exr/compression/b44/
mod.rs

1mod table;
2
3use crate::compression::{mod_p, ByteVec};
4use crate::error::usize_to_i32;
5use crate::io::Data;
6use crate::meta::attribute::ChannelList;
7use crate::prelude::*;
8use std::cmp::min;
9use std::mem::size_of;
10use table::{EXP_TABLE, LOG_TABLE};
11use lebe::io::{ReadPrimitive, WriteEndian};
12
13const BLOCK_SAMPLE_COUNT: usize = 4;
14
15// As B44 compression is only use on f16 channels, we can have a conste for this value.
16const BLOCK_X_BYTE_COUNT: usize = BLOCK_SAMPLE_COUNT * size_of::<u16>();
17
18#[inline]
19fn convert_from_linear(s: &mut [u16; 16]) {
20    for v in s {
21        *v = EXP_TABLE[*v as usize];
22    }
23}
24
25#[inline]
26fn convert_to_linear(s: &mut [u16; 16]) {
27    for v in s {
28        *v = LOG_TABLE[*v as usize];
29    }
30}
31
32#[inline]
33fn shift_and_round(x: i32, shift: i32) -> i32 {
34    let x = x << 1;
35    let a = (1 << shift) - 1;
36    let shift = shift + 1;
37    let b = (x >> shift) & 1;
38    (x + a + b) >> shift
39}
40
41/// Pack a block of 4 by 4 16-bit pixels (32 bytes, the array `s`) into either 14 or 3 bytes.
42fn pack(s: [u16; 16], b: &mut [u8], optimize_flat_fields: bool, exact_max: bool) -> usize {
43
44    let mut t = [0u16; 16];
45
46    for i in 0..16 {
47        if (s[i] & 0x7c00) == 0x7c00 {
48            t[i] = 0x8000;
49        } else if (s[i] & 0x8000) != 0 {
50            t[i] = !s[i];
51        } else {
52            t[i] = s[i] | 0x8000;
53        }
54    }
55
56    let t_max = t.iter().max().unwrap();
57
58    // Compute a set of running differences, r[0] ... r[14]:
59    // Find a shift value such that after rounding off the
60    // rightmost bits and shifting all differences are between
61    // -32 and +31.  Then bias the differences so that they
62    // end up between 0 and 63.
63    let mut shift = -1;
64    let mut d = [0i32; 16];
65    let mut r = [0i32; 15];
66    let mut r_min: i32;
67    let mut r_max: i32;
68
69    const BIAS: i32 = 0x20;
70
71    loop {
72        shift += 1;
73
74        // Compute absolute differences, d[0] ... d[15],
75        // between t_max and t[0] ... t[15].
76        //
77        // Shift and round the absolute differences.
78        d.iter_mut()
79            .zip(&t)
80            .for_each(|(d_v, t_v)| *d_v = shift_and_round((t_max - t_v).into(), shift));
81
82        // Convert d[0] .. d[15] into running differences
83        r[0] = d[0] - d[4] + BIAS;
84        r[1] = d[4] - d[8] + BIAS;
85        r[2] = d[8] - d[12] + BIAS;
86
87        r[3] = d[0] - d[1] + BIAS;
88        r[4] = d[4] - d[5] + BIAS;
89        r[5] = d[8] - d[9] + BIAS;
90        r[6] = d[12] - d[13] + BIAS;
91
92        r[7] = d[1] - d[2] + BIAS;
93        r[8] = d[5] - d[6] + BIAS;
94        r[9] = d[9] - d[10] + BIAS;
95        r[10] = d[13] - d[14] + BIAS;
96
97        r[11] = d[2] - d[3] + BIAS;
98        r[12] = d[6] - d[7] + BIAS;
99        r[13] = d[10] - d[11] + BIAS;
100        r[14] = d[14] - d[15] + BIAS;
101
102        r_min = r[0];
103        r_max = r[0];
104
105        r.iter().copied().for_each(|v| {
106            if r_min > v {
107                r_min = v;
108            }
109
110            if r_max < v {
111                r_max = v;
112            }
113        });
114
115        if !(r_min < 0 || r_max > 0x3f) {
116            break;
117        }
118    }
119
120    if r_min == BIAS && r_max == BIAS && optimize_flat_fields {
121        // Special case - all pixels have the same value.
122        // We encode this in 3 instead of 14 bytes by
123        // storing the value 0xfc in the third output byte,
124        // which cannot occur in the 14-byte encoding.
125        b[0] = (t[0] >> 8) as u8;
126        b[1] = t[0] as u8;
127        b[2] = 0xfc;
128
129        return 3;
130    }
131
132    if exact_max {
133        // Adjust t[0] so that the pixel whose value is equal
134        // to t_max gets represented as accurately as possible.
