video-parser/src/out.rs

75 lines
2.3 KiB
Rust

use std::io::{stdout, Write};
use ffmpeg::format::Pixel;
#[allow(dead_code)]
pub enum LinesFormat {
/// All lines go to the right.
Right,
/// The first line goes to the right, the next to the left.
RightLeft,
/// The first line goes to the left, the next to the right.
LeftRight,
/// All lines go to the left.
Left,
}
/// Must use square images
pub fn print_square(frame: &ffmpeg::frame::Video, lines_format: LinesFormat, video_index: usize) {
if frame.format() != Pixel::RGB24 { panic!("Must use Pixel::RGB24"); }
if frame.width() != frame.height() { panic!("Must be 1:1 aspect ratio"); }
// This will panic if it's out of bounds.
let z = video_index;
let size = frame.width() as usize;
// How many bytes per pixel RGBA
let linesize = unsafe { std::ptr::addr_of!((*frame.as_ptr()).linesize) };
let step = (unsafe { *linesize })[z] as usize;
let mut stdout = stdout();
let mut lock = stdout.lock();
let buf = frame.data(z);
// (Assuming square) Step thru buffer.
for i in 0..size {
let j = i*step;
// Slices non-inclusively, ie: Even though j(n)+step = j(n+1) the ranges don't overlap. It take from..until
let pre_slice = &buf[j..j+step];
// Only take the size*3 of bytes, ignoring alpha values which are stored after.
// let slice = &pre_slice[0..size*3];
let mut slice = Vec::from(&pre_slice[0..size*3]);
// let lol = &buf[j..j+step][0..size*3];
match lines_format {
LinesFormat::Right => {/* Do nothing */},
LinesFormat::RightLeft => if i & 1 == 1 { reverse(&mut slice) },
LinesFormat::LeftRight => if i & 1 != 1 { reverse(&mut slice) },
LinesFormat::Left => slice.reverse(),
}
// DEBUG
// println!("{:?} || {}-{}", slice, j, j+step);
// NORMAL
lock.write(&slice).unwrap();
}
stdout.flush().unwrap();
}
/// Reverses the order of every grouping of 3 bytes.
fn reverse(raw: & mut [u8]) {
// I would prefer this only went over the elements once,
// not twice.
let x = raw
.iter()
.array_chunks::<3>()
.rev()
.flatten()
.map(|f| *f)
.collect::<Vec<u8>>();
x.iter().enumerate().for_each(|f| raw[f.0] = *f.1);
}