FFmpeg coverage

Line	Branch	Exec	Source
1			/*
2			* QuickTime RPZA Video Encoder
3			*
4			* This file is part of FFmpeg.
5			*
6			* FFmpeg is free software; you can redistribute it and/or
7			* modify it under the terms of the GNU Lesser General Public
8			* License as published by the Free Software Foundation; either
9			* version 2.1 of the License, or (at your option) any later version.
10			*
11			* FFmpeg is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14			* Lesser General Public License for more details.
15			*
16			* You should have received a copy of the GNU Lesser General Public
17			* License along with FFmpeg; if not, write to the Free Software
18			* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19			*/
20
21			/**
22			* @file rpzaenc.c
23			* QT RPZA Video Encoder by Todd Kirby <doubleshot@pacbell.net> and David Adler
24			*/
25
26			#include "libavutil/avassert.h"
27			#include "libavutil/common.h"
28			#include "libavutil/opt.h"
29
30			#include "avcodec.h"
31			#include "codec_internal.h"
32			#include "encode.h"
33			#include "put_bits.h"
34
35			typedef struct RpzaContext {
36			AVClass *avclass;
37
38			int skip_frame_thresh;
39			int start_one_color_thresh;
40			int continue_one_color_thresh;
41			int sixteen_color_thresh;
42
43			AVFrame *prev_frame; // buffer for previous source frame
44			PutBitContext pb; // buffer for encoded frame data.
45
46			int frame_width; // width in pixels of source frame
47			int frame_height; // height in pixesl of source frame
48
49			int first_frame; // flag set to one when the first frame is being processed
50			// so that comparisons with previous frame data in not attempted
51			} RpzaContext;
52
53			typedef enum channel_offset {
54			RED = 2,
55			GREEN = 1,
56			BLUE = 0,
57			} channel_offset;
58
59			typedef struct rgb {
60			uint8_t r;
61			uint8_t g;
62			uint8_t b;
63			} rgb;
64
65			#define SQR(x) ((x) * (x))
66
67			/* 15 bit components */
68			#define GET_CHAN(color, chan) (((color) >> ((chan) * 5) & 0x1F) * 8)
69			#define R(color) GET_CHAN(color, RED)
70			#define G(color) GET_CHAN(color, GREEN)
71			#define B(color) GET_CHAN(color, BLUE)
72
73			typedef struct BlockInfo {
74			int row;
75			int col;
76			int block_width;
77			int block_height;
78			int image_width;
79			int image_height;
80			int block_index;
81			uint16_t start;
82			int rowstride;
83			int prev_rowstride;
84			int blocks_per_row;
85			int total_blocks;
86			} BlockInfo;
87
88		✗	static void get_colors(const uint8_t *min, const uint8_t *max, uint8_t color4[4][3])
89			{
90			uint8_t step;
91
92		✗	color4[0][0] = min[0];
93		✗	color4[0][1] = min[1];
94		✗	color4[0][2] = min[2];
95
96		✗	color4[3][0] = max[0];
97		✗	color4[3][1] = max[1];
98		✗	color4[3][2] = max[2];
99
100			// red components
101		✗	step = (color4[3][0] - color4[0][0] + 1) / 3;
102		✗	color4[1][0] = color4[0][0] + step;
103		✗	color4[2][0] = color4[3][0] - step;
104
105			// green components
106		✗	step = (color4[3][1] - color4[0][1] + 1) / 3;
107		✗	color4[1][1] = color4[0][1] + step;
108		✗	color4[2][1] = color4[3][1] - step;
109
110			// blue components
111		✗	step = (color4[3][2] - color4[0][2] + 1) / 3;
112		✗	color4[1][2] = color4[0][2] + step;
113		✗	color4[2][2] = color4[3][2] - step;
114			}
115
116			/* Fill BlockInfo struct with information about a 4x4 block of the image */
117		✗	static int get_block_info(BlockInfo *bi, int block, int prev_frame)
118			{
119		✗	bi->row = block / bi->blocks_per_row;
120		✗	bi->col = block % bi->blocks_per_row;
121
122			// test for right edge block
123		✗	if (bi->col == bi->blocks_per_row - 1 && (bi->image_width % 4) != 0) {
124		✗	bi->block_width = bi->image_width % 4;
125			} else {
126		✗	bi->block_width = 4;
127			}
128
129			// test for bottom edge block
130		✗	if (bi->row == (bi->image_height / 4) && (bi->image_height % 4) != 0) {
131		✗	bi->block_height = bi->image_height % 4;
132			} else {
133		✗	bi->block_height = 4;
134			}
135
136		✗	return block ? (bi->col * 4) + (bi->row * (prev_frame ? bi->prev_rowstride : bi->rowstride) * 4) : 0;
137			}
138
139		✗	static uint16_t rgb24_to_rgb555(const uint8_t *rgb24)
140			{
141		✗	uint16_t rgb555 = 0;
142			uint32_t r, g, b;
143
144		✗	r = rgb24[0] >> 3;
145		✗	g = rgb24[1] >> 3;
146		✗	b = rgb24[2] >> 3;
147
148		✗	rgb555 |= (r << 10);
149		✗	rgb555 |= (g << 5);
150		✗	rgb555 |= (b << 0);
151
152		✗	return rgb555;
153			}
154
155			/*
156			* Returns the total difference between two 24 bit color values
157			*/
158		✗	static int diff_colors(const uint8_t *colorA, const uint8_t *colorB)
159			{
160			int tot;
161
162		✗	tot = SQR(colorA[0] - colorB[0]);
163		✗	tot += SQR(colorA[1] - colorB[1]);
164		✗	tot += SQR(colorA[2] - colorB[2]);
165
166		✗	return tot;
167			}
168
169			/*
170			* Returns the maximum channel difference
171			*/
172		✗	static int max_component_diff(const uint16_t *colorA, const uint16_t *colorB)
173			{
174		✗	int diff, max = 0;
175
176		✗	diff = FFABS(R(colorA[0]) - R(colorB[0]));
177		✗	if (diff > max) {
178		✗	max = diff;
179			}
180		✗	diff = FFABS(G(colorA[0]) - G(colorB[0]));
181		✗	if (diff > max) {
182		✗	max = diff;
183			}
184		✗	diff = FFABS(B(colorA[0]) - B(colorB[0]));
185		✗	if (diff > max) {
186		✗	max = diff;
187			}
188		✗	return max * 8;
189			}
190
191			/*
192			* Find the channel that has the largest difference between minimