ENVY24HT_PLAY_BUFUNIT
unit = ENVY24HT_PLAY_BUFUNIT / 4;
bsize = ch->blk * 4 / ENVY24HT_PLAY_BUFUNIT;
ch->blk *= ENVY24HT_PLAY_BUFUNIT / 4;
bsize = ch->blk * 4 / ENVY24HT_PLAY_BUFUNIT;
sc->psize = ENVY24HT_PLAY_BUFUNIT * ENVY24HT_SAMPLE_NUM;