| 1 | //! Output frame reordering. |
| 2 | //! |
| 3 | //! NihAV decoders output frames in the same order as they are put in. |
| 4 | //! In result if you want to have frames in display order you might need some frame reorderer. |
| 5 | //! This module provides such functionality depending on codec type: audio codecs and video codecs without B-frames do not need any reorderer and can use `NoReorderer` if the common interface is required. Codecs with B-frames should use `IPBReorderer`. For codecs with very complex reordering rules like H.264 or H.256 `PictureIDReorderer` will be added eventually. |
| 6 | //! |
| 7 | //! You can find out required reorderer by quering codec properties using `nihav_core::register` module. |
| 8 | use std::mem::swap; |
| 9 | pub use crate::frame::{FrameType, NAFrameRef}; |
| 10 | |
| 11 | /// A trait for frame reorderer. |
| 12 | pub trait FrameReorderer { |
| 13 | /// Stores a newly decoded frame. |
| 14 | fn add_frame(&mut self, fref: NAFrameRef) -> bool; |
| 15 | /// Gets the next frame to be displayed (or `None` if that is not possible). |
| 16 | fn get_frame(&mut self) -> Option<NAFrameRef>; |
| 17 | /// Clears all stored frames. |
| 18 | fn flush(&mut self); |
| 19 | /// Retrieves the last frames stored by the reorderer. |
| 20 | fn get_last_frames(&mut self) -> Option<NAFrameRef>; |
| 21 | } |
| 22 | |
| 23 | /// Zero reorderer. |
| 24 | pub struct NoReorderer { |
| 25 | fref: Option<NAFrameRef>, |
| 26 | } |
| 27 | |
| 28 | impl NoReorderer { |
| 29 | /// Constructs a new instance of `NoReorderer`. |
| 30 | pub fn new() -> Self { |
| 31 | Self { fref: None } |
| 32 | } |
| 33 | } |
| 34 | |
| 35 | impl Default for NoReorderer { |
| 36 | fn default() -> Self { |
| 37 | Self::new() |
| 38 | } |
| 39 | } |
| 40 | |
| 41 | impl FrameReorderer for NoReorderer { |
| 42 | fn add_frame(&mut self, fref: NAFrameRef) -> bool { |
| 43 | if self.fref.is_none() { |
| 44 | self.fref = Some(fref); |
| 45 | true |
| 46 | } else { |
| 47 | false |
| 48 | } |
| 49 | } |
| 50 | fn get_frame(&mut self) -> Option<NAFrameRef> { |
| 51 | let mut ret = None; |
| 52 | swap(&mut ret, &mut self.fref); |
| 53 | ret |
| 54 | } |
| 55 | fn flush(&mut self) { self.fref = None; } |
| 56 | fn get_last_frames(&mut self) -> Option<NAFrameRef> { None } |
| 57 | } |
| 58 | |
| 59 | /// Frame reorderer for codecs with I/P/B frames. |
| 60 | #[derive(Default)] |
| 61 | pub struct IPBReorderer { |
| 62 | rframe: Option<NAFrameRef>, |
| 63 | bframe: Option<NAFrameRef>, |
| 64 | } |
| 65 | |
| 66 | impl IPBReorderer { |
| 67 | /// Constructs a new instance of `IPBReorderer`. |
| 68 | pub fn new() -> Self { Self::default() } |
| 69 | } |
| 70 | |
| 71 | impl FrameReorderer for IPBReorderer { |
| 72 | fn add_frame(&mut self, fref: NAFrameRef) -> bool { |
| 73 | if self.rframe.is_some() && self.bframe.is_some() { return false; } |
| 74 | let is_b = fref.get_frame_type() == FrameType::B; |
| 75 | if is_b && self.bframe.is_some() { return false; } |
