High MLD decoding 7_1_4 bitstream, input signal level -16LKFS, bitrate 160kbps

Basic info

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

Bug description

The decoded signals produced the fixed- and the floating-point decoders demonstrated MLD at 15.29. The input signal was leveled at -16LKFS. Clipping was observed in at least one of the channels (channel 2) of the fixed-point output.

MLD at 15.290713

Cmp PCM Report
=====================
ref_file: am3ba1s07_7_1_4_-16_160000_CTX_fl_7_1_4.wav
cmp_file: am3ba1s07_7_1_4_-16_160000_CTX_fx_7_1_4.wav
960 (464640, 12) (464640, 12)
MAXIMUM ABS DIFF ==> 10356 at sample num 379651 (assuming 12 channels)
First diff found at sample num 393 in channel 11, frame 0 (assuming 12 channels, 48000 sampling rate)
MLD: 15.290713
Channel 0 ODG: -0.415
Channel 1 ODG: -0.258
Channel 2 ODG: -0.2
Channel 3 ODG: -0.404
Channel 4 ODG: -0.295
Channel 5 ODG: -0.379
Channel 6 ODG: -0.546
Channel 7 ODG: -0.61
Channel 8 ODG: -0.26
Channel 9 ODG: -0.26
Channel 10 ODG: -0.248
Channel 11 ODG: -0.243
Non-BE - MAXIMUM ABS DIFF: 10356 - MLD: 15.290713 > 0 - Channel 1 SSNR: 42.99 - Channel 2 SSNR: 49.72 - Channel 3 SSNR: 53.13 - Channel 4 SSNR: 64.08 - Channel 5 SSNR: 40.53 - Channel 6 SSNR: 40.11 - Channel 7 SSNR: 37.27 - Channel 8 SSNR: 40.71 - Channel 9 SSNR: 43.65 - Channel 10 SSNR: 42.98 - Channel 11 SSNR: 44.94 - Channel 12 SSNR: 43.77 -  - Channel 0 ODG: -0.415 - Channel 1 ODG: -0.258 - Channel 2 ODG: -0.2 - Channel 3 ODG: -0.404 - Channel 4 ODG: -0.295 - Channel 5 ODG: -0.379 - Channel 6 ODG: -0.546 - Channel 7 ODG: -0.61 - Channel 8 ODG: -0.26 - Channel 9 ODG: -0.26 - Channel 10 ODG: -0.248 - Channel 11 ODG: -0.243

Following plots depicts channel 2 of the fixed- and the floating-point outputs.

Ways to reproduce

Supporting files: https://dolby.box.com/s/ak874k9exb9rgtbe6bsguvbdo2lkmyxg

./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