opus-decoder 0.1.0

//! SILK tables used by stereo signaling and NLSF/LPC decode.

/// Maximum SILK LPC order.
pub(super) const MAX_LPC_ORDER: usize = 16;
/// Maximum number of SILK subframes.
pub(super) const MAX_NB_SUBFR: usize = 4;
/// Maximum SILK subframe length in samples.
pub(super) const MAX_SUB_FRAME_LENGTH: usize = 80;
/// Maximum SILK frame length in samples.
pub(super) const MAX_FRAME_LENGTH: usize = 320;
/// LTP filter order.
pub(super) const LTP_ORDER: usize = 5;
/// LTP memory in milliseconds.
pub(super) const LTP_MEM_LENGTH_MS: usize = 20;
/// Minimum pitch lag in milliseconds.
pub(super) const PITCH_EST_MIN_LAG_MS: i32 = 2;
/// Maximum pitch lag in milliseconds.
pub(super) const PITCH_EST_MAX_LAG_MS: i32 = 18;
/// Maximum number of stage-2 contour codebooks.
pub(super) const PE_NB_CBKS_STAGE2_EXT: usize = 11;
/// Maximum number of stage-3 contour codebooks.
pub(super) const PE_NB_CBKS_STAGE3_MAX: usize = 34;
/// Number of stage-3 contour codebooks for 10 ms.
pub(super) const PE_NB_CBKS_STAGE3_10MS: usize = 12;
/// Number of stage-2 contour codebooks for 10 ms.
pub(super) const PE_NB_CBKS_STAGE2_10MS: usize = 3;
/// Quantization level adjustment in Q10.
pub(super) const QUANT_LEVEL_ADJUST_Q10: i32 = 80;
/// Unvoiced low quantization offset in Q10.
pub(super) const OFFSET_UVL_Q10: i32 = 100;
/// Unvoiced high quantization offset in Q10.
pub(super) const OFFSET_UVH_Q10: i32 = 240;
/// Voiced low quantization offset in Q10.
pub(super) const OFFSET_VL_Q10: i32 = 32;
/// Voiced high quantization offset in Q10.
pub(super) const OFFSET_VH_Q10: i32 = 100;
/// Number of quantized gain levels.
pub(super) const N_LEVELS_QGAIN: i32 = 64;
/// Minimum gain delta index.
pub(super) const MIN_DELTA_GAIN_QUANT: i32 = -4;
/// Maximum gain delta index.
pub(super) const MAX_DELTA_GAIN_QUANT: i32 = 36;

/// Full SILK NLSF codebook descriptor used by NLSF reconstruction.
#[derive(Debug, Clone, Copy)]
pub(super) struct NlsfCodebook {
    /// LPC order for the codebook.
    pub order: usize,
    /// Residual quantization step size in Q16.
    pub quant_step_size_q16: i32,
    /// Stage-1 centroids in Q8.
    pub cb1_nlsf_q8: &'static [u8],
    /// Stage-1 weights in Q9.
    pub cb1_wght_q9: &'static [i16],
    /// Predictive residual coefficients in Q8.
    pub pred_q8: &'static [u8],
    /// Packed predictor/entropy selector map.
    pub ec_sel: &'static [u8],
    /// Minimum deltas used during stabilization in Q15.
    pub delta_min_q15: &'static [i16],
}

/// Joint iCDF for stereo predictor coarse index (`silk_stereo_pred_joint_iCDF`).
pub(super) const STEREO_PRED_JOINT_ICDF: [u8; 25] = [
    249, 247, 246, 245, 244, 234, 210, 202, 201, 200, 197, 174, 82, 59, 56, 55, 54, 46, 22, 12, 11,
    10, 9, 7, 0,
];

/// Uniform 3-way iCDF (`silk_uniform3_iCDF`).
pub(super) const UNIFORM3_ICDF: [u8; 3] = [171, 85, 0];

/// Uniform 5-way iCDF (`silk_uniform5_iCDF`).
pub(super) const UNIFORM5_ICDF: [u8; 5] = [205, 154, 102, 51, 0];

/// Mid-only stereo flag iCDF (`silk_stereo_only_code_mid_iCDF`).
pub(super) const STEREO_ONLY_CODE_MID_ICDF: [u8; 2] = [64, 0];

/// Stereo predictor dequantization table (`silk_stereo_pred_quant_Q13`).
pub(super) const STEREO_PRED_QUANT_Q13: [i32; 16] = [
    -13_732, -10_050, -8_266, -7_526, -6_500, -5_000, -2_950, -820, 820, 2_950, 5_000, 6_500,
    7_526, 8_266, 10_050, 13_732,
];

/// LBRR-flag iCDF for 2 internal SILK frames (`silk_LBRR_flags_2_iCDF`).
pub(super) const LBRR_FLAGS_2_ICDF: [u8; 3] = [203, 150, 0];

/// LBRR-flag iCDF for 3 internal SILK frames (`silk_LBRR_flags_3_iCDF`).
pub(super) const LBRR_FLAGS_3_ICDF: [u8; 7] = [215, 195, 166, 125, 110, 82, 0];

/// Return LBRR iCDF table for given internal frame count.
///
/// Params: `internal_frames` is number of 20 ms SILK-internal frames in one Opus frame.
/// Returns: table slice for 2/3-frame packets, or `None` for unsupported counts.
pub(super) fn lbrr_flags_icdf(internal_frames: usize) -> Option<&'static [u8]> {
    match internal_frames {
        2 => Some(&LBRR_FLAGS_2_ICDF),
        3 => Some(&LBRR_FLAGS_3_ICDF),
        _ => None,
    }
}

/// Piecewise-linear cosine approximation table in Q12.
pub(super) const LSF_COS_TAB: [i16; 129] = [
    8192, 8190, 8182, 8170, 8152, 8130, 8104, 8072, 8034, 7994, 7946, 7896, 7840, 7778, 7714, 7644,
    7568, 7490, 7406, 7318, 7226, 7128, 7026, 6922, 6812, 6698, 6580, 6458, 6332, 6204, 6070, 5934,
    5792, 5648, 5502, 5352, 5198, 5040, 4880, 4718, 4552, 4382, 4212, 4038, 3862, 3684, 3502, 3320,
    3136, 2948, 2760, 2570, 2378, 2186, 1990, 1794, 1598, 1400, 1202, 1002, 802, 602, 402, 202, 0,
    -202, -402, -602, -802, -1002, -1202, -1400, -1598, -1794, -1990, -2186, -2378, -2570, -2760,
    -2948, -3136, -3320, -3502, -3684, -3862, -4038, -4212, -4382, -4552, -4718, -4880, -5040,
    -5198, -5352, -5502, -5648, -5792, -5934, -6070, -6204, -6332, -6458, -6580, -6698, -6812,
    -6922, -7026, -7128, -7226, -7318, -7406, -7490, -7568, -7644, -7714, -7778, -7840, -7896,
    -7946, -7994, -8034, -8072, -8104, -8130, -8152, -8170, -8182, -8190, -8192,
];

const NLSF_CB1_NB_MB_Q8: [u8; 320] = [
    12, 35, 60, 83, 108, 132, 157, 180, 206, 228, 15, 32, 55, 77, 101, 125, 151, 175, 201, 225, 19,
    42, 66, 89, 114, 137, 162, 184, 209, 230, 12, 25, 50, 72, 97, 120, 147, 172, 200, 223, 26, 44,
    69, 90, 114, 135, 159, 180, 205, 225, 13, 22, 53, 80, 106, 130, 156, 180, 205, 228, 15, 25, 44,
    64, 90, 115, 142, 168, 196, 222, 19, 24, 62, 82, 100, 120, 145, 168, 190, 214, 22, 31, 50, 79,
    103, 120, 151, 170, 203, 227, 21, 29, 45, 65, 106, 124, 150, 171, 196, 224, 30, 49, 75, 97,
    121, 142, 165, 186, 209, 229, 19, 25, 52, 70, 93, 116, 143, 166, 192, 219, 26, 34, 62, 75, 97,
    118, 145, 167, 194, 217, 25, 33, 56, 70, 91, 113, 143, 165, 196, 223, 21, 34, 51, 72, 97, 117,
    145, 171, 196, 222, 20, 29, 50, 67, 90, 117, 144, 168, 197, 221, 22, 31, 48, 66, 95, 117, 146,
    168, 196, 222, 24, 33, 51, 77, 116, 134, 158, 180, 200, 224, 21, 28, 70, 87, 106, 124, 149,
    170, 194, 217, 26, 33, 53, 64, 83, 117, 152, 173, 204, 225, 27, 34, 65, 95, 108, 129, 155, 174,
    210, 225, 20, 26, 72, 99, 113, 131, 154, 176, 200, 219, 34, 43, 61, 78, 93, 114, 155, 177, 205,
    229, 23, 29, 54, 97, 124, 138, 163, 179, 209, 229, 30, 38, 56, 89, 118, 129, 158, 178, 200,
    231, 21, 29, 49, 63, 85, 111, 142, 163, 193, 222, 27, 48, 77, 103, 133, 158, 179, 196, 215,
    232, 29, 47, 74, 99, 124, 151, 176, 198, 220, 237, 33, 42, 61, 76, 93, 121, 155, 174, 207, 225,
    29, 53, 87, 112, 136, 154, 170, 188, 208, 227, 24, 30, 52, 84, 131, 150, 166, 186, 203, 229,
    37, 48, 64, 84, 104, 118, 156, 177, 201, 230,
];

const NLSF_CB1_WGHT_NB_MB_Q9: [i16; 320] = [
    2897, 2314, 2314, 2314, 2287, 2287, 2314, 2300, 2327, 2287, 2888, 2580, 2394, 2367, 2314, 2274,
    2274, 2274, 2274, 2194, 2487, 2340, 2340, 2314, 2314, 2314, 2340, 2340, 2367, 2354, 3216, 2766,
    2340, 2340, 2314, 2274, 2221, 2207, 2261, 2194, 2460, 2474, 2367, 2394, 2394, 2394, 2394, 2367,
    2407, 2314, 3479, 3056, 2127, 2207, 2274, 2274, 2274, 2287, 2314, 2261, 3282, 3141, 2580, 2394,
    2247, 2221, 2207, 2194, 2194, 2114, 4096, 3845, 2221, 2620, 2620, 2407, 2314, 2394, 2367, 2074,
    3178, 3244, 2367, 2221, 2553, 2434, 2340, 2314, 2167, 2221, 3338, 3488, 2726, 2194, 2261, 2460,
    2354, 2367, 2207, 2101, 2354, 2420, 2327, 2367, 2394, 2420, 2420, 2420, 2460, 2367, 3779, 3629,
    2434, 2527, 2367, 2274, 2274, 2300, 2207, 2048, 3254, 3225, 2713, 2846, 2447, 2327, 2300, 2300,
    2274, 2127, 3263, 3300, 2753, 2806, 2447, 2261, 2261, 2247, 2127, 2101, 2873, 2981, 2633, 2367,
    2407, 2354, 2194, 2247, 2247, 2114, 3225, 3197, 2633, 2580, 2274, 2181, 2247, 2221, 2221, 2141,
    3178, 3310, 2740, 2407, 2274, 2274, 2274, 2287, 2194, 2114, 3141, 3272, 2460, 2061, 2287, 2500,
    2367, 2487, 2434, 2181, 3507, 3282, 2314, 2700, 2647, 2474, 2367, 2394, 2340, 2127, 3423, 3535,
    3038, 3056, 2300, 1950, 2221, 2274, 2274, 2274, 3404, 3366, 2087, 2687, 2873, 2354, 2420, 2274,
    2474, 2540, 3760, 3488, 1950, 2660, 2897, 2527, 2394, 2367, 2460, 2261, 3028, 3272, 2740, 2888,
    2740, 2154, 2127, 2287, 2234, 2247, 3695, 3657, 2025, 1969, 2660, 2700, 2580, 2500, 2327, 2367,
    3207, 3413, 2354, 2074, 2888, 2888, 2340, 2487, 2247, 2167, 3338, 3366, 2846, 2780, 2327, 2154,
    2274, 2287, 2114, 2061, 2327, 2300, 2181, 2167, 2181, 2367, 2633, 2700, 2700, 2553, 2407, 2434,
    2221, 2261, 2221, 2221, 2340, 2420, 2607, 2700, 3038, 3244, 2806, 2888, 2474, 2074, 2300, 2314,
    2354, 2380, 2221, 2154, 2127, 2287, 2500, 2793, 2793, 2620, 2580, 2367, 3676, 3713, 2234, 1838,
    2181, 2753, 2726, 2673, 2513, 2207, 2793, 3160, 2726, 2553, 2846, 2513, 2181, 2394, 2221, 2181,
];

const NLSF_PRED_NB_MB_Q8: [u8; 18] = [
    179, 138, 140, 148, 151, 149, 153, 151, 163, 116, 67, 82, 59, 92, 72, 100, 89, 92,
];

