EVS float and BASOP have different thresholds for DTX high-rate activation
Follow up to sa4/audio/ivas-basop#1226 (closed)
EVS has a conservative approach to activating DTX for bit rates above 24.4 kbps, such that DTX is only used for low level signals. The condition is however different for EVS float and EVS BASOP.
For float, the condition is
st->lp_noise < 15while the corresponding condition in BASOP is
LT_16(st_fx->lp_noise_fx, 1280)where 1280 is 5 is Q8.
The EVS BASOP has a more conservative behaviour than float. In a 2 minute test signal consisting of a repeated speech utterance with pink noise at different relative speech levels added, this is the activity obtained for BASOP and float:
If the threshold in EVS float is changed to 5 to be aligned with the EVS BASOP, the activity in this test is nearly identical:
Edited by vaclav