Higher MLD with BASOP encoder for rate switching LTV MASA case

Basic info

• Float reference:
  • Encoder (float): b63c033f
  • Decoder (float): b63c033f
• Fixed point:
  • Encoder (fixed): a6ac7971
  • Decoder (fixed): a6ac7971

Bug description

There is significantly higher MLD score observed when BASOP encoder is used for a set of various rate switching cases of LTV MASA. The specific example given has the highest value (about 24.8 MLD) and does not include any other complex modes in the operation. Notably, same operation with combination of float encoder to BASOP decoder has MLD score of only 1.3 so decoder is not affecting things that much here. As this is EXT output, the values are based on transport channels which is core coding.

When listening to the sample, however, the effect is not so critical.

Ways to reproduce

Use command line with this rate switching pattern generic_start_128k_20frames.bin

IVAS_cod -masa 2 ltv48_MASA2TC.met -max_band swb generic_start_128k_20frames.bin 48 ltv48_MASA2TC.wav test_0070.bs
IVAS_dec EXT 48 test_0070.bs 0070_ltv48_MASA2TC.wav_generic_start_128k_20frames_48-48___EXT.wav