BYTES_PER_SAMPLE_USB
(stream << 1) | (~(i / (cdev->n_streams * BYTES_PER_SAMPLE_USB)) & 1)
if (i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) == 0) {
if (iso->actual_length % (BYTES_PER_SAMPLE_USB * CHANNELS_PER_STREAM))
i % (cdev->n_streams * BYTES_PER_SAMPLE_USB) ==