Stereo downmix EVS - Quality improvements for PHA mode.
Basic info
Description
The quality of the stereo downmix EVS in PHA mode can be improved. The identified corrections are : Change the filter taps resolution (Q31->Q30), improve the precisions for the IR window, for the ILD & IPD smoothing in sub-bands, for the ISD counters and for ICCr.
The corrections are proposed (by Orange) in the related branch.
For example : With testv/spectral_test_2ch_48kHz @128kb/s, the improvements are :
- MAX_ABS_DIFF : 6389 -> 3299 (-3090)
- SSNR : 20,82 -> 25,54 (+4,75) With testv/stvST16c @128kb/s, the improvements are :
- MAX_ABS_DIFF : 13522 -> 3526 (-9996)
- SSNR : 31,05 -> 33,85 (+2,8)
Ways to reproduce
The way to call the stereo downmix EVS is (for example) :
./IVAS_cod -stereo_dmx_evs 128000 48 testv/spectral_test_2ch_48kHz.wav bit
./IVAS_dec 48 bit spectral_test_2ch_48kHz_128000_48-48.wav