av_scenechange/
y4m.rs

1use std::io::Read;
2
3use num_rational::Rational32;
4use v_frame::{
5    frame::Frame,
6    pixel::{ChromaSampling, Pixel},
7};
8
9use crate::decoder::VideoDetails;
10
11pub fn get_video_details<R: Read>(dec: &y4m::Decoder<R>) -> VideoDetails {
12    let width = dec.get_width();
13    let height = dec.get_height();
14    let color_space = dec.get_colorspace();
15    let bit_depth = color_space.get_bit_depth();
16    let chroma_sampling = map_y4m_color_space(color_space);
17    let framerate = dec.get_framerate();
18    let time_base = Rational32::new(framerate.den as i32, framerate.num as i32);
19
20    VideoDetails {
21        width,
22        height,
23        bit_depth,
24        chroma_sampling,
25        time_base,
26    }
27}
28
29const fn map_y4m_color_space(color_space: y4m::Colorspace) -> ChromaSampling {
30    use y4m::Colorspace::{
31        C420jpeg,
32        C420mpeg2,
33        C420p10,
34        C420p12,
35        C420paldv,
36        C422p10,
37        C422p12,
38        C444p10,
39        C444p12,
40        Cmono,
41        Cmono12,
42        C420,
43        C422,
44        C444,
45    };
46    use ChromaSampling::{Cs400, Cs420, Cs422, Cs444};
47    match color_space {
48        Cmono | Cmono12 => Cs400,
49        C420jpeg | C420paldv => Cs420,
50        C420mpeg2 => Cs420,
51        C420 | C420p10 | C420p12 => Cs420,
52        C422 | C422p10 | C422p12 => Cs422,
53        C444 | C444p10 | C444p12 => Cs444,
54        _ => unimplemented!(),
55    }
56}
57
58pub fn read_video_frame<R: Read, T: Pixel>(
59    dec: &mut y4m::Decoder<R>,
60    cfg: &VideoDetails,
61) -> anyhow::Result<Frame<T>> {
62    const SB_SIZE_LOG2: usize = 6;
63    const SB_SIZE: usize = 1 << SB_SIZE_LOG2;
64    const SUBPEL_FILTER_SIZE: usize = 8;
65    const FRAME_MARGIN: usize = 16 + SUBPEL_FILTER_SIZE;
66    const LUMA_PADDING: usize = SB_SIZE + FRAME_MARGIN;
67
68    let bytes = dec.get_bytes_per_sample();
69    dec.read_frame()
70        .map(|frame| {
71            let mut f: Frame<T> =
72                Frame::new_with_padding(cfg.width, cfg.height, cfg.chroma_sampling, LUMA_PADDING);
73
74            let (chroma_width, _) = cfg
75                .chroma_sampling
76                .get_chroma_dimensions(cfg.width, cfg.height);
77
78            f.planes[0].copy_from_raw_u8(frame.get_y_plane(), cfg.width * bytes, bytes);
79            f.planes[1].copy_from_raw_u8(frame.get_u_plane(), chroma_width * bytes, bytes);
80            f.planes[2].copy_from_raw_u8(frame.get_v_plane(), chroma_width * bytes, bytes);
81            f
82        })
83        .map_err(|e| e.into())
84}
av_scenechange/y4m.rs

av_scenechange/
y4m.rs