| 76 | if is_b { |
| 77 | self.bframe = Some(fref); |
| 78 | } else { |
| 79 | std::mem::swap(&mut self.bframe, &mut self.rframe); |
| 80 | self.rframe = Some(fref); |
| 81 | } |
| 82 | true |
| 83 | } |
| 84 | fn get_frame(&mut self) -> Option<NAFrameRef> { |
| 85 | let mut ret = None; |
| 86 | if self.bframe.is_some() { |
| 87 | std::mem::swap(&mut ret, &mut self.bframe); |
| 88 | } |
| 89 | ret |
| 90 | } |
| 91 | fn flush(&mut self) { |
| 92 | self.rframe = None; |
| 93 | self.bframe = None; |
| 94 | } |
| 95 | fn get_last_frames(&mut self) -> Option<NAFrameRef> { |
| 96 | let mut ret = None; |
| 97 | if self.bframe.is_some() { |
| 98 | std::mem::swap(&mut ret, &mut self.bframe); |
| 99 | } else if self.rframe.is_some() { |
| 100 | std::mem::swap(&mut ret, &mut self.rframe); |
| 101 | } |
| 102 | ret |
| 103 | } |
| 104 | } |
| 105 | |
| 106 | /// Frame reorderer for codecs with complex I/P/B frame structure like ITU H.26x. |
| 107 | #[derive(Default)] |
| 108 | pub struct ComplexReorderer { |
| 109 | last_ref_dts: Option<u64>, |
| 110 | ready_idx: usize, |
| 111 | frames: Vec<NAFrameRef>, |
| 112 | } |
| 113 | |
| 114 | impl ComplexReorderer { |
| 115 | /// Constructs a new instance of `IPBReorderer`. |
| 116 | pub fn new() -> Self { Self::default() } |
| 117 | } |
| 118 | |
| 119 | impl FrameReorderer for ComplexReorderer { |
| 120 | fn add_frame(&mut self, fref: NAFrameRef) -> bool { |
| 121 | if self.frames.len() >= 64 { |
| 122 | return false; |
| 123 | } |
| 124 | let is_ref = fref.frame_type == FrameType::I || fref.frame_type == FrameType::P; |
| 125 | if !is_ref { |
| 126 | if self.frames.is_empty() || fref.get_dts().is_none() { |
| 127 | self.frames.push(fref); |
| 128 | } else if let Some(new_dts) = fref.get_dts() { |
| 129 | let mut idx = 0; |
| 130 | for (i, frm) in self.frames.iter().enumerate() { |
| 131 | idx = i; |
| 132 | if let Some(dts) = frm.get_dts() { |
| 133 | if dts > new_dts { |
| 134 | break; |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | self.frames.insert(idx, fref); |
| 139 | } |
| 140 | } else { |
| 141 | for (i, frm) in self.frames.iter().enumerate() { |
| 142 | if frm.get_dts() == self.last_ref_dts { |
| 143 | self.ready_idx = i + 1; |
| 144 | } |
| 145 | } |
| 146 | self.last_ref_dts = fref.get_dts(); |
| 147 | self.frames.push(fref); |
| 148 | } |
| 149 | true |
| 150 | } |
| 151 | fn get_frame(&mut self) -> Option<NAFrameRef> { |
| 152 | if self.ready_idx > 0 { |
| 153 | self.ready_idx -= 1; |
| 154 | Some(self.frames.remove(0)) |
| 155 | } else { |
| 156 | None |
| 157 | } |
| 158 | } |
| 159 | fn flush(&mut self) { |
| 160 | self.last_ref_dts = None; |
| 161 | self.ready_idx = 0; |
| 162 | self.frames.truncate(0); |
| 163 | } |
| 164 | fn get_last_frames(&mut self) -> Option<NAFrameRef> { |
| 165 | if !self.frames.is_empty() { |
| 166 | Some(self.frames.remove(0)) |
| 167 | } else { |
| 168 | None |
| 169 | } |
| 170 | } |
| 171 | } |
| 172 | |