const NLSF_DELTA_MIN_NB_MB_Q15: [i16; 11] = [250, 3, 6, 3, 3, 3, 4, 3, 3, 3, 461];

const NLSF_CB1_WB_Q8: [u8; 512] = [
    7, 23, 38, 54, 69, 85, 100, 116, 131, 147, 162, 178, 193, 208, 223, 239, 13, 25, 41, 55, 69,
    83, 98, 112, 127, 142, 157, 171, 187, 203, 220, 236, 15, 21, 34, 51, 61, 78, 92, 106, 126, 136,
    152, 167, 185, 205, 225, 240, 10, 21, 36, 50, 63, 79, 95, 110, 126, 141, 157, 173, 189, 205,
    221, 237, 17, 20, 37, 51, 59, 78, 89, 107, 123, 134, 150, 164, 184, 205, 224, 240, 10, 15, 32,
    51, 67, 81, 96, 112, 129, 142, 158, 173, 189, 204, 220, 236, 8, 21, 37, 51, 65, 79, 98, 113,
    126, 138, 155, 168, 179, 192, 209, 218, 12, 15, 34, 55, 63, 78, 87, 108, 118, 131, 148, 167,
    185, 203, 219, 236, 16, 19, 32, 36, 56, 79, 91, 108, 118, 136, 154, 171, 186, 204, 220, 237,
    11, 28, 43, 58, 74, 89, 105, 120, 135, 150, 165, 180, 196, 211, 226, 241, 6, 16, 33, 46, 60,
    75, 92, 107, 123, 137, 156, 169, 185, 199, 214, 225, 11, 19, 30, 44, 57, 74, 89, 105, 121, 135,
    152, 169, 186, 202, 218, 234, 12, 19, 29, 46, 57, 71, 88, 100, 120, 132, 148, 165, 182, 199,
    216, 233, 17, 23, 35, 46, 56, 77, 92, 106, 123, 134, 152, 167, 185, 204, 222, 237, 14, 17, 45,
    53, 63, 75, 89, 107, 115, 132, 151, 171, 188, 206, 221, 240, 9, 16, 29, 40, 56, 71, 88, 103,
    119, 137, 154, 171, 189, 205, 222, 237, 16, 19, 36, 48, 57, 76, 87, 105, 118, 132, 150, 167,
    185, 202, 218, 236, 12, 17, 29, 54, 71, 81, 94, 104, 126, 136, 149, 164, 182, 201, 221, 237,
    15, 28, 47, 62, 79, 97, 115, 129, 142, 155, 168, 180, 194, 208, 223, 238, 8, 14, 30, 45, 62,
    78, 94, 111, 127, 143, 159, 175, 192, 207, 223, 239, 17, 30, 49, 62, 79, 92, 107, 119, 132,
    145, 160, 174, 190, 204, 220, 235, 14, 19, 36, 45, 61, 76, 91, 108, 121, 138, 154, 172, 189,
    205, 222, 238, 12, 18, 31, 45, 60, 76, 91, 107, 123, 138, 154, 171, 187, 204, 221, 236, 13, 17,
    31, 43, 53, 70, 83, 103, 114, 131, 149, 167, 185, 203, 220, 237, 17, 22, 35, 42, 58, 78, 93,
    110, 125, 139, 155, 170, 188, 206, 224, 240, 8, 15, 34, 50, 67, 83, 99, 115, 131, 146, 162,
    178, 193, 209, 224, 239, 13, 16, 41, 66, 73, 86, 95, 111, 128, 137, 150, 163, 183, 206, 225,
    241, 17, 25, 37, 52, 63, 75, 92, 102, 119, 132, 144, 160, 175, 191, 212, 231, 19, 31, 49, 65,
    83, 100, 117, 133, 147, 161, 174, 187, 200, 213, 227, 242, 18, 31, 52, 68, 88, 103, 117, 126,
    138, 149, 163, 177, 192, 207, 223, 239, 16, 29, 47, 61, 76, 90, 106, 119, 133, 147, 161, 176,
    193, 209, 224, 240, 15, 21, 35, 50, 61, 73, 86, 97, 110, 119, 129, 141, 175, 198, 218, 237,
];

