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// Copyright (c) 2018, The rav1e contributors. All rights reserved
//
// This source code is subject to the terms of the BSD 2 Clause License and
// the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
// was not distributed with this source code in the LICENSE file, you can
// obtain it at www.aomedia.org/license/software. If the Alliance for Open
// Media Patent License 1.0 was not distributed with this source code in the
// PATENTS file, you can obtain it at www.aomedia.org/license/patent.

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use bitstream_io::*;
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use encoder::*;
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use metrics::calculate_frame_psnr;
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use partition::*;
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use scenechange::SceneChangeDetector;
use self::EncoderStatus::*;
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use std::{cmp, fmt, io};
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use std::collections::BTreeMap;
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use std::sync::Arc;

// TODO: use the num crate?
#[derive(Clone, Copy, Debug)]
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#[repr(C)]
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pub struct Rational {
  pub num: u64,
  pub den: u64
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}

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impl Rational {
  pub fn new(num: u64, den: u64) -> Self {
    Rational { num, den }
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  }
}

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#[derive(Copy, Clone, Debug)]
pub struct EncoderConfig {
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  /// The *minimum* interval between two keyframes
  pub min_key_frame_interval: u64,
  /// The *maximum* interval between two keyframes
  pub max_key_frame_interval: u64,
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  pub low_latency: bool,
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  pub quantizer: usize,
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  pub tune: Tune,
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  pub color_description: Option<ColorDescription>,
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  pub speed_settings: SpeedSettings,
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  pub show_psnr: bool,
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}

impl Default for EncoderConfig {
  fn default() -> Self {
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    const DEFAULT_SPEED: usize = 3;
    Self::with_speed_preset(DEFAULT_SPEED)
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  }
}

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impl EncoderConfig {
  pub fn with_speed_preset(speed: usize) -> Self {
    EncoderConfig {
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      min_key_frame_interval: 12,
      max_key_frame_interval: 240,
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      low_latency: true,
      quantizer: 100,
      tune: Tune::Psnr,
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      color_description: None,
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      speed_settings: SpeedSettings::from_preset(speed),
      show_psnr: false,
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    }
  }
}

#[derive(Clone, Copy, Debug)]
pub struct SpeedSettings {
  pub min_block_size: BlockSize,
  pub multiref: bool,
  pub fast_deblock: bool,
  pub reduced_tx_set: bool,
  pub tx_domain_distortion: bool,
  pub encode_bottomup: bool,
  pub rdo_tx_decision: bool,
  pub prediction_modes: PredictionModesSetting,
  pub include_near_mvs: bool,
}

impl SpeedSettings {
  pub fn from_preset(speed: usize) -> Self {
    SpeedSettings {
      min_block_size: Self::min_block_size_preset(speed),
      multiref: Self::multiref_preset(speed),
      fast_deblock: Self::fast_deblock_preset(speed),
      reduced_tx_set: Self::reduced_tx_set_preset(speed),
      tx_domain_distortion: Self::tx_domain_distortion_preset(speed),
      encode_bottomup: Self::encode_bottomup_preset(speed),
      rdo_tx_decision: Self::rdo_tx_decision_preset(speed),
      prediction_modes: Self::prediction_modes_preset(speed),
      include_near_mvs: Self::include_near_mvs_preset(speed),
    }
  }

  fn min_block_size_preset(speed: usize) -> BlockSize {
    if speed <= 1 {
      BlockSize::BLOCK_4X4
    } else if speed <= 2 {
      BlockSize::BLOCK_8X8
    } else if speed <= 3 {
      BlockSize::BLOCK_16X16
    } else if speed <= 4 {
      BlockSize::BLOCK_32X32
    } else {
      BlockSize::BLOCK_64X64
    }
  }

  fn multiref_preset(speed: usize) -> bool {
    speed <= 2
  }

  fn fast_deblock_preset(speed: usize) -> bool {
    speed >= 4
  }

  fn reduced_tx_set_preset(speed: usize) -> bool {
    speed >= 2
  }

  fn tx_domain_distortion_preset(speed: usize) -> bool {
    speed >= 1
  }

  fn encode_bottomup_preset(speed: usize) -> bool {
    speed == 0
  }

  fn rdo_tx_decision_preset(speed: usize) -> bool {
    speed <= 3
  }

  fn prediction_modes_preset(speed: usize) -> PredictionModesSetting {
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    if speed <= 3 {
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      PredictionModesSetting::ComplexAll
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    } else if speed <= 4 {
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      PredictionModesSetting::ComplexKeyframes
    } else {
      PredictionModesSetting::Simple
    }
  }

  fn include_near_mvs_preset(speed: usize) -> bool {
    speed <= 2
  }
}

#[derive(Clone, Copy, Debug, PartialOrd, PartialEq)]
pub enum PredictionModesSetting {
  Simple,
  ComplexKeyframes,
  ComplexAll,
}

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arg_enum!{
  #[derive(Debug, Clone, Copy, PartialEq)]
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  #[repr(C)]
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  pub enum MatrixCoefficients {
      Identity = 0,
      BT709,
      Unspecified,
      BT470M = 4,
      BT470BG,
      ST170M,
      ST240M,
      YCgCo,
      BT2020NonConstantLuminance,
      BT2020ConstantLuminance,
      ST2085,
      ChromaticityDerivedNonConstantLuminance,
      ChromaticityDerivedConstantLuminance,
      ICtCp,
  }
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}

impl Default for MatrixCoefficients {
    fn default() -> Self {
        MatrixCoefficients::Unspecified
    }
}

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arg_enum!{
  #[derive(Debug,Clone,Copy,PartialEq)]
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  #[repr(C)]
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  pub enum ColorPrimaries {
      BT709 = 1,
      Unspecified,
      BT470M = 4,
      BT470BG,
      ST170M,
      ST240M,
      Film,
      BT2020,
      ST428,
      P3DCI,
      P3Display,
      Tech3213 = 22,
  }
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}

impl Default for ColorPrimaries {
    fn default() -> Self {
        ColorPrimaries::Unspecified
    }
}

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arg_enum!{
  #[derive(Debug,Clone,Copy,PartialEq)]
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  #[repr(C)]
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  pub enum TransferCharacteristics {
      BT1886 = 1,
      Unspecified,
      BT470M = 4,
      BT470BG,
      ST170M,
      ST240M,
      Linear,
      Logarithmic100,
      Logarithmic316,
      XVYCC,
      BT1361E,
      SRGB,
      BT2020Ten,
      BT2020Twelve,
      PerceptualQuantizer,
      ST428,
      HybridLogGamma,
  }
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}

impl Default for TransferCharacteristics {
    fn default() -> Self {
        TransferCharacteristics::Unspecified
    }
}

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#[derive(Copy, Clone, Debug)]
pub struct ColorDescription {
    pub color_primaries: ColorPrimaries,
    pub transfer_characteristics: TransferCharacteristics,
    pub matrix_coefficients: MatrixCoefficients
}

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/// Frame-specific information
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#[derive(Clone, Copy, Debug, Default)]
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pub struct FrameInfo {
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  pub width: usize,
  pub height: usize,
  pub bit_depth: usize,
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  pub chroma_sampling: ChromaSampling,
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  pub chroma_sample_position: ChromaSamplePosition
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}

/// Contain all the encoder configuration
#[derive(Clone, Copy, Debug)]
pub struct Config {
  pub frame_info: FrameInfo,
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  pub timebase: Rational,
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  pub enc: EncoderConfig
}

impl Config {
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  pub fn parse(&mut self, key: &str, value: &str) -> Result<(), EncoderStatus> {
    match key {
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      "low_latency" => self.enc.low_latency = value.parse().map_err(|_e| ParseError)?,
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      "min_key_frame_interval" => self.enc.min_key_frame_interval = value.parse().map_err(|_e| ParseError)?,
      "key_frame_interval" => self.enc.max_key_frame_interval = value.parse().map_err(|_e| ParseError)?,
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      "quantizer" => self.enc.quantizer = value.parse().map_err(|_e| ParseError)?,
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      "speed" => self.enc.speed_settings = SpeedSettings::from_preset(value.parse().map_err(|_e| ParseError)?),
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      "tune" => self.enc.tune = value.parse().map_err(|_e| ParseError)?,
      _ => return Err(InvalidKey)
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    }

    Ok(())
  }

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  pub fn new_context(&self) -> Context {
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    let fi = FrameInvariants::new(
      self.frame_info.width,
      self.frame_info.height,
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      self.enc
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    );
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    let seq = Sequence::new(&self.frame_info);
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    #[cfg(feature = "aom")]
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    unsafe {
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      av1_rtcd();
      aom_dsp_rtcd();
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    }

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    Context {
      fi,
      seq,
      frame_count: 0,
      frames_to_be_coded: 0,
      idx: 0,
      frame_q: BTreeMap::new(),
      packet_data: Vec::new(),
      segment_start_idx: 0,
      segment_start_frame: 0,
      frame_types: BTreeMap::new(),
      keyframe_detector: SceneChangeDetector::new(&self.frame_info),
    }
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  }
}

pub struct Context {
  fi: FrameInvariants,
  seq: Sequence,
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  //    timebase: Rational,
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  frame_count: u64,
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  frames_to_be_coded: u64,
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  idx: u64,
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  frame_q: BTreeMap<u64, Option<Arc<Frame>>>, //    packet_q: VecDeque<Packet>
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  packet_data: Vec<u8>,
  segment_start_idx: u64,
  segment_start_frame: u64,
  frame_types: BTreeMap<u64, FrameType>,
  keyframe_detector: SceneChangeDetector,
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}

