syom 0.6.0

just aac. Pure-Rust AAC-LC / HE-AAC codec: decode (ADTS, M4A, LATM) and LC encode.
Documentation 
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//! `individual_channel_stream()` — ISO/IEC 14496-3 Table 4.44 (LC, no gain control).

use super::bits::BitReader;
use super::error::{Error, Result};
use super::ics::IcsInfo;
use super::section::SectionData;
use super::sf::{self, ScaleFactors};
use super::spectrum::{self, PulseData};

/// One channel's decoded spectrum (window-major) plus the tools it needs.
#[allow(dead_code)]
#[derive(Debug, Clone)]
pub struct ChannelBody {
    /// ICS of this channel (shared with the pair when `common_window`).
    pub ics: IcsInfo,
    /// Section codebooks.
    pub sections: SectionData,
    /// Absolute scalefactors / IS / PNS energies.
    pub sf: ScaleFactors,
    /// Inverse-quantised, scalefactor-applied spectrum (PNS bands still 0).
    pub spec: Vec<f32>,
    /// Optional TNS payload.
    pub tns: Option<super::tns::TnsData>,
}

/// Parse one `individual_channel_stream(common_window, scale_flag=0)`.
pub fn parse_ics(
    br: &mut BitReader<'_>,
    fs_index: u8,
    aot: u8,
    common: Option<&IcsInfo>,
) -> Result<ChannelBody> {
    let mut quant = Vec::new();
    let mut spec = Vec::new();
    let mut sections = SectionData::default();
    let mut sf = ScaleFactors::default();
    let (ics, tns) = parse_ics_into(
        br,
        fs_index,
        aot,
        common,
        &mut quant,
        &mut spec,
        &mut sections,
        &mut sf,
    )?;
    Ok(ChannelBody {
        ics,
        sections,
        sf,
        spec,
        tns,
    })
}

/// Parse into caller-owned buffers (capacity reused across frames).
#[allow(clippy::too_many_arguments)]
pub fn parse_ics_into(
    br: &mut BitReader<'_>,
    fs_index: u8,
    _aot: u8,
    common: Option<&IcsInfo>,
    quant: &mut Vec<i32>,
    spec: &mut Vec<f32>,
    sections: &mut SectionData,
    sf: &mut ScaleFactors,
) -> Result<(IcsInfo, Option<super::tns::TnsData>)> {
    let global_gain = br.read(8)? as u8;
    let ics = if let Some(shared) = common {
        *shared
    } else {
        IcsInfo::parse(br, fs_index, false)?
    };
    sections.parse_into(br, &ics)?;
    sf::parse_into(br, &ics, &sections.sfb_cb, global_gain, sf)?;
    let pulse_present = br.read_bit()?;
    let pulse = if pulse_present {
        if ics.window_sequence.is_eight_short() {
            return Err(Error::Format("pulse_data on eight_short"));
        }
        Some(PulseData::parse(br)?)
    } else {
        None
    };
    let tns_present = br.read_bit()?;
    let tns = if tns_present {
        Some(super::tns::TnsData::parse(br, &ics)?)
    } else {
        None
    };
    let gain_present = br.read_bit()?;
    if gain_present {
        return Err(Error::Format("gain_control_data is SSR, not LC"));
    }
    spectrum::parse_quant_into(br, &ics, sections, fs_index, quant)?;
    if let Some(p) = pulse.as_ref() {
        spectrum::apply_pulse(quant, fs_index, p)?;
    }
    spectrum::rescale_into(quant, &ics, sections, sf, fs_index, spec)?;
    Ok((ics, tns))
}