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M10.4: parallel baseline JPEG encoder (restart-interval bands, AAN DCT)
Own T.81 encoder: Annex K tables, JFIF YCbCr 4:4:4/4:2:0 + gray, EXIF/XMP/ICC segments, bands of MCU rows separated by RSTn so entropy coding runs on all cores. Per-core speed matches jpeg-encoder at 4:4:4 (225 vs 237 ms on 24 MP, single thread); with all cores 24 MP encodes in ~130 ms vs ~500–800 ms (loaded machine). Output decodes with jpeg-decoder and zune-jpeg (odd sizes tested); same-or-smaller files at equal/higher PSNR. 4:2:2 keeps jpeg-encoder. Bench: crates/codecs/examples/jpeg_bench.rs. Co-Authored-By: Claude Opus 5.5 <[email protected]>
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Brandon ThomasandClaude Opus 5.5 committed
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@@ -0,0 +1,61 @@
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//! Compare the parallel JPEG encoder with `jpeg-encoder` (size, time, PSNR):
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//! `cargo run --release -p lightcraft-codecs --example jpeg_bench [image]` (default: 6000×4000 synthetic).
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use lightcraft_codecs::ChromaSubsampling;
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use std::time::Instant;
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fn psnr(a: &[u8], b: &[u8]) -> f64 {
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let mse = a.iter().zip(b).map(|(x, y)| (*x as f64 - *y as f64).powi(2)).sum::<f64>() / a.len() as f64;
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10.0 * (255.0f64.powi(2) / mse.max(1e-9)).log10()
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}
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fn best<T>(n: usize, mut f: impl FnMut() -> T) -> (T, f64) {
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let mut out = None;
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let mut t = f64::MAX;
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for _ in 0..n {
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let s = Instant::now();
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let r = f();
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t = t.min(s.elapsed().as_secs_f64() * 1e3);
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out = Some(r);
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}
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(out.unwrap(), t)
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}
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fn main() {
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let (w, h, rgb) = match std::env::args().nth(1) {
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Some(p) => {
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let img = image::open(p).expect("open").to_rgb8();
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(img.width() as usize, img.height() as usize, img.into_raw())
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}
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None => {
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let (w, h) = (6000, 4000);
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let mut v = Vec::with_capacity(w * h * 3);
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for y in 0..h {
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for x in 0..w {
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let t = (((x as f32 / 37.0).sin() * (y as f32 / 23.0).cos()) * 0.5 + 0.5) * 255.0;
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v.extend_from_slice(&[(x * 255 / w) as u8, t as u8, ((x ^ y) & 0xff) as u8]);
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}
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}
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(w, h, v)
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}
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};
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for (sub, js) in
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[(ChromaSubsampling::S444, jpeg_encoder::SamplingFactor::R_4_4_4), (ChromaSubsampling::S420, jpeg_encoder::SamplingFactor::R_4_2_0)]
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{
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let (ours, t_ours) = best(5, || lightcraft_codecs::jpeg_par::encode(&rgb, w, h, 3, 90, sub, &[]));
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let (theirs, t_theirs) = best(3, || {
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let mut out = Vec::new();
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let mut e = jpeg_encoder::Encoder::new(&mut out, 90);
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e.set_sampling_factor(js);
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e.encode(&rgb, w as u16, h as u16, jpeg_encoder::ColorType::Rgb).unwrap();
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out
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});
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let dec = |b: &[u8]| jpeg_decoder::Decoder::new(b).decode().unwrap();
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println!(
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"{w}x{h} {sub:?} q90: parallel {t_ours:.0} ms, {} KB, PSNR {:.2} dB | jpeg-encoder {t_theirs:.0} ms, {} KB, PSNR {:.2} dB",
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ours.len() / 1024,
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psnr(&rgb, &dec(&ours)),
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theirs.len() / 1024,
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psnr(&rgb, &dec(&theirs))
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);
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}
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}
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@@ -93,6 +93,36 @@ pub fn encode_jpeg(img: &EncodeImage, quality: u8, subsampling: ChromaSubsamplin
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3 => (data[..n * 3].into(), jpeg_encoder::ColorType::Rgb),
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_ => (data[..n * 4].into(), jpeg_encoder::ColorType::Rgba),
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};
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if subsampling != ChromaSubsampling::S422 {
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// Parallel encoder (restart-interval bands on all cores).
