Very high MLD for 7_1_4, 160kbps, -26LKFS input, with deterministic packet loss pattern

Basic info

• Encoder (float): d18cbee3 (ivas-float-update)
• Decoder: 074e9116 (tag: 20241023_Ittiam_Decoder_Release_subjective_Testing)

Input format: 7_1_4

Input level: -26LKFS

Encoding bitrate: 16kbps

Decoding format: 7_1_4

Loss pattern: generated with following script

for l in range(1, 20, 3):
            losts += '!k' * (9 * l) + ' k' * l

Bug description

The fixed- and the floating-point decoded signal exhibit high MLD (59.24), low SSNR (18.29). Major waveform deviation across all channels. The worst deviation was observed in channel 4, where the fixed-point decoder produced two massive pulses, as illustrated in the follow plot.

Ways to reproduce

Supoprting files: https://dolby.box.com/s/4mpzjcv9u14dlqkrv2j36vgd6h6nmr55

./IVAS_cod -no_delay_cmp -mc 7_1_4 160000 48 in.wav bit
./IVAS_dec -no_delay_cmp 7_1_4 48 bit fx.wav
./IVAS_dec_ref -no_delay_cmp 7_1_4 48 bit fl.wav