135        t[0] = t_max - (d[0] << shift) as u16;
136    }
137
138    // Pack t[0], shift and r[0] ... r[14] into 14 bytes:
139    b[0] = (t[0] >> 8) as u8;
140    b[1] = t[0] as u8;
141
142    b[2] = ((shift << 2) | (r[0] >> 4)) as u8;
143    b[3] = ((r[0] << 4) | (r[1] >> 2)) as u8;
144    b[4] = ((r[1] << 6) | r[2]) as u8;
145
146    b[5] = ((r[3] << 2) | (r[4] >> 4)) as u8;
147    b[6] = ((r[4] << 4) | (r[5] >> 2)) as u8;
148    b[7] = ((r[5] << 6) | r[6]) as u8;
149
150    b[8] = ((r[7] << 2) | (r[8] >> 4)) as u8;
151    b[9] = ((r[8] << 4) | (r[9] >> 2)) as u8;
152    b[10] = ((r[9] << 6) | r[10]) as u8;
153
154    b[11] = ((r[11] << 2) | (r[12] >> 4)) as u8;
155    b[12] = ((r[12] << 4) | (r[13] >> 2)) as u8;
156    b[13] = ((r[13] << 6) | r[14]) as u8;
157
158    return 14;
159}
160
161// Tiny macro to simply get block array value as a u32.
162macro_rules! b32 {
163    ($b:expr, $i:expr) => {
164        $b[$i] as u32
165    };
166}
167
168// 0011 1111
169const SIX_BITS: u32 = 0x3f;
170
171// Unpack a 14-byte block into 4 by 4 16-bit pixels.
172fn unpack14(b: &[u8], s: &mut [u16; 16]) {
173    debug_assert_eq!(b.len(), 14);
174    debug_assert_ne!(b[2], 0xfc);
175
176    s[0] = ((b32!(b, 0) << 8) | b32!(b, 1)) as u16;
177
178    let shift = b32!(b, 2) >> 2;
179    let bias = 0x20 << shift;
180
181    s[4] = (s[0] as u32 + ((((b32!(b, 2) << 4) | (b32!(b, 3) >> 4)) & SIX_BITS) << shift) - bias) as u16;
182    s[8] = (s[4] as u32 + ((((b32!(b, 3) << 2) | (b32!(b, 4) >> 6)) & SIX_BITS) << shift) - bias) as u16;
183    s[12] = (s[8] as u32 + ((b32!(b, 4) & SIX_BITS) << shift) - bias) as u16;
184
185    s[1] = (s[0] as u32 + ((b32!(b, 5) >> 2) << shift) - bias) as u16;
186    s[5] = (s[4] as u32 + ((((b32!(b, 5) << 4) | (b32!(b, 6) >> 4)) & SIX_BITS) << shift) - bias) as u16;
187    s[9] = (s[8] as u32 + ((((b32!(b, 6) << 2) | (b32!(b, 7) >> 6)) & SIX_BITS) << shift) - bias) as u16;
188    s[13] = (s[12] as u32 + ((b32!(b, 7) & SIX_BITS) << shift) - bias) as u16;
189
190    s[2] = (s[1] as u32 + ((b32!(b, 8) >> 2) << shift) - bias) as u16;
191    s[6] = (s[5] as u32 + ((((b32!(b, 8) << 4) | (b32!(b, 9) >> 4)) & SIX_BITS) << shift)  - bias) as u16;
192    s[10] = (s[9] as u32 + ((((b32!(b, 9) << 2) | (b32!(b, 10) >> 6)) & SIX_BITS) << shift) - bias) as u16;
193    s[14] = (s[13] as u32 + ((b32!(b, 10) & SIX_BITS) << shift) - bias) as u16;
194
195    s[3] = (s[2] as u32 + ((b32!(b, 11) >> 2) << shift) - bias) as u16;
196    s[7] = (s[6] as u32 + ((((b32!(b, 11) << 4) | (b32!(b, 12) >> 4)) & SIX_BITS) << shift) - bias) as u16;
197    s[11] = (s[10] as u32 + ((((b32!(b, 12) << 2) | (b32!(b, 13) >> 6)) & SIX_BITS) << shift) - bias) as u16;
198    s[15] = (s[14] as u32 + ((b32!(b, 13) & SIX_BITS) << shift) - bias) as u16;
199
200    for i in 0..16 {
201        if (s[i] & 0x8000) != 0 {
202            s[i] &= 0x7fff;
203        } else {
204            s[i] = !s[i];
205        }
206    }
207}
208
209// Unpack a 3-byte block `b` into 4 by 4 identical 16-bit pixels in `s` array.
210fn unpack3(b: &[u8], s: &mut [u16; 16]) {
211    // this assertion panics for fuzzed images.
212    // assuming this debug assertion is an overly strict check to catch potential compression errors.
213    // disabling because it panics when fuzzed.
214    // when commenting out, it simply works (maybe it should return an error instead?).
215    // debug_assert_eq!(b[2], 0xfc);
216
217    // Get the 16-bit value from the block.