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let mut segs: Vec<(u8, Vec<u8>)> = Vec::new();
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if let Some(exif) = meta.exif {
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if exif.len() > 65_527 {
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return Err(Error::Encode("EXIF larger than one APP1 segment (64 KiB)".into()));
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}
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segs.push((0xE1, [&b"Exif\0\0"[..], exif].concat()));
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}
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if let Some(xmp) = meta.xmp {
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let seg = [XMP_NS, xmp.as_bytes()].concat();
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if seg.len() > 65_533 {
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return Err(Error::Encode("XMP larger than one APP1 segment (extended XMP not supported)".into()));
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}
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segs.push((0xE1, seg));
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}
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if let Some(icc) = meta.icc {
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// ICC.1 Annex B.4: "ICC_PROFILE\0", 1-based chunk number, chunk count
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let chunks: Vec<&[u8]> = icc.chunks(65_519).collect();
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if chunks.len() > 255 {
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return Err(Error::Encode("ICC profile too large for JPEG".into()));
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}
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for (i, c) in chunks.iter().enumerate() {
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segs.push((0xE2, [&b"ICC_PROFILE\0"[..], &[i as u8 + 1, chunks.len() as u8], c].concat()));
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}
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}
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let ch = if img.channels == 2 { 1 } else { img.channels as usize };
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// `data` is already gray for 2-channel input (see above)
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return Ok(crate::jpeg_par::encode(&data, img.width as usize, img.height as usize, ch, quality, subsampling, &segs));
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}
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let mut out = Vec::new();
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let mut enc = jpeg_encoder::Encoder::new(&mut out, quality.clamp(1, 100));
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enc.set_sampling_factor(match subsampling {
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@@ -0,0 +1,495 @@
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//! Parallel baseline JPEG encoder (ITU-T T.81 / JFIF).
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//!
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//! The image is cut into bands of MCU rows separated by restart markers (`DRI` + `RSTn`): DC
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//! prediction restarts at every marker, so bands are entropy-coded independently on all cores and
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//! concatenated. Quantization uses the example tables of T.81 Annex K scaled by the usual 1–100
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//! quality convention; Huffman coding uses the Annex K example tables (interleaved baseline, readable
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//! by every decoder). Supports grayscale and YCbCr 4:4:4 / 4:2:0.
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use crate::encode::ChromaSubsampling;
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/// T.81 Annex K.1 / K.2 example quantization tables (natural order).
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const Q_LUMA: [u16; 64] = [
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16, 11, 10, 16, 24, 40, 51, 61, 12, 12, 14, 19, 26, 58, 60, 55, 14, 13, 16, 24, 40, 57, 69, 56, 14, 17, 22, 29, 51, 87, 80, 62, 18, 22, 37, 56,
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68, 109, 103, 77, 24, 35, 55, 64, 81, 104, 113, 92, 49, 64, 78, 87, 103, 121, 120, 101, 72, 92, 95, 98, 112, 100, 103, 99,
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];
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const Q_CHROMA: [u16; 64] = [
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17, 18, 24, 47, 99, 99, 99, 99, 18, 21, 26, 66, 99, 99, 99, 99, 24, 26, 56, 99, 99, 99, 99, 99, 47, 66, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
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99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
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];
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/// Zig-zag position k → natural index.
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const ZIGZAG: [usize; 64] = [
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0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26, 33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57, 50, 43,
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36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31, 39, 46, 53, 60, 61, 54, 47, 55, 62, 63,
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];
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/// T.81 Annex K.3 example Huffman tables: (code counts per length 1..16, symbols).
