help you figure out where to debug.