That is because the HDV codec only supports 384kbit of mpeg-1 layer 2 audio. Unfortunately there is no way of making a HDV master with linear audio. This is in my mind one of the worst flaws of the HDV codec. Audio sweetening is made extremely harder because of material originating from HDV. But, it’s still a great DV camera with a true 16:9 chip and linear audio when DV is selected…