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const DC_LUMA_BITS: [u8; 16] = [0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0];
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const DC_CHROMA_BITS: [u8; 16] = [0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0];
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const DC_VALS: [u8; 12] = [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11];
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const AC_LUMA_BITS: [u8; 16] = [0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d];
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const AC_LUMA_VALS: [u8; 162] = [
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0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
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0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
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0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
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0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
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0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
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0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
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0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
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];
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const AC_CHROMA_BITS: [u8; 16] = [0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77];
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const AC_CHROMA_VALS: [u8; 162] = [
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0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
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0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
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0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
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0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
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0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
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0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
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0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
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];
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/// Huffman code table: symbol → (code, length).
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struct Huff {
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code: [(u16, u8); 256],
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}
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impl Huff {
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/// Canonical codes from counts (T.81 Annex C).
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fn new(bits: &[u8; 16], vals: &[u8]) -> Huff {
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let mut code = [(0u16, 0u8); 256];
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let (mut c, mut k) = (0u16, 0usize);
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for (len, &n) in bits.iter().enumerate() {
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for _ in 0..n {
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code[vals[k] as usize] = (c, len as u8 + 1);
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c += 1;
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k += 1;
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}
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c <<= 1;
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}
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Huff { code }
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}
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}
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fn scaled_quant(base: &[u16; 64], quality: u8) -> [u16; 64] {
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let q = quality.clamp(1, 100) as u32;
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let scale = if q < 50 { 5000 / q } else { 200 - 2 * q };
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base.map(|b| ((b as u32 * scale + 50) / 100).clamp(1, 255) as u16)
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}
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/// Entropy-coded segment writer with 0xFF byte stuffing.
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struct Bits {
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out: Vec<u8>,
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acc: u32,
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n: u32,
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}
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impl Bits {
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fn new() -> Bits {
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Bits { out: Vec::new(), acc: 0, n: 0 }
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}
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#[inline]
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fn put(&mut self, code: u32, len: u32) {
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if len == 0 {
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return;
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}
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self.acc = (self.acc << len) | (code & ((1 << len) - 1));
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self.n += len;
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while self.n >= 8 {
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let b = (self.acc >> (self.n - 8)) as u8;
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self.out.push(b);
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if b == 0xFF {
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self.out.push(0);
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}
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self.n -= 8;
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}
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self.acc &= (1 << self.n) - 1;
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}
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/// Pad with 1-bits to a byte boundary.
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fn finish(mut self) -> Vec<u8> {
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if self.n > 0 {
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let pad = 8 - self.n;
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self.put((1 << pad) - 1, pad);
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}
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self.out
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}
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}
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/// AAN output scale factors: `s[0] = 1`, `s[k] = cos(kπ/16)·√2`.
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fn aan_scale() -> [f32; 8] {
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std::array::from_fn(|k| if k == 0 { 1.0 } else { ((k as f64 * std::f64::consts::PI / 16.0).cos() * std::f64::consts::SQRT_2) as f32 })
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}
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/// Quantization reciprocals with the AAN scaling folded in: coefficient = out / (8·s[u]·s[v]·q).
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fn recip_table(q: &[u16; 64]) -> [f32; 64] {
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let s = aan_scale();
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std::array::from_fn(|i| 1.0 / (q[i] as f32 * s[i / 8] * s[i % 8] * 8.0))
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}
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/// One 8-point forward DCT (Arai–Agui–Nakajima flowgraph, 5 multiplies) on `d[o + k·stride]`.