218    let mut value = ((b32!(b, 0) << 8) | b32!(b, 1)) as u16;
219
220    if (value & 0x8000) != 0 {
221        value &= 0x7fff;
222    } else {
223        value = !value;
224    }
225
226    s.fill(value); // All pixels have save value.
227}
228
229#[derive(Debug)]
230struct ChannelData {
231    tmp_start_index: usize,
232    tmp_end_index: usize,
233    resolution: Vec2<usize>,
234    y_sampling: usize,
235    sample_type: SampleType,
236    quantize_linearly: bool,
237    samples_per_pixel: usize,
238}
239
240// TODO: Unsafe seems to be required to efficiently copy whole slice of u16 ot u8. For now, we use
241//   a less efficient, yet safe, implementation.
242#[inline]
243fn memcpy_u16_to_u8(src: &[u16], mut dst: &mut [u8]) {
244    use lebe::prelude::*;
245    dst.write_as_native_endian(src).expect("byte copy error");
246}
247
248#[inline]
249fn memcpy_u8_to_u16(mut src: &[u8], dst: &mut [u16]) {
250    use lebe::prelude::*;
251    src.read_from_native_endian_into(dst).expect("byte copy error");
252}
253
254#[inline]
255fn cpy_u8(src: &[u16], src_i: usize, dst: &mut [u8], dst_i: usize, n: usize) {
256    memcpy_u16_to_u8(&src[src_i..src_i + n], &mut dst[dst_i..dst_i + 2 * n]);
257}
258
259pub fn decompress(
260    channels: &ChannelList,
261    compressed: ByteVec,
262    rectangle: IntegerBounds,
263    expected_byte_size: usize,
264    _pedantic: bool,
265) -> Result<ByteVec> {
266    debug_assert_eq!(
267        expected_byte_size,
268        rectangle.size.area() * channels.bytes_per_pixel,
269        "expected byte size does not match header" // TODO compute instead of passing argument?
270    );
271
272    debug_assert!(!channels.list.is_empty(), "no channels found");
273
274    if compressed.is_empty() {
275        return Ok(Vec::new());
276    }
277
278    // Extract channel information needed for decompression.
279    let mut channel_data: Vec<ChannelData> = Vec::with_capacity(channels.list.len());
280    let mut tmp_read_index = 0;
281
282    for channel in channels.list.iter() {
283        let channel = ChannelData {
284            tmp_start_index: tmp_read_index,
285            tmp_end_index: tmp_read_index,
286            resolution: channel.subsampled_resolution(rectangle.size),
287            y_sampling: channel.sampling.y(),
288            sample_type: channel.sample_type,
289            quantize_linearly: channel.quantize_linearly,
290            samples_per_pixel: channel.sampling.area(),
291        };
292
293        tmp_read_index += channel.resolution.area()
294            * channel.samples_per_pixel
295            * channel.sample_type.bytes_per_sample();
296
297        channel_data.push(channel);
298    }
299
300    // Temporary buffer is used to decompress B44 datas the way they are stored in the compressed
301    // buffer (channel by channel). We interleave the final result later.
302    let mut tmp = Vec::with_capacity(expected_byte_size);
303
304    // Index in the compressed buffer.
305    let mut in_i = 0usize;
306
307    let mut remaining = compressed.len();
308
309    for channel in &channel_data {
310
311        debug_assert_eq!(remaining, compressed.len()-in_i);
312
313        // Compute information for current channel.
314        let sample_count = channel.resolution.area() * channel.samples_per_pixel;
315        let byte_count = sample_count * channel.sample_type.bytes_per_sample();
316
317        // Sample types that does not support B44 compression (u32 and f32) are raw copied.
318        // In this branch, "compressed" array is actually raw, uncompressed data.
319        if channel.sample_type != SampleType::F16 {
320
321            debug_assert_eq!(channel.sample_type.bytes_per_sample(), 4);
322
323            if remaining < byte_count {
324                return Err(Error::invalid("not enough data"));
325            }
326
327            tmp.extend_from_slice(&compressed[in_i..(in_i + byte_count)]);
328
329            in_i += byte_count;
330            remaining -= byte_count;
331
332            continue;
333        }
334
335        // HALF channel
336        // The rest of the code assume we are manipulating u16 (2 bytes) values.
337        debug_assert_eq!(channel.sample_type, SampleType::F16);
338        debug_assert_eq!(channel.sample_type.bytes_per_sample(), size_of::<u16>());
339
340        // Increase buffer to get new uncompressed datas.
341        tmp.resize(tmp.len() + byte_count, 0);
342
343        let x_sample_count = channel.resolution.x() * channel.samples_per_pixel;
344        let y_sample_count = channel.resolution.y() * channel.samples_per_pixel;
345
346        let bytes_per_sample = size_of::<u16>();
347
348        let x_byte_count = x_sample_count * bytes_per_sample;
349        let cd_start = channel.tmp_start_index;
350
351        for y in (0..y_sample_count).step_by(BLOCK_SAMPLE_COUNT) {
352            // Compute index in output (decompressed) buffer. We have 4 rows, because we will
353            // uncompress 4 by 4 data blocks.