const NLSF_CB1_WGHT_WB_Q9: [i16; 512] = [
    3657, 2925, 2925, 2925, 2925, 2925, 2925, 2925, 2925, 2925, 2925, 2925, 2963, 2963, 2925, 2846,
    3216, 3085, 2972, 3056, 3056, 3010, 3010, 3010, 2963, 2963, 3010, 2972, 2888, 2846, 2846, 2726,
    3920, 4014, 2981, 3207, 3207, 2934, 3056, 2846, 3122, 3244, 2925, 2846, 2620, 2553, 2780, 2925,
    3516, 3197, 3010, 3103, 3019, 2888, 2925, 2925, 2925, 2925, 2888, 2888, 2888, 2888, 2888, 2753,
    5054, 5054, 2934, 3573, 3385, 3056, 3085, 2793, 3160, 3160, 2972, 2846, 2513, 2540, 2753, 2888,
    4428, 4149, 2700, 2753, 2972, 3010, 2925, 2846, 2981, 3019, 2925, 2925, 2925, 2925, 2888, 2726,
    3620, 3019, 2972, 3056, 3056, 2873, 2806, 3056, 3216, 3047, 2981, 3291, 3291, 2981, 3310, 2991,
    5227, 5014, 2540, 3338, 3526, 3385, 3197, 3094, 3376, 2981, 2700, 2647, 2687, 2793, 2846, 2673,
    5081, 5174, 4615, 4428, 2460, 2897, 3047, 3207, 3169, 2687, 2740, 2888, 2846, 2793, 2846, 2700,
    3122, 2888, 2963, 2925, 2925, 2925, 2925, 2963, 2963, 2963, 2963, 2925, 2925, 2963, 2963, 2963,
    4202, 3207, 2981, 3103, 3010, 2888, 2888, 2925, 2972, 2873, 2916, 3019, 2972, 3010, 3197, 2873,
    3760, 3760, 3244, 3103, 2981, 2888, 2925, 2888, 2972, 2934, 2793, 2793, 2846, 2888, 2888, 2660,
    3854, 4014, 3207, 3122, 3244, 2934, 3047, 2963, 2963, 3085, 2846, 2793, 2793, 2793, 2793, 2580,
    3845, 4080, 3357, 3516, 3094, 2740, 3010, 2934, 3122, 3085, 2846, 2846, 2647, 2647, 2846, 2806,
    5147, 4894, 3225, 3845, 3441, 3169, 2897, 3413, 3451, 2700, 2580, 2673, 2740, 2846, 2806, 2753,
    4109, 3789, 3291, 3160, 2925, 2888, 2888, 2925, 2793, 2740, 2793, 2740, 2793, 2846, 2888, 2806,
    5081, 5054, 3047, 3545, 3244, 3056, 3085, 2944, 3103, 2897, 2740, 2740, 2740, 2846, 2793, 2620,
    4309, 4309, 2860, 2527, 3207, 3376, 3376, 3075, 3075, 3376, 3056, 2846, 2647, 2580, 2726, 2753,
    3056, 2916, 2806, 2888, 2740, 2687, 2897, 3103, 3150, 3150, 3216, 3169, 3056, 3010, 2963, 2846,
    4375, 3882, 2925, 2888, 2846, 2888, 2846, 2846, 2888, 2888, 2888, 2846, 2888, 2925, 2888, 2846,
    2981, 2916, 2916, 2981, 2981, 3056, 3122, 3216, 3150, 3056, 3010, 2972, 2972, 2972, 2925, 2740,
    4229, 4149, 3310, 3347, 2925, 2963, 2888, 2981, 2981, 2846, 2793, 2740, 2846, 2846, 2846, 2793,
    4080, 4014, 3103, 3010, 2925, 2925, 2925, 2888, 2925, 2925, 2846, 2846, 2846, 2793, 2888, 2780,
    4615, 4575, 3169, 3441, 3207, 2981, 2897, 3038, 3122, 2740, 2687, 2687, 2687, 2740, 2793, 2700,
    4149, 4269, 3789, 3657, 2726, 2780, 2888, 2888, 3010, 2972, 2925, 2846, 2687, 2687, 2793, 2888,
    4215, 3554, 2753, 2846, 2846, 2888, 2888, 2888, 2925, 2925, 2888, 2925, 2925, 2925, 2963, 2888,
    5174, 4921, 2261, 3432, 3789, 3479, 3347, 2846, 3310, 3479, 3150, 2897, 2460, 2487, 2753, 2925,
    3451, 3685, 3122, 3197, 3357, 3047, 3207, 3207, 2981, 3216, 3085, 2925, 2925, 2687, 2540, 2434,
    2981, 3010, 2793, 2793, 2740, 2793, 2846, 2972, 3056, 3103, 3150, 3150, 3150, 3103, 3010, 3010,
    2944, 2873, 2687, 2726, 2780, 3010, 3432, 3545, 3357, 3244, 3056, 3010, 2963, 2925, 2888, 2846,
    3019, 2944, 2897, 3010, 3010, 2972, 3019, 3103, 3056, 3056, 3010, 2888, 2846, 2925, 2925, 2888,
    3920, 3967, 3010, 3197, 3357, 3216, 3291, 3291, 3479, 3704, 3441, 2726, 2181, 2460, 2580, 2607,
];