#[derive(Clone, Copy, Debug)]
pub enum EncoderStatus {
  /// The encoder needs more Frames to produce an output Packet
  NeedMoreData,
  /// There are enough Frames queue
  EnoughData,
  ///
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  Failure,
  InvalidKey,
  ParseError
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}

pub struct Packet {
  pub data: Vec<u8>,
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  pub rec: Option<Frame>,
  pub number: u64,
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  pub frame_type: FrameType,
  /// PSNR for Y, U, and V planes
  pub psnr: Option<(f64, f64, f64)>,
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}

impl fmt::Display for Packet {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
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    write!(
      f,
      "Frame {} - {} - {} bytes",
      self.number,
      self.frame_type,
      self.data.len()
    )
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  }
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}

impl Context {
  pub fn new_frame(&self) -> Arc<Frame> {
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    Arc::new(Frame::new(self.fi.padded_w, self.fi.padded_h, self.seq.chroma_sampling))
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  }

  pub fn send_frame<F>(&mut self, frame: F) -> Result<(), EncoderStatus>
  where
    F: Into<Option<Arc<Frame>>>
  {
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    let idx = self.frame_count;
    self.frame_q.insert(idx, frame.into());
    self.save_frame_type(idx);
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    self.frame_count = self.frame_count + 1;
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    Ok(())
  }

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  pub fn get_frame_count(&self) -> u64 {
    self.frame_count
  }

  pub fn set_frames_to_be_coded(&mut self, frames_to_be_coded: u64) {
    self.frames_to_be_coded = frames_to_be_coded;
  }

  pub fn needs_more_frames(&self, frame_count: u64) -> bool {
    self.frames_to_be_coded == 0 || frame_count < self.frames_to_be_coded
  }

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  pub fn container_sequence_header(&mut self) -> Vec<u8> {
    fn sequence_header_inner(seq: &Sequence) -> io::Result<Vec<u8>> {
      let mut buf = Vec::new();
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      {
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        let mut bw = BitWriter::endian(&mut buf, BigEndian);
        bw.write_bit(true)?; // marker
        bw.write(7, 1)?; // version
        bw.write(3, seq.profile)?;
        bw.write(5, 32)?; // level
        bw.write_bit(false)?; // tier
        bw.write_bit(seq.bit_depth > 8)?; // high_bitdepth
        bw.write_bit(seq.bit_depth == 12)?; // twelve_bit
        bw.write_bit(seq.bit_depth == 1)?; // monochrome
        bw.write_bit(seq.bit_depth == 12)?; // twelve_bit
        bw.write_bit(seq.chroma_sampling != ChromaSampling::Cs444)?; // chroma_subsampling_x
        bw.write_bit(seq.chroma_sampling == ChromaSampling::Cs420)?; // chroma_subsampling_y
        bw.write(2, 0)?; // sample_position
        bw.write(3, 0)?; // reserved
        bw.write_bit(false)?; // initial_presentation_delay_present

        bw.write(4, 0)?; // reserved
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      }
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      Ok(buf)
    }

    sequence_header_inner(&self.seq).unwrap()
  }

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  fn next_keyframe(&self) -> u64 {
    let next_detected = self.frame_types.iter()
      .find(|(&i, &ty)| ty == FrameType::KEY && i > self.segment_start_frame)
      .map(|(&i, _)| i);
    let next_limit = self.segment_start_frame + self.fi.config.max_key_frame_interval;
    if next_detected.is_none() {
      return next_limit;
    }
    cmp::min(next_detected.unwrap(), next_limit)
  }
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  fn set_frame_properties(&mut self, idx: u64) -> Result<(), ()> {
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    if idx == 0 {
      // The first frame will always be a key frame
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      self.fi = FrameInvariants::new_key_frame(&self.fi,0);
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      return Ok(());
    }

    // Initially set up the frame as an inter frame.
    // We need to determine what the frame number is before we can
    // look up the frame type. If reordering is enabled, the idx
    // may not match the frame number.
    let idx_in_segment = idx - self.segment_start_idx;
    if idx_in_segment > 0 {
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      let next_keyframe = self.next_keyframe();
      let (fi, success) = FrameInvariants::new_inter_frame(&self.fi, self.segment_start_frame, idx_in_segment, next_keyframe);
      self.fi = fi;
      if !success {
        if !self.fi.inter_cfg.unwrap().reorder || ((idx_in_segment - 1) % self.fi.inter_cfg.unwrap().group_len == 0 && self.fi.number == (next_keyframe - 1)) {
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          self.segment_start_idx = idx;
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          self.segment_start_frame = next_keyframe;
          self.fi.number = next_keyframe;
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        } else {
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          return Err(());
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        }
      }
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    }
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    // Now that we know the frame number, look up the correct frame type
    let frame_type = self.frame_types.get(&self.fi.number).cloned();
    if let Some(frame_type) = frame_type {
      if frame_type == FrameType::KEY {
        self.segment_start_idx = idx;
        self.segment_start_frame = self.fi.number;
      }
      self.fi.frame_type = frame_type;