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#[inline(always)]
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fn aan_1d(d: &mut [f32; 64], o: usize, stride: usize) {
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let g = |k: usize| o + k * stride;
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let (t0, t7) = (d[g(0)] + d[g(7)], d[g(0)] - d[g(7)]);
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let (t1, t6) = (d[g(1)] + d[g(6)], d[g(1)] - d[g(6)]);
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let (t2, t5) = (d[g(2)] + d[g(5)], d[g(2)] - d[g(5)]);
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let (t3, t4) = (d[g(3)] + d[g(4)], d[g(3)] - d[g(4)]);
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// even part
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let (t10, t13, t11, t12) = (t0 + t3, t0 - t3, t1 + t2, t1 - t2);
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d[g(0)] = t10 + t11;
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d[g(4)] = t10 - t11;
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let z1 = (t12 + t13) * 0.707_106_77;
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d[g(2)] = t13 + z1;
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d[g(6)] = t13 - z1;
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// odd part
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let (t10, t11, t12) = (t4 + t5, t5 + t6, t6 + t7);
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let z5 = (t10 - t12) * 0.382_683_43;
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let z2 = 0.541_196_1 * t10 + z5;
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let z4 = 1.306_563 * t12 + z5;
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let z3 = t11 * 0.707_106_77;
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let (z11, z13) = (t7 + z3, t7 - z3);
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d[g(5)] = z13 + z2;
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d[g(3)] = z13 - z2;
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d[g(1)] = z11 + z4;
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d[g(7)] = z11 - z4;
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}
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/// Forward DCT of a level-shifted 8×8 block and quantization.
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#[inline]
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fn fdct_quant(block: &[f32; 64], recip: &[f32; 64], out: &mut [i16; 64]) {
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let mut d = *block;
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for r in 0..8 {
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aan_1d(&mut d, r * 8, 1);
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}
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for c in 0..8 {
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aan_1d(&mut d, c, 8);
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}
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for i in 0..64 {
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out[i] = (d[i] * recip[i]).round() as i16;
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}
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}
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#[inline]
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fn magnitude(v: i32) -> (u32, u32) {
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let a = v.unsigned_abs();
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let size = 32 - a.leading_zeros();
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let bits = if v < 0 { (v - 1) as u32 } else { v as u32 };
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(size, bits & ((1u32 << size) - 1))
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}
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fn encode_block(w: &mut Bits, q: &[i16; 64], pred: &mut i32, dc: &Huff, ac: &Huff) {
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let d = q[0] as i32 - *pred;
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*pred = q[0] as i32;
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let (s, b) = magnitude(d);
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let (c, l) = dc.code[s as usize];
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w.put(c as u32, l as u32);
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w.put(b, s);
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let mut run = 0u32;
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for &zi in &ZIGZAG[1..] {
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let v = q[zi] as i32;
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if v == 0 {
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run += 1;
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continue;
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}
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while run >= 16 {
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let (c, l) = ac.code[0xF0];
|
||||
w.put(c as u32, l as u32);
|
||||
run -= 16;
|
||||
}
|
||||
let (s, b) = magnitude(v);
|
||||
let (c, l) = ac.code[((run << 4) | s) as usize];
|
||||
w.put(c as u32, l as u32);
|
||||
w.put(b, s);
|
||||
run = 0;
|
||||
}
|
||||
if run > 0 {
|
||||
let (c, l) = ac.code[0x00];
|
||||
w.put(c as u32, l as u32);
|
||||
}
|
||||
}
|
||||
|
||||
/// Planar component samples (level-shifted to −128..127) with edge replication on read.