354            let mut row0 = cd_start + y * x_byte_count;
355            let mut row1 = row0 + x_byte_count;
356            let mut row2 = row1 + x_byte_count;
357            let mut row3 = row2 + x_byte_count;
358
359            // Move in pixel x line, 4 by 4.
360            for x in (0..x_sample_count).step_by(BLOCK_SAMPLE_COUNT) {
361
362                // Extract the 4 by 4 block of 16-bit floats from the compressed buffer.
363                let mut s = [0u16; 16];
364
365                if remaining < 3 {
366                    return Err(Error::invalid("not enough data"));
367                }
368
369                // If shift exponent is 63, call unpack14 (ignoring unused bits)
370                if compressed[in_i + 2] >= (13 << 2) {
371                    if remaining < 3 {
372                        return Err(Error::invalid("not enough data"));
373                    }
374
375                    unpack3(&compressed[in_i..(in_i + 3)], &mut s);
376
377                    in_i += 3;
378                    remaining -= 3;
379                } else {
380                    if remaining < 14 {
381                        return Err(Error::invalid("not enough data"));
382                    }
383
384                    unpack14(&compressed[in_i..(in_i + 14)], &mut s);
385
386                    in_i += 14;
387                    remaining -= 14;
388                }
389
390                if channel.quantize_linearly {
391                    convert_to_linear(&mut s);
392                }
393
394                // Get resting samples from the line to copy in temp buffer (without going outside channel).
395                let x_resting_sample_count = match x + 3 < x_sample_count {
396                    true => BLOCK_SAMPLE_COUNT,
397                    false => x_sample_count - x,
398                };
399
400                debug_assert!(x_resting_sample_count > 0);
401                debug_assert!(x_resting_sample_count <= BLOCK_SAMPLE_COUNT);
402
403                // Copy rows (without going outside channel).
404                if y + 3 < y_sample_count {
405                    cpy_u8(&s, 0, &mut tmp, row0, x_resting_sample_count);
406                    cpy_u8(&s, 4, &mut tmp, row1, x_resting_sample_count);
407                    cpy_u8(&s, 8, &mut tmp, row2, x_resting_sample_count);
408                    cpy_u8(&s, 12, &mut tmp, row3, x_resting_sample_count);
409                } else {
410                    debug_assert!(y < y_sample_count);
411
412                    cpy_u8(&s, 0, &mut tmp, row0, x_resting_sample_count);
413
414                    if y + 1 < y_sample_count {
415                        cpy_u8(&s, 4, &mut tmp, row1, x_resting_sample_count);
416                    }
417
418                    if y + 2 < y_sample_count {
419                        cpy_u8(&s, 8, &mut tmp, row2, x_resting_sample_count);
420                    }
421                }
422
423                // Update row's array index to 4 next pixels.
424                row0 += BLOCK_X_BYTE_COUNT;
425                row1 += BLOCK_X_BYTE_COUNT;
426                row2 += BLOCK_X_BYTE_COUNT;
427                row3 += BLOCK_X_BYTE_COUNT;
428            }
429        }
430    }
431
432    debug_assert_eq!(tmp.len(), expected_byte_size);
433
434    // Interleave uncompressed channel data.
435    let mut out = Vec::with_capacity(expected_byte_size);
436
437    for y in rectangle.position.y()..rectangle.end().y() {
438        for channel in &mut channel_data {
439            if mod_p(y, usize_to_i32(channel.y_sampling)) != 0 {
440                continue;
441            }
442
443            // Find data location in temporary buffer.
444            let x_sample_count = channel.resolution.x() * channel.samples_per_pixel;
445            let bytes_per_line = x_sample_count * channel.sample_type.bytes_per_sample();
446            let next_tmp_end_index = channel.tmp_end_index + bytes_per_line;
447            let channel_bytes = &tmp[channel.tmp_end_index..next_tmp_end_index];
448
449            channel.tmp_end_index = next_tmp_end_index;
450
451            // TODO do not convert endianness for f16-only images
452            //      see https://github.com/AcademySoftwareFoundation/openexr/blob/3bd93f85bcb74c77255f28cdbb913fdbfbb39dfe/OpenEXR/IlmImf/ImfTiledOutputFile.cpp#L750-L842
453            // We can support uncompressed data in the machine's native format
454            // if all image channels are of type HALF, and if the Xdr and the
455            // native representations of a half have the same size.