const NLSF_PRED_WB_Q8: [u8; 30] = [
    175, 148, 160, 176, 178, 173, 174, 164, 177, 174, 196, 182, 198, 192, 182, 68, 62, 66, 60, 72,
    117, 85, 90, 118, 136, 151, 142, 160, 142, 155,
];

const NLSF_DELTA_MIN_WB_Q15: [i16; 17] =
    [100, 3, 40, 3, 3, 3, 5, 14, 14, 10, 11, 3, 8, 9, 7, 3, 347];

/// Narrowband/mediumband NLSF codebook.
pub(super) const NLSF_CB_NB_MB: NlsfCodebook = NlsfCodebook {
    order: 10,
    quant_step_size_q16: 11_796,
    cb1_nlsf_q8: &NLSF_CB1_NB_MB_Q8,
    cb1_wght_q9: &NLSF_CB1_WGHT_NB_MB_Q9,
    pred_q8: &NLSF_PRED_NB_MB_Q8,
    ec_sel: &super::entropy_tables::NLSF_CB2_SELECT_NB_MB,
    delta_min_q15: &NLSF_DELTA_MIN_NB_MB_Q15,
};

/// Wideband NLSF codebook.
pub(super) const NLSF_CB_WB: NlsfCodebook = NlsfCodebook {
    order: 16,
    quant_step_size_q16: 9_830,
    cb1_nlsf_q8: &NLSF_CB1_WB_Q8,
    cb1_wght_q9: &NLSF_CB1_WGHT_WB_Q9,
    pred_q8: &NLSF_PRED_WB_Q8,
    ec_sel: &super::entropy_tables::NLSF_CB2_SELECT_WB,
    delta_min_q15: &NLSF_DELTA_MIN_WB_Q15,
};

/// Quantization offsets in Q10 indexed by `[signal_type >> 1][quant_offset_type]`.
pub(super) const QUANTIZATION_OFFSETS_Q10: [[i32; 2]; 2] = [
    [OFFSET_UVL_Q10, OFFSET_UVH_Q10],
    [OFFSET_VL_Q10, OFFSET_VH_Q10],
];

/// LTP scaling factors in Q14 indexed by `ltp_scale_index`.
pub(super) const LTP_SCALES_Q14: [i16; 3] = [15_565, 12_288, 8_192];

/// 20 ms pitch contour table for NB stage-2.
pub(super) const CB_LAGS_STAGE2_NB: [[i8; PE_NB_CBKS_STAGE2_EXT]; MAX_NB_SUBFR] = [
    [0, 2, -1, -1, -1, 0, 0, 1, 1, 0, 1],
    [0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0],
    [0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 0],
    [0, -1, 2, 1, 0, 1, 1, 0, 0, -1, -1],
];

/// 20 ms pitch contour table for MB/WB stage-3.
pub(super) const CB_LAGS_STAGE3_WB: [[i8; PE_NB_CBKS_STAGE3_MAX]; MAX_NB_SUBFR] = [
    [
        0, 0, 1, -1, 0, 1, -1, 0, -1, 1, -2, 2, -2, -2, 2, -3, 2, 3, -3, -4, 3, -4, 4, 4, -5, 5,
        -6, -5, 6, -7, 6, 5, 8, -9,
    ],
    [
        0, 0, 1, 0, 0, 0, 0, 0, 0, 0, -1, 1, 0, 0, 1, -1, 0, 1, -1, -1, 1, -1, 2, 1, -1, 2, -2, -2,
        2, -2, 2, 2, 3, -3,
    ],
    [
        0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 1, -1, 1, 0, 0, 2, 1, -1, 2, -1, -1, 2, -1, 2, 2,
        -1, 3, -2, -2, -2, 3,
    ],
    [
        0, 1, 0, 0, 1, 0, 1, -1, 2, -1, 2, -1, 2, 3, -2, 3, -2, -2, 4, 4, -3, 5, -3, -4, 6, -4, 6,
        5, -5, 8, -6, -5, -7, 9,
    ],
];