|
||||
struct Plane {
|
||||
w: usize,
|
||||
h: usize,
|
||||
data: Vec<f32>,
|
||||
}
|
||||
|
||||
impl Plane {
|
||||
#[inline]
|
||||
fn block(&self, bx: usize, by: usize, out: &mut [f32; 64]) {
|
||||
let (x0, y0) = (bx * 8, by * 8);
|
||||
if x0 + 8 <= self.w && y0 + 8 <= self.h {
|
||||
for y in 0..8 {
|
||||
let i = (y0 + y) * self.w + x0;
|
||||
out[y * 8..y * 8 + 8].copy_from_slice(&self.data[i..i + 8]);
|
||||
}
|
||||
return;
|
||||
}
|
||||
for y in 0..8 {
|
||||
let sy = (by * 8 + y).min(self.h - 1);
|
||||
let row = &self.data[sy * self.w..(sy + 1) * self.w];
|
||||
for x in 0..8 {
|
||||
out[y * 8 + x] = row[(bx * 8 + x).min(self.w - 1)];
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
fn segment(out: &mut Vec<u8>, marker: u8, payload: &[u8]) {
|
||||
out.extend_from_slice(&[0xFF, marker]);
|
||||
out.extend_from_slice(&((payload.len() + 2) as u16).to_be_bytes());
|
||||
out.extend_from_slice(payload);
|
||||
}
|
||||
|
||||
fn dht(out: &mut Vec<u8>, class_id: u8, bits: &[u8; 16], vals: &[u8]) {
|
||||
let mut p = vec![class_id];
|
||||
p.extend_from_slice(bits);
|
||||
p.extend_from_slice(vals);
|
||||
segment(out, 0xC4, &p);
|
||||
}
|
||||
|
||||
/// Encode interleaved 8-bit samples (`channels` 1, 3 or 4; alpha is dropped).
|
||||
pub fn encode(
|
||||
data: &[u8],
|
||||
width: usize,
|
||||
height: usize,
|
||||
channels: usize,
|
||||
quality: u8,
|
||||
sub: ChromaSubsampling,
|
||||
app_segments: &[(u8, Vec<u8>)],
|
||||
) -> Vec<u8> {
|
||||
let gray = channels == 1;
|
||||
let (hs, vs) = match (gray, sub) {
|
||||
(true, _) | (false, ChromaSubsampling::S444) => (1usize, 1usize),
|
||||
(false, _) => (2, 2),
|
||||
};
|
||||
// colour conversion (JFIF YCbCr, full range, level-shifted) in one pass; chroma averaged 2×2 for 4:2:0
|
||||
let n = width * height;
|
||||
#[cfg(feature = "parallel")]
|
||||
use rayon::prelude::*;
|
||||
let ncomp = if gray { 1 } else { 3 };
|
||||
let mut full: Vec<Vec<f32>> = (0..ncomp).map(|_| vec![0f32; n]).collect();
|
||||
{
|
||||
let rows: Vec<(usize, Vec<&mut [f32]>)> = {
|
||||
let mut its: Vec<_> = full.iter_mut().map(|p| p.chunks_mut(width)).collect();
|
||||
(0..height).map(|y| (y, its.iter_mut().map(|it| it.next().unwrap()).collect())).collect()
|
||||
};
|
||||
let conv = |(y, mut out): (usize, Vec<&mut [f32]>)| {
|
||||
let src = &data[y * width * channels..(y + 1) * width * channels];
|
||||
if gray {
|
||||
for (o, p) in out[0].iter_mut().zip(src.chunks_exact(channels)) {
|
||||
*o = p[0] as f32 - 128.0;
|
||||
}
|
||||
return;
|
||||
}
|
||||
for (x, p) in src.chunks_exact(channels).enumerate() {
|
||||
let (r, g, b) = (p[0] as f32, p[1] as f32, p[2] as f32);
|
||||
out[0][x] = 0.299 * r + 0.587 * g + 0.114 * b - 128.0;
|
||||
out[1][x] = -0.168_736 * r - 0.331_264 * g + 0.5 * b;