456
457            if channel.sample_type == SampleType::F16 {
458                // TODO simplify this and make it memcpy on little endian systems
459                // https://github.com/AcademySoftwareFoundation/openexr/blob/a03aca31fa1ce85d3f28627dbb3e5ded9494724a/src/lib/OpenEXR/ImfB44Compressor.cpp#L943
460                for mut f16_bytes in channel_bytes.chunks(std::mem::size_of::<f16>()) {
461                    let native_endian_f16_bits = u16::read_from_little_endian(&mut f16_bytes).expect("memory read failed");
462                    out.write_as_native_endian(&native_endian_f16_bits).expect("memory write failed");
463                }
464            }
465            else {
466                u8::write_slice(&mut out, channel_bytes)
467                    .expect("write to in-memory failed");
468            }
469        }
470    }
471
472    for index in 1..channel_data.len() {
473        debug_assert_eq!(
474            channel_data[index - 1].tmp_end_index,
475            channel_data[index].tmp_start_index
476        );
477    }
478
479    debug_assert_eq!(out.len(), expected_byte_size);
480
481    // TODO do not convert endianness for f16-only images
482    //      see https://github.com/AcademySoftwareFoundation/openexr/blob/3bd93f85bcb74c77255f28cdbb913fdbfbb39dfe/OpenEXR/IlmImf/ImfTiledOutputFile.cpp#L750-L842
483    Ok(super::convert_little_endian_to_current(out, channels, rectangle))
484}
485
486pub fn compress(
487    channels: &ChannelList,
488    uncompressed: ByteVec,
489    rectangle: IntegerBounds,
490    optimize_flat_fields: bool,
491) -> Result<ByteVec> {
492    if uncompressed.is_empty() {
493        return Ok(Vec::new());
494    }
495
496    // TODO do not convert endianness for f16-only images
497    //      see https://github.com/AcademySoftwareFoundation/openexr/blob/3bd93f85bcb74c77255f28cdbb913fdbfbb39dfe/OpenEXR/IlmImf/ImfTiledOutputFile.cpp#L750-L842
498    let uncompressed = super::convert_current_to_little_endian(uncompressed, channels, rectangle);
499    let uncompressed = uncompressed.as_slice(); // TODO no alloc
500
501    let mut channel_data = Vec::new();
502
503    let mut tmp_end_index = 0;
504    for channel in &channels.list {
505        let number_samples = channel.subsampled_resolution(rectangle.size);
506
507        let sample_count = channel.subsampled_resolution(rectangle.size).area();
508        let byte_count = sample_count * channel.sample_type.bytes_per_sample();
509
510        let channel = ChannelData {
511            tmp_start_index: tmp_end_index,
512            tmp_end_index,
513            y_sampling: channel.sampling.y(),
514            resolution: number_samples,
515            sample_type: channel.sample_type,
516            quantize_linearly: channel.quantize_linearly,
517            samples_per_pixel: channel.sampling.area(),
518        };
519
520        tmp_end_index += byte_count;
521        channel_data.push(channel);
522    }
523
524    let mut tmp = vec![0_u8; uncompressed.len()];
525
526    debug_assert_eq!(tmp_end_index, tmp.len());
527
528    let mut remaining_uncompressed_bytes = uncompressed;
529
530    for y in rectangle.position.y()..rectangle.end().y() {
531        for channel in &mut channel_data {
532            if mod_p(y, usize_to_i32(channel.y_sampling)) != 0 {
533                continue;
534            }
535
536            let x_sample_count = channel.resolution.x() * channel.samples_per_pixel;
537            let bytes_per_line = x_sample_count * channel.sample_type.bytes_per_sample();
538            let next_tmp_end_index = channel.tmp_end_index + bytes_per_line;
539            let target = &mut tmp[channel.tmp_end_index..next_tmp_end_index];
540
541            channel.tmp_end_index = next_tmp_end_index;
542
543            // TODO do not convert endianness for f16-only images
544            //      see https://github.com/AcademySoftwareFoundation/openexr/blob/3bd93f85bcb74c77255f28cdbb913fdbfbb39dfe/OpenEXR/IlmImf/ImfTiledOutputFile.cpp#L750-L842
545            // We can support uncompressed data in the machine's native format
546            // if all image channels are of type HALF, and if the Xdr and the
547            // native representations of a half have the same size.
548
549            if channel.sample_type == SampleType::F16 {
550
551                // TODO simplify this and make it memcpy on little endian systems
552                // https://github.com/AcademySoftwareFoundation/openexr/blob/a03aca31fa1ce85d3f28627dbb3e5ded9494724a/src/lib/OpenEXR/ImfB44Compressor.cpp#L640
553
554                for mut out_f16_bytes in target.chunks_mut(2) {
555                    let native_endian_f16_bits = u16::read_from_native_endian(&mut remaining_uncompressed_bytes).expect("memory read failed");
556                    out_f16_bytes.write_as_little_endian(&native_endian_f16_bits).expect("memory write failed");
557                }
558            }
559            else {
560                u8::read_slice(&mut remaining_uncompressed_bytes, target)
561                    .expect("in-memory read failed");
562            }
563        }
564    }
565
566    // Generate a whole buffer that we will crop to proper size once compression is done.
