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use nihav_core::codecs::{DecoderResult, DecoderError};
use nihav_core::io::bitreader::*;
use super::mp2data::*;
#[derive(Default)]
pub struct MP2Data {
pub mpeg1: bool,
pub sf_idx: usize,
pub br_idx: usize,
alloc: [[u8; 32]; 2],
scfsi: [[u8; 32]; 2],
scale: [[[u8; 3]; 32]; 2],
}
fn unquant(val: u8, levels: i16, scale: f32) -> f32 {
(((i16::from(val) << 1) + 1 - levels) as f32) * scale / (levels as f32)
}
fn read3samples(br: &mut BitReader, qbits: i8, scale: f32, band: usize, dst: &mut [[f32; 32]]) -> DecoderResult<()> {
if qbits > 0 {
let bits = qbits as u8;
let maxval = (1 << bits) - 1;
dst[0][band] = unquant(br.read(bits)? as u8, maxval, scale);
dst[1][band] = unquant(br.read(bits)? as u8, maxval, scale);
dst[2][band] = unquant(br.read(bits)? as u8, maxval, scale);
} else {
let samplecode = br.read(-qbits as u8)? as usize;
match qbits {
-5 => {
for i in 0..3 {
dst[i][band] = unquant(GROUP3[samplecode][i], 3, scale);
}
},
-7 => {
for i in 0..3 {
dst[i][band] = unquant(GROUP5[samplecode][i], 5, scale);
}
},
-10 => {
for i in 0..3 {
dst[i][band] = unquant(GROUP9[samplecode][i], 9, scale);
}
},
_ => unreachable!(),
};
}
Ok(())
}
fn read3samples_joint(br: &mut BitReader, qbits: i8, scale0: f32, scale1: f32, band: usize, gr: usize, dst: &mut [[[f32; 32]; 36]; 2]) -> DecoderResult<()> {
if qbits > 0 {
let bits = qbits as u8;
let maxval = (1 << bits) - 1;
for i in 0..3 {
let val = br.read(bits)? as u8;
dst[0][gr * 3 + i][band] = unquant(val, maxval, scale0);
dst[1][gr * 3 + i][band] = unquant(val, maxval, scale1);
}
} else {
let samplecode = br.read(-qbits as u8)? as usize;
match qbits {
-5 => {
for i in 0..3 {
dst[0][gr * 3 + i][band] = unquant(GROUP3[samplecode][i], 3, scale0);
dst[1][gr * 3 + i][band] = unquant(GROUP3[samplecode][i], 3, scale1);
}
},
-7 => {
for i in 0..3 {
dst[0][gr * 3 + i][band] = unquant(GROUP5[samplecode][i], 5, scale0);
dst[1][gr * 3 + i][band] = unquant(GROUP5[samplecode][i], 5, scale1);
}
},
-10 => {
for i in 0..3 {
dst[0][gr * 3 + i][band] = unquant(GROUP9[samplecode][i], 9, scale0);
dst[1][gr * 3 + i][band] = unquant(GROUP9[samplecode][i], 9, scale1);
}
},
_ => unreachable!(),
};
}
Ok(())
}
impl MP2Data {
pub fn new() -> Self { Self::default() }
pub fn read_layer2(&mut self, br: &mut BitReader, channels: usize, out: &mut [[[f32; 32]; 36]; 2], mode: u8, mode_extension: u8) -> DecoderResult<()> {
let (ba_bits, ba_quants) = if self.mpeg1 {
if channels == 1 {
(LAYER2_BITS[self.sf_idx][self.br_idx], LAYER2_ALLOC[self.br_idx])
} else {
let br_idx = HALF_BITRATE_IDX[self.br_idx] as usize;
(LAYER2_BITS[self.sf_idx][br_idx], LAYER2_ALLOC[br_idx])
}
} else {
(BITS_B2LFE, ALLOC_B2LFE)
};
let mut sblimit = ba_bits.len() - 1;
while sblimit > 0 && ba_bits[sblimit - 1] == 0 {
sblimit -= 1;
}
if sblimit == 0 {
return Err(DecoderError::Bug);
}
*out = [[[0.0; 32]; 36]; 2];
if channels == 1 {
for (bits, &b) in self.alloc[0][..sblimit].iter_mut().zip(ba_bits.iter()) {
*bits = br.read(b)? as u8;
}
for (scf, &alloc) in self.scfsi[0][..sblimit].iter_mut().zip(self.alloc[0].iter()) {
if alloc != 0 {
*scf = br.read(2)? as u8;
}
}
for (band, scales) in self.scale[0].iter_mut().take(sblimit).enumerate() {
if self.alloc[0][band] == 0 {
continue;
}
scales[0] = br.read(6)? as u8;
match self.scfsi[0][band] {
0 => {
scales[1] = br.read(6)? as u8;
scales[2] = br.read(6)? as u8;
},
1 => {
scales[1] = scales[0];
scales[2] = br.read(6)? as u8;
},
2 => {
scales[1] = scales[0];
scales[2] = scales[0];
},
_ => {
scales[1] = br.read(6)? as u8;
scales[2] = scales[1];
},
};
}
for gr in 0..12 {
for band in 0..sblimit {
if self.alloc[0][band] == 0 {
continue;
}
let scale = QUANTS[self.scale[0][band][gr / 4] as usize];
let qbits = ba_quants[band][self.alloc[0][band] as usize];
read3samples(br, qbits, scale, band, &mut out[0][gr * 3..])?;
}
}
} else {
let mut bound = if mode == 1 {
(mode_extension as usize + 1) * 4
} else {
sblimit
};
while bound > 0 && ba_bits[bound - 1] == 0 {
bound -= 1;
}
for band in 0..sblimit {
self.alloc[0][band] = br.read(ba_bits[band])? as u8;
if band < bound {
self.alloc[1][band] = br.read(ba_bits[band])? as u8;
} else {
self.alloc[1][band] = self.alloc[0][band];
}
}
for band in 0..sblimit {
for ch in 0..2 {
if self.alloc[ch][band] != 0 {
self.scfsi[ch][band] = br.read(2)? as u8;
}
}
}
for band in 0..sblimit {
for ch in 0..2 {
if self.alloc[ch][band] == 0 {
continue;
}
let scales = &mut self.scale[ch][band];
scales[0] = br.read(6)? as u8;
match self.scfsi[ch][band] {
0 => {
scales[1] = br.read(6)? as u8;
scales[2] = br.read(6)? as u8;
},
1 => {
scales[1] = scales[0];
scales[2] = br.read(6)? as u8;
},
2 => {
scales[1] = scales[0];
scales[2] = scales[0];
},
_ => {
scales[1] = br.read(6)? as u8;
scales[2] = scales[1];
},
};
}
}
for gr in 0..12 {
for band in 0..bound {
for ch in 0..2 {
if self.alloc[ch][band] == 0 {
continue;
}
let scale = QUANTS[self.scale[ch][band][gr / 4] as usize];
let qbits = ba_quants[band][self.alloc[ch][band] as usize];
read3samples(br, qbits, scale, band, &mut out[ch][gr * 3..])?;
}
}
for band in bound..sblimit {
if self.alloc[0][band] == 0 {
continue;
}
let scale0 = QUANTS[self.scale[0][band][gr / 4] as usize];
let scale1 = QUANTS[self.scale[1][band][gr / 4] as usize];
let qbits = ba_quants[band][self.alloc[0][band] as usize];
read3samples_joint(br, qbits, scale0, scale1, band, gr, out)?;
}
}
}
Ok(())
}
pub fn reset(&mut self) {
}
}
|