|
||||
out[2][x] = 0.5 * r - 0.418_688 * g - 0.081_312 * b;
|
||||
}
|
||||
};
|
||||
#[cfg(feature = "parallel")]
|
||||
rows.into_par_iter().for_each(conv);
|
||||
#[cfg(not(feature = "parallel"))]
|
||||
rows.into_iter().for_each(conv);
|
||||
}
|
||||
let mut it = full.into_iter();
|
||||
let mut planes = vec![Plane { w: width, h: height, data: it.next().unwrap_or_default() }];
|
||||
for c in it {
|
||||
if hs == 1 {
|
||||
planes.push(Plane { w: width, h: height, data: c });
|
||||
continue;
|
||||
}
|
||||
let (cw, ch) = (width.div_ceil(2), height.div_ceil(2));
|
||||
let mut d = vec![0f32; cw * ch];
|
||||
let down = |(cy, out): (usize, &mut [f32])| {
|
||||
let (y0, y1) = (2 * cy, (2 * cy + 1).min(height - 1));
|
||||
for (cx, o) in out.iter_mut().enumerate() {
|
||||
let (x0, x1) = (2 * cx, (2 * cx + 1).min(width - 1));
|
||||
*o = 0.25 * (c[y0 * width + x0] + c[y0 * width + x1] + c[y1 * width + x0] + c[y1 * width + x1]);
|
||||
}
|
||||
};
|
||||
#[cfg(feature = "parallel")]
|
||||
d.par_chunks_mut(cw).enumerate().for_each(down);
|
||||
#[cfg(not(feature = "parallel"))]
|
||||
d.chunks_mut(cw).enumerate().for_each(down);
|
||||
planes.push(Plane { w: cw, h: ch, data: d });
|
||||
}
|
||||
|
||||
let ql = scaled_quant(&Q_LUMA, quality);
|
||||
let qc = scaled_quant(&Q_CHROMA, quality);
|
||||
let (rl, rc) = (recip_table(&ql), recip_table(&qc));
|
||||
let (dcl, acl) = (Huff::new(&DC_LUMA_BITS, &DC_VALS), Huff::new(&AC_LUMA_BITS, &AC_LUMA_VALS));
|
||||
let (dcc, acc) = (Huff::new(&DC_CHROMA_BITS, &DC_VALS), Huff::new(&AC_CHROMA_BITS, &AC_CHROMA_VALS));
|
||||
|
||||
let (mcu_w, mcu_h) = (8 * hs, 8 * vs);
|
||||
let (mx, my) = (width.div_ceil(mcu_w), height.div_ceil(mcu_h));
|
||||
// restart interval: whole MCU rows per band, ≤ 65535 MCUs, enough bands to keep all cores busy
|
||||
let rows_per_band = (my / 64).clamp(1, (65_535 / mx.max(1)).max(1));
|
||||
let bands: Vec<usize> = (0..my.div_ceil(rows_per_band)).collect();
|
||||
let encode_band = |band: &usize| -> Vec<u8> {
|
||||
let mut w = Bits::new();
|
||||
let mut pred = [0i32; 3];
|
||||
let (mut blk, mut q) = ([0f32; 64], [0i16; 64]);
|
||||
for mcu_y in band * rows_per_band..((band + 1) * rows_per_band).min(my) {
|
||||
for mcu_x in 0..mx {
|
||||
for vy in 0..vs {
|
||||
for hx in 0..hs {
|
||||
planes[0].block(mcu_x * hs + hx, mcu_y * vs + vy, &mut blk);
|
||||
fdct_quant(&blk, &rl, &mut q);
|
||||
encode_block(&mut w, &q, &mut pred[0], &dcl, &acl);
|
||||
}
|
||||
}
|
||||
if !gray {
|
||||
for k in 1..3 {
|
||||
planes[k].block(mcu_x, mcu_y, &mut blk);
|
||||
fdct_quant(&blk, &rc, &mut q);
|
||||
encode_block(&mut w, &q, &mut pred[k], &dcc, &acc);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
w.finish()
|
||||
};
|
||||
