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Energy issues (burst and attenuation) in MDCT-stereo @48kbps

Basic info

  • Float reference:
  • Fixed point:

Bug description

For selection item dp03a1s06 there are various issues observed. There is 5 ms attenuation for frame at 5.880 s, it seams like a TCX5 issue as can be seen here:

Screenshot_2025-01-22_at_10.43.26

and then there is strange energy burst throughout a whole frame at timestamp 6.260 s

Screenshot_2025-01-22_at_10.47.05

the float equivalent for comparison:

Screenshot_2025-01-22_at_10.48.12

It should be noted that there is bandwidth detection issue happening for float for a few frames at timestamp 2.660. This is reported in float repository with issue ivas-codec-pc/ivas-codec#1257 . Nevertheless, independent issues in BASOP should be checked.

The attenuation issue has been observed for yet another item, namely am1aa1s12 for timestamp 0.940 sec. Again the duration of the "gap" is 5ms which seems to be some sort of TCX5 issue.

Screenshot_2025-01-22_at_13.51.54

and float for reference

Screenshot_2025-01-22_at_13.52.02

It should be noted that differences throughout the two signals is rather large when looking at the waveforms/spectrograms

Ways to reproduce

Box folder: ...\Box_EXTERNAL_IVAS_BASOP_VERIFICATION\issues\issue-1208

./IVAS_cod -stereo -max_band FB 48000 48 dp03a1s06_48.wav out.192
./IVAS_dec stereo 48 out.192 dp03a1s06.dec.wav

./IVAS_cod -stereo -max_band FB 64000 48 am1aa1s12_48.wav out.192
./IVAS_dec stereo 48 out.192 am1aa1s12.dec.wav
Edited by fotopoulou