JBM and DTX interaction not as expected

When running

IVAS_cod -stereo 32000 48 scripts/testv/stvST48n.wav bit
IVAS_dec stereo 48 bit out.wav
networkSimulator_g192 scripts/dly_error_profiles/dly_error_profile_0.dat bit bit_netsim no_dtx.netsimtrace 1 0
IVAS_dec -tracefile no_dtx.dectrace -voip stereo 48 bit_netsim out_jbm.wav

out.wav and out_jbm.wav are bitexact, except for a constant delay of 60ms in out_jbm.wav (out_jbm.wav is 60 ms longer). This is expected behaviour.

However, when running

IVAS_cod -dtx -stereo 32000 48 scripts/testv/stvST48n.wav bit_dtx
IVAS_dec stereo 48 bit_dtx out_dtx.wav
networkSimulator_g192 scripts/dly_error_profiles/dly_error_profile_0.dat bit_dtx bit_dtx_netsim dtx.netsimtrace 1 0
IVAS_dec -tracefile dtx.dectrace -voip stereo 48 bit_dtx_netsim out_dtx_jbm.wav

this is not the case analogously for out_dtx.wav and out_dtx_jbm.wav. Instead, out_dtx_jbm.wav is 40ms shorter then out_dtx.wav. Also, if one strips away 60ms at the start of out_dtx_jbm.wav and 100ms at the end of out_dtx.wav (to simply have the same length), the signals are not bitexact as expected.

The signal ends with a near-silence period, so the different length could be caused by having NO_DATA frames at the end of the bitstream.

Tracefiles:

Edited Jun 12, 2024 by Jan Kiene