#[cfg(feature = "parallel")]
|
||||
let coded: Vec<Vec<u8>> = bands.par_iter().map(encode_band).collect();
|
||||
#[cfg(not(feature = "parallel"))]
|
||||
let coded: Vec<Vec<u8>> = bands.iter().map(encode_band).collect();
|
||||
|
||||
// headers
|
||||
let mut out = Vec::with_capacity(coded.iter().map(Vec::len).sum::<usize>() + 4096);
|
||||
out.extend_from_slice(&[0xFF, 0xD8]);
|
||||
segment(&mut out, 0xE0, &[b'J', b'F', b'I', b'F', 0, 1, 2, 0, 0, 1, 0, 1, 0, 0]);
|
||||
for (marker, payload) in app_segments {
|
||||
segment(&mut out, *marker, payload);
|
||||
}
|
||||
let dqt = |id: u8, q: &[u16; 64]| -> Vec<u8> {
|
||||
let mut p = vec![id];
|
||||
p.extend(ZIGZAG.iter().map(|&i| q[i] as u8));
|
||||
p
|
||||
};
|
||||
segment(&mut out, 0xDB, &dqt(0, &ql));
|
||||
if !gray {
|
||||
segment(&mut out, 0xDB, &dqt(1, &qc));
|
||||
}
|
||||
let mut sof = vec![8];
|
||||
sof.extend_from_slice(&(height as u16).to_be_bytes());
|
||||
sof.extend_from_slice(&(width as u16).to_be_bytes());
|
||||
if gray {
|
||||
sof.extend_from_slice(&[1, 1, 0x11, 0]);
|
||||
} else {
|
||||
sof.extend_from_slice(&[3, 1, ((hs as u8) << 4) | vs as u8, 0, 2, 0x11, 1, 3, 0x11, 1]);
|
||||
}
|
||||
segment(&mut out, 0xC0, &sof);
|
||||
dht(&mut out, 0x00, &DC_LUMA_BITS, &DC_VALS);
|
||||
dht(&mut out, 0x10, &AC_LUMA_BITS, &AC_LUMA_VALS);
|
||||
if !gray {
|
||||
dht(&mut out, 0x01, &DC_CHROMA_BITS, &DC_VALS);
|
||||
dht(&mut out, 0x11, &AC_CHROMA_BITS, &AC_CHROMA_VALS);
|
||||
}
|
||||
let interval = (rows_per_band * mx) as u16;
|
||||
if coded.len() > 1 {
|
||||
segment(&mut out, 0xDD, &interval.to_be_bytes());
|
||||
}
|
||||
if gray {
|
||||
segment(&mut out, 0xDA, &[1, 1, 0x00, 0, 63, 0]);
|
||||
} else {
|
||||
segment(&mut out, 0xDA, &[3, 1, 0x00, 2, 0x11, 3, 0x11, 0, 63, 0]);
|
||||
}
|
||||
let last = coded.len().saturating_sub(1);
|
||||
for (i, c) in coded.iter().enumerate() {
|
||||
out.extend_from_slice(c);
|
||||
if i < last {
|
||||
out.extend_from_slice(&[0xFF, 0xD0 + (i % 8) as u8]);
|
||||
}
|
||||
}
|
||||
out.extend_from_slice(&[0xFF, 0xD9]);
|
||||
out
|
||||
}
|
||||
|
||||
#[cfg(test)]
|
||||
mod tests {
|
||||
use super::*;
|
||||
|
||||
fn test_rgb(w: usize, h: usize) -> Vec<u8> {
|
||||
let mut v = Vec::with_capacity(w * h * 3);
|
||||
for y in 0..h {
|
||||
for x in 0..w {
|
||||
let t = ((x as f32 / 13.0).sin() * 0.5 + 0.5) * 255.0;
|
||||
v.extend_from_slice(&[(x * 255 / w) as u8, (y * 255 / h) as u8, t as u8]);
|
||||
}
|
||||
}
|
||||
v
|
||||
}
|
||||
|
||||
fn psnr(a: &[u8], b: &[u8]) -> f64 {
|
||||
let mse = a.iter().zip(b).map(|(x, y)| (*x as f64 - *y as f64).powi(2)).sum::<f64>() / a.len() as f64;
|
||||
10.0 * (255.0f64.powi(2) / mse.max(1e-9)).log10()
|
||||
}
|
||||
|
||||
/// The AAN path matches the direct DCT-II definition.