567    let mut b44_compressed = vec![0; std::cmp::max(2048, uncompressed.len())];
568    let mut b44_end = 0; // Buffer byte index for storing next compressed values.
569
570    for channel in &channel_data {
571        // U32 and F32 channels are raw copied.
572        if channel.sample_type != SampleType::F16 {
573
574            debug_assert_eq!(channel.sample_type.bytes_per_sample(), 4);
575
576            // Raw byte copy.
577            let slice = &tmp[channel.tmp_start_index..channel.tmp_end_index];
578            slice.iter().copied().for_each(|b| {
579                b44_compressed[b44_end] = b;
580                b44_end += 1;
581            });
582
583            continue;
584        }
585
586        // HALF channel
587        debug_assert_eq!(channel.sample_type, SampleType::F16);
588        debug_assert_eq!(channel.sample_type.bytes_per_sample(), size_of::<u16>());
589
590        let x_sample_count = channel.resolution.x() * channel.samples_per_pixel;
591        let y_sample_count = channel.resolution.y() * channel.samples_per_pixel;
592
593        let x_byte_count = x_sample_count * size_of::<u16>();
594        let cd_start = channel.tmp_start_index;
595
596        for y in (0..y_sample_count).step_by(BLOCK_SAMPLE_COUNT) {
597            //
598            // Copy the next 4x4 pixel block into array s.
599            // If the width, cd.nx, or the height, cd.ny, of
600            // the pixel data in _tmpBuffer is not divisible
601            // by 4, then pad the data by repeating the
602            // rightmost column and the bottom row.
603            //
604
605            // Compute row index in temp buffer.
606            let mut row0 = cd_start + y * x_byte_count;
607            let mut row1 = row0 + x_byte_count;
608            let mut row2 = row1 + x_byte_count;
609            let mut row3 = row2 + x_byte_count;
610
611            if y + 3 >= y_sample_count {
612                if y + 1 >= y_sample_count {
613                    row1 = row0;
614                }
615
616                if y + 2 >= y_sample_count {
617                    row2 = row1;
618                }
619
620                row3 = row2;
621            }
622
623            for x in (0..x_sample_count).step_by(BLOCK_SAMPLE_COUNT) {
624                let mut s = [0u16; 16];
625
626                if x + 3 >= x_sample_count {
627                    let n = x_sample_count - x;
628
629                    for i in 0..BLOCK_SAMPLE_COUNT {
630                        let j = min(i, n - 1) * 2;
631
632                        // TODO: Make [u8; 2] to u16 fast.
633                        s[i + 0] = u16::from_ne_bytes([tmp[row0 + j], tmp[row0 + j + 1]]);
634                        s[i + 4] = u16::from_ne_bytes([tmp[row1 + j], tmp[row1 + j + 1]]);
635                        s[i + 8] = u16::from_ne_bytes([tmp[row2 + j], tmp[row2 + j + 1]]);
636                        s[i + 12] = u16::from_ne_bytes([tmp[row3 + j], tmp[row3 + j + 1]]);
637                    }
638                } else {
639                    memcpy_u8_to_u16(&tmp[row0..(row0 + BLOCK_X_BYTE_COUNT)], &mut s[0..4]);
640                    memcpy_u8_to_u16(&tmp[row1..(row1 + BLOCK_X_BYTE_COUNT)], &mut s[4..8]);
641                    memcpy_u8_to_u16(&tmp[row2..(row2 + BLOCK_X_BYTE_COUNT)], &mut s[8..12]);
642                    memcpy_u8_to_u16(&tmp[row3..(row3 + BLOCK_X_BYTE_COUNT)], &mut s[12..16]);
643                }
644
645                // Move to next block.
646                row0 += BLOCK_X_BYTE_COUNT;
647                row1 += BLOCK_X_BYTE_COUNT;
648                row2 += BLOCK_X_BYTE_COUNT;
649                row3 += BLOCK_X_BYTE_COUNT;
650
651                // Compress the contents of array `s` and append the results to the output buffer.
652                if channel.quantize_linearly {
653                    convert_from_linear(&mut s);
654                }
655
656                b44_end += pack(
657                    s,
658                    &mut b44_compressed[b44_end..(b44_end + 14)],
659                    optimize_flat_fields,
660                    !channel.quantize_linearly,
661                );
662            }
663        }
664    }
665
666    b44_compressed.resize(b44_end, 0);
667
668    Ok(b44_compressed)
669}
670
671#[cfg(test)]
672mod test {
673    use crate::compression::b44;
674    use crate::compression::b44::{convert_from_linear, convert_to_linear};
675    use crate::compression::ByteVec;
676    use crate::image::validate_results::ValidateResult;
677    use crate::meta::attribute::ChannelList;
678    use crate::prelude::f16;
679    use crate::prelude::*;
680
681    #[test]
682    fn test_convert_from_to_linear() {
683        // Create two identical arrays with random floats.
