Module analysis 

Port of libopus 1.3.1 src/analysis.c + src/mlp.c (float build): the tonality/music/bandwidth analysis that drives mode selection, bandwidth detection, VBR boosts and prefilter damping in the reference encoder.

Faithful line-for-line port. The MLP (dense 25→32, GRU →24, dense →2) uses the shipped int8 weight tables in crate::analysis_data. The FFT is the CELT mode’s N=480 kiss-FFT (same twiddles/bitrev as the reference; the forward scale 1/N is applied in the input copy, as C’s opus_fft does).

Structs

AnalysisInfo

celt.h AnalysisInfo (float build).

TonalityAnalysisState

Constants

ANALYSIS_BUF_SIZE

ANALYSIS_COUNT_MAX

DETECT_SIZE

LEAK_BANDS

NB_FRAMES

NB_TBANDS

Functions

run_analysis

run_analysis: feed the frame through 20 ms analysis steps, then read the interpolated info for this frame.

tonality_get_info

tonality_get_info: interpolate the ring of per-20ms analyses into one AnalysisInfo for a frame of len samples (encoder rate), applying the music/speech hysteresis thresholds (music_prob_min/max).