/// 10 ms pitch contour table for NB stage-2.
pub(super) const CB_LAGS_STAGE2_10MS_NB: [[i8; PE_NB_CBKS_STAGE2_10MS]; 2] = [[0, 1, 0], [0, 0, 1]];

/// 10 ms pitch contour table for MB/WB stage-3.
pub(super) const CB_LAGS_STAGE3_10MS_WB: [[i8; PE_NB_CBKS_STAGE3_10MS]; 2] = [
    [0, 0, 1, -1, 1, -1, 2, -2, 2, -2, 3, -3],
    [0, 1, 0, 1, -1, 2, -1, 2, -2, 3, -2, 3],
];

/// LTP VQ codebook 0 in Q7.
pub(super) const LTP_VQ_0_Q7: [[i8; LTP_ORDER]; 8] = [
    [4, 6, 24, 7, 5],
    [0, 0, 2, 0, 0],
    [12, 28, 41, 13, -4],
    [-9, 15, 42, 25, 14],
    [1, -2, 62, 41, -9],
    [-10, 37, 65, -4, 3],
    [-6, 4, 66, 7, -8],
    [16, 14, 38, -3, 33],
];

/// LTP VQ codebook 1 in Q7.
pub(super) const LTP_VQ_1_Q7: [[i8; LTP_ORDER]; 16] = [
    [13, 22, 39, 23, 12],
    [-1, 36, 64, 27, -6],
    [-7, 10, 55, 43, 17],
    [1, 1, 8, 1, 1],
    [6, -11, 74, 53, -9],
    [-12, 55, 76, -12, 8],
    [-3, 3, 93, 27, -4],
    [26, 39, 59, 3, -8],
    [2, 0, 77, 11, 9],
    [-8, 22, 44, -6, 7],
    [40, 9, 26, 3, 9],
    [-7, 20, 101, -7, 4],
    [3, -8, 42, 26, 0],
    [-15, 33, 68, 2, 23],
    [-2, 55, 46, -2, 15],
    [3, -1, 21, 16, 41],
];

/// LTP VQ codebook 2 in Q7.
pub(super) const LTP_VQ_2_Q7: [[i8; LTP_ORDER]; 32] = [
    [-6, 27, 61, 39, 5],
    [-11, 42, 88, 4, 1],
    [-2, 60, 65, 6, -4],
    [-1, -5, 73, 56, 1],
    [-9, 19, 94, 29, -9],
    [0, 12, 99, 6, 4],
    [8, -19, 102, 46, -13],
    [3, 2, 13, 3, 2],
    [9, -21, 84, 72, -18],
    [-11, 46, 104, -22, 8],
    [18, 38, 48, 23, 0],
    [-16, 70, 83, -21, 11],
    [5, -11, 117, 22, -8],
    [-6, 23, 117, -12, 3],
    [3, -8, 95, 28, 4],
    [-10, 15, 77, 60, -15],
    [-1, 4, 124, 2, -4],
    [3, 38, 84, 24, -25],
    [2, 13, 42, 13, 31],
    [21, -4, 56, 46, -1],
    [-1, 35, 79, -13, 19],
    [-7, 65, 88, -9, -14],
    [20, 4, 81, 49, -29],
    [20, 0, 75, 3, -17],
    [5, -9, 44, 92, -8],
    [1, -3, 22, 69, 31],
    [-6, 95, 41, -12, 5],
    [39, 67, 16, -4, 1],
    [0, -6, 120, 55, -36],
    [-13, 44, 122, 4, -24],
    [81, 5, 11, 3, 7],
    [2, 0, 9, 10, 88],
];

/// Select the NLSF codebook for the current internal SILK rate.
///
/// Params: `fs_khz` is the internal SILK sampling rate in kHz.
/// Returns: NB/MB codebook for 8/12 kHz or WB codebook for 16 kHz.
pub(super) fn nlsf_codebook(fs_khz: u32) -> &'static NlsfCodebook {
    if fs_khz == 16 {
        &NLSF_CB_WB
    } else {
        &NLSF_CB_NB_MB
    }
}