684        let mut s1 = [0u16; 16];
685
686        for i in 0..16 {
687            s1[i] = f16::from_f32(rand::random::<f32>()).to_bits();
688        }
689
690        let s2 = s1.clone();
691
692        // Apply two reversible conversion.
693        convert_from_linear(&mut s1);
694        convert_to_linear(&mut s1);
695
696        // And check.
697        for (u1, u2) in s1.iter().zip(&s2) {
698            let f1 = f16::from_bits(*u1).to_f64();
699            let f2 = f16::from_bits(*u2).to_f64();
700            assert!((f1 - f2).abs() < 0.01);
701        }
702    }
703
704    fn test_roundtrip_noise_with(
705        channels: ChannelList,
706        rectangle: IntegerBounds,
707    ) -> (ByteVec, ByteVec, ByteVec) {
708        let byte_count = channels
709            .list
710            .iter()
711            .map(|c| {
712                c.subsampled_resolution(rectangle.size).area() * c.sample_type.bytes_per_sample()
713            })
714            .sum();
715
716        assert!(byte_count > 0);
717
718        let pixel_bytes: ByteVec = (0..byte_count).map(|_| rand::random()).collect();
719
720        assert_eq!(pixel_bytes.len(), byte_count);
721
722        let compressed = b44::compress(&channels, pixel_bytes.clone(), rectangle, true).unwrap();
723
724        let decompressed =
725            b44::decompress(&channels, compressed.clone(), rectangle, pixel_bytes.len(), true).unwrap();
726
727        assert_eq!(decompressed.len(), pixel_bytes.len());
728
729        (pixel_bytes, compressed, decompressed)
730    }
731
732    #[test]
733    fn roundtrip_noise_f16() {
734        let channel = ChannelDescription {
735            sample_type: SampleType::F16,
736            name: Default::default(),
737            quantize_linearly: false,
738            sampling: Vec2(1, 1),
739        };
740
741        // Two similar channels.
742        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
743
744        let rectangle = IntegerBounds {
745            position: Vec2(-30, 100),
746            size: Vec2(322, 731),
747        };
748
749        let (pixel_bytes, compressed, decompressed) =
750            test_roundtrip_noise_with(channels, rectangle);
751
752        // On my tests, B44 give a size of 44.08% the original data (this assert implies enough
753        // pixels to be relevant).
754        assert_eq!(pixel_bytes.len(), 941528);
755        assert_eq!(compressed.len(), 415044);
756        assert_eq!(decompressed.len(), 941528);
757    }
758
759    #[test]
760    fn roundtrip_noise_f16_tiny() {
761        let channel = ChannelDescription {
762            sample_type: SampleType::F16,
763            name: Default::default(),
764            quantize_linearly: false,
765            sampling: Vec2(1, 1),
766        };
767
768        // Two similar channels.
769        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
770
771        let rectangle = IntegerBounds {
772            position: Vec2(0, 0),
773            size: Vec2(3, 2),
774        };
775
776        let (pixel_bytes, compressed, decompressed) =
777            test_roundtrip_noise_with(channels, rectangle);
778
779        // B44 being 4 by 4 block, compression is less efficient for tiny images.
780        assert_eq!(pixel_bytes.len(), 24);
781        assert_eq!(compressed.len(), 28);
782        assert_eq!(decompressed.len(), 24);
783    }
784
785    #[test]
786    fn roundtrip_noise_f32() {
787        let channel = ChannelDescription {
788            sample_type: SampleType::F32,
789            name: Default::default(),
790            quantize_linearly: false,
791            sampling: Vec2(1, 1),
792        };
793
794        // Two similar channels.
795        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
796
797        let rectangle = IntegerBounds {
798            position: Vec2(-30, 100),
799            size: Vec2(322, 731),
800        };
801
802        let (pixel_bytes, compressed, decompressed) =
803            test_roundtrip_noise_with(channels, rectangle);
804
805        assert_eq!(pixel_bytes.len(), 1883056);
806        assert_eq!(compressed.len(), 1883056);
807        assert_eq!(decompressed.len(), 1883056);
808        assert_eq!(pixel_bytes, decompressed);
809    }
810
811    #[test]
812    fn roundtrip_noise_f32_tiny() {
813        let channel = ChannelDescription {
814            sample_type: SampleType::F32,
815            name: Default::default(),
816            quantize_linearly: false,
817            sampling: Vec2(1, 1),
818        };
819
820        // Two similar channels.
821        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
822
823        let rectangle = IntegerBounds {
824            position: Vec2(0, 0),
825            size: Vec2(3, 2),
826        };
827
828        let (pixel_bytes, compressed, decompressed) =
829            test_roundtrip_noise_with(channels, rectangle);
830
831        assert_eq!(pixel_bytes.len(), 48);
832        assert_eq!(compressed.len(), 48);
833        assert_eq!(decompressed.len(), 48);
834        assert_eq!(pixel_bytes, decompressed);
835    }
836
837    #[test]
838    fn roundtrip_noise_u32() {
839        let channel = ChannelDescription {
840            sample_type: SampleType::U32,
841            name: Default::default(),
842            quantize_linearly: false,
843            sampling: Vec2(1, 1),
844        };
845
846        // Two similar channels.