|
||||
#[test]
|
||||
fn aan_matches_reference_dct() {
|
||||
let block: [f32; 64] = std::array::from_fn(|i| ((i * 37 % 255) as f32) - 128.0);
|
||||
let q = [1u16; 64];
|
||||
let mut out = [0i16; 64];
|
||||
fdct_quant(&block, &recip_table(&q), &mut out);
|
||||
for v in 0..8 {
|
||||
for u in 0..8 {
|
||||
let c = |k: usize| if k == 0 { std::f64::consts::FRAC_1_SQRT_2 } else { 1.0 };
|
||||
let mut s = 0.0;
|
||||
for y in 0..8 {
|
||||
for x in 0..8 {
|
||||
s += block[y * 8 + x] as f64
|
||||
* (((2 * x + 1) * u) as f64 * std::f64::consts::PI / 16.0).cos()
|
||||
* (((2 * y + 1) * v) as f64 * std::f64::consts::PI / 16.0).cos();
|
||||
}
|
||||
}
|
||||
let f = 0.25 * c(u) * c(v) * s;
|
||||
assert!((out[v * 8 + u] as f64 - f).abs() <= 0.51, "({u},{v}): {} vs {f}", out[v * 8 + u]);
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn huffman_tables_are_consistent() {
|
||||
for (bits, n) in [(&AC_LUMA_BITS, AC_LUMA_VALS.len()), (&AC_CHROMA_BITS, AC_CHROMA_VALS.len()), (&DC_LUMA_BITS, 12), (&DC_CHROMA_BITS, 12)] {
|
||||
assert_eq!(bits.iter().map(|&b| b as usize).sum::<usize>(), n);
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn decodes_with_independent_decoders_at_odd_sizes() {
|
||||
for (w, h, sub) in [
|
||||
(1, 1, ChromaSubsampling::S444),
|
||||
(37, 23, ChromaSubsampling::S420),
|
||||
(640, 1031, ChromaSubsampling::S420),
|
||||
(803, 600, ChromaSubsampling::S444),
|
||||
] {
|
||||
let src = test_rgb(w, h);
|
||||
let jpg = encode(&src, w, h, 3, 92, sub, &[]);
|
||||
let mut d = jpeg_decoder::Decoder::new(&jpg[..]);
|
||||
let px = d.decode().expect("jpeg-decoder");
|
||||
let info = d.info().unwrap();
|
||||
assert_eq!((info.width as usize, info.height as usize), (w, h));
|
||||
if w * h > 64 {
|
||||
assert!(psnr(&src, &px) > 30.0, "{w}x{h} {sub:?}: psnr {}", psnr(&src, &px));
|
||||
}
|
||||
let z = zune_jpeg::JpegDecoder::new(zune_core::bytestream::ZCursor::new(&jpg[..])).decode().expect("zune-jpeg");
|
||||
assert_eq!(z.len(), px.len());
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn grayscale_and_quality_monotone() {
|
||||
let (w, h) = (300, 200);
|
||||
let src: Vec<u8> = (0..w * h).map(|i| ((i % w) * 255 / w) as u8 ^ ((i / w) as u8 & 0x10)).collect();
|
||||
let lo = encode(&src, w, h, 1, 30, ChromaSubsampling::S444, &[]);
|
||||
let hi = encode(&src, w, h, 1, 95, ChromaSubsampling::S444, &[]);
|
||||
assert!(lo.len() < hi.len());
|
||||
let px = jpeg_decoder::Decoder::new(&hi[..]).decode().unwrap();
|
||||
assert!(psnr(&src, &px) > 35.0);
|
||||
}
|
||||
}
|
||||
@@ -18,6 +18,7 @@ pub mod encode;
|
||||
pub mod exif;
|
||||
pub mod icc;
|
||||
mod jpeg;
|
||||
pub mod jpeg_par;
|
||||
#[cfg(feature = "jxl")]
|
||||
mod jxl;
|
||||
mod other;
|
||||
|
||||
Reference in new issue
Block a user