      let idx_in_segment = idx - self.segment_start_idx;
      if idx_in_segment == 0 {
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        self.fi = FrameInvariants::new_key_frame(&self.fi, self.segment_start_frame);
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      } else {
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        let next_keyframe = self.next_keyframe();
        let (fi, success) = FrameInvariants::new_inter_frame(&self.fi, self.segment_start_frame, idx_in_segment, next_keyframe);
        self.fi = fi;
        if !success {
          return Err(());
        }
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      }
    }
    Ok(())
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  }
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  pub fn receive_packet(&mut self) -> Result<Packet, EncoderStatus> {
    let mut idx = self.idx;
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    while self.set_frame_properties(idx).is_err() {
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      self.idx += 1;
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      idx = self.idx;
    }
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    if !self.needs_more_frames(self.fi.number) {
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      self.idx += 1;
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      return Err(EncoderStatus::EnoughData)
    }

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    if self.fi.show_existing_frame {
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      self.idx += 1;
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      let mut fs = FrameState::new(&self.fi, self.seq.chroma_sampling);
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      let data = encode_frame(&mut self.seq, &mut self.fi, &mut fs);
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      let rec = if self.fi.show_frame { Some(fs.rec) } else { None };
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      let mut psnr = None;
      if self.fi.config.show_psnr {
        if let Some(ref rec) = rec {
          psnr = Some(calculate_frame_psnr(&*fs.input, rec, self.seq.bit_depth));
        }
      }
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      Ok(Packet { data, rec, number: self.fi.number, frame_type: self.fi.frame_type, psnr })
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    } else {
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      if let Some(f) = self.frame_q.remove(&self.fi.number) {
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        self.idx += 1;
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        if let Some(frame) = f {
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          let mut fs = FrameState::new_with_frame(&self.fi, frame.clone(),
            self.seq.chroma_sampling);
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          let data = encode_frame(&mut self.seq, &mut self.fi, &mut fs);
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          self.packet_data.extend(data);
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          fs.rec.pad(self.fi.width, self.fi.height);
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          // TODO avoid the clone by having rec Arc.
          let rec = if self.fi.show_frame { Some(fs.rec.clone()) } else { None };

          update_rec_buffer(&mut self.fi, fs);

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          if self.fi.show_frame {
            let data = self.packet_data.clone();
            self.packet_data = Vec::new();
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            let mut psnr = None;
            if self.fi.config.show_psnr {
              if let Some(ref rec) = rec {
                psnr = Some(calculate_frame_psnr(&*frame, rec, self.seq.bit_depth));
              }
            }

            Ok(Packet { data, rec, number: self.fi.number, frame_type: self.fi.frame_type, psnr })
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          } else {
            Err(EncoderStatus::NeedMoreData)
          }
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        } else {
          Err(EncoderStatus::NeedMoreData)
        }
      } else {
        Err(EncoderStatus::NeedMoreData)
      }
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    }
  }

  pub fn flush(&mut self) {
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    self.frame_q.insert(self.frame_count, None);
    self.frame_count = self.frame_count + 1;
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  }
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  fn save_frame_type(&mut self, idx: u64) {
    let frame_type = self.determine_frame_type(idx);
    self.frame_types.insert(idx, frame_type);
  }

  fn determine_frame_type(&mut self, idx: u64) -> FrameType {
    if idx == 0 {
      return FrameType::KEY;
    }

    let prev_keyframe = *self.frame_types.iter().rfind(|(_, &ty)| ty == FrameType::KEY).unwrap().0;
    let frame = self.frame_q.get(&idx).cloned().unwrap();
    if let Some(frame) = frame {
      let distance = idx - prev_keyframe;
      if distance < self.fi.config.min_key_frame_interval {
        if distance + 1 == self.fi.config.min_key_frame_interval {
          // Run the detector for the current frame, so that it will contain this frame's information
          // to compare against the next frame. We can ignore the results for this frame.
          self.keyframe_detector.detect_scene_change(frame, idx as usize);
        }
        return FrameType::INTER;
      }
      if distance >= self.fi.config.max_key_frame_interval {
        return FrameType::KEY;
      }
      if self.keyframe_detector.detect_scene_change(frame, idx as usize) {
        return FrameType::KEY;
      }
    }
    FrameType::INTER
  }
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impl fmt::Display for Context {
  fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
    write!(f, "Frame {} - {}", self.fi.number, self.fi.frame_type)
  }
}