847        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
848
849        let rectangle = IntegerBounds {
850            position: Vec2(-30, 100),
851            size: Vec2(322, 731),
852        };
853
854        let (pixel_bytes, compressed, decompressed) =
855            test_roundtrip_noise_with(channels, rectangle);
856
857        assert_eq!(pixel_bytes.len(), 1883056);
858        assert_eq!(compressed.len(), 1883056);
859        assert_eq!(decompressed.len(), 1883056);
860        assert_eq!(pixel_bytes, decompressed);
861    }
862
863    #[test]
864    fn roundtrip_noise_u32_tiny() {
865        let channel = ChannelDescription {
866            sample_type: SampleType::U32,
867            name: Default::default(),
868            quantize_linearly: false,
869            sampling: Vec2(1, 1),
870        };
871
872        // Two similar channels.
873        let channels = ChannelList::new(smallvec![channel.clone(), channel]);
874
875        let rectangle = IntegerBounds {
876            position: Vec2(0, 0),
877            size: Vec2(3, 2),
878        };
879
880        let (pixel_bytes, compressed, decompressed) =
881            test_roundtrip_noise_with(channels, rectangle);
882
883        assert_eq!(pixel_bytes.len(), 48);
884        assert_eq!(compressed.len(), 48);
885        assert_eq!(decompressed.len(), 48);
886        assert_eq!(pixel_bytes, decompressed);
887    }
888
889    #[test]
890    fn roundtrip_noise_mix_f32_f16_u32() {
891        let channels = ChannelList::new(smallvec![
892            ChannelDescription {
893                sample_type: SampleType::F32,
894                name: Default::default(),
895                quantize_linearly: false,
896                sampling: Vec2(1, 1),
897            },
898            ChannelDescription {
899                sample_type: SampleType::F16,
900                name: Default::default(),
901                quantize_linearly: false,
902                sampling: Vec2(1, 1),
903            },
904            ChannelDescription {
905                sample_type: SampleType::U32,
906                name: Default::default(),
907                quantize_linearly: false,
908                sampling: Vec2(1, 1),
909            }
910        ]);
911
912        let rectangle = IntegerBounds {
913            position: Vec2(-30, 100),
914            size: Vec2(322, 731),
915        };
916
917        let (pixel_bytes, compressed, decompressed) =
918            test_roundtrip_noise_with(channels, rectangle);
919
920        assert_eq!(pixel_bytes.len(), 2353820);
921        assert_eq!(compressed.len(), 2090578);
922        assert_eq!(decompressed.len(), 2353820);
923    }
924
925    #[test]
926    fn roundtrip_noise_mix_f32_f16_u32_tiny() {
927        let channels = ChannelList::new(smallvec![
928            ChannelDescription {
929                sample_type: SampleType::F32,
930                name: Default::default(),
931                quantize_linearly: false,
932                sampling: Vec2(1, 1),
933            },
934            ChannelDescription {
935                sample_type: SampleType::F16,
936                name: Default::default(),
937                quantize_linearly: false,
938                sampling: Vec2(1, 1),
939            },
940            ChannelDescription {
941                sample_type: SampleType::U32,
942                name: Default::default(),
943                quantize_linearly: false,
944                sampling: Vec2(1, 1),
945            }
946        ]);
947
948        let rectangle = IntegerBounds {
949            position: Vec2(0, 0),
950            size: Vec2(3, 2),
951        };
952
953        let (pixel_bytes, compressed, decompressed) =
954            test_roundtrip_noise_with(channels, rectangle);
955
956        assert_eq!(pixel_bytes.len(), 60);
957        assert_eq!(compressed.len(), 62);
958        assert_eq!(decompressed.len(), 60);
959    }
960
961    #[test]
962    fn border_on_multiview() {
963        // This test is hard to reproduce, so we use the direct image.
964        let path = "tests/images/valid/openexr/MultiView/Adjuster.exr";
965
966        let read_image = read()
967            .no_deep_data()
968            .all_resolution_levels()
969            .all_channels()
970            .all_layers()
971            .all_attributes()
972            .non_parallel();
973
974        let image = read_image.clone().from_file(path).unwrap();
975
976        let mut tmp_bytes = Vec::new();
977        image
978            .write()
979            .non_parallel()
980            .to_buffered(std::io::Cursor::new(&mut tmp_bytes))
981            .unwrap();
982
983        let image2 = read_image
984            .from_buffered(std::io::Cursor::new(tmp_bytes))
985            .unwrap();
986
987        image.assert_equals_result(&image2);
988    }
989}
exr/compression/b44/mod.rs

exr/compression/b44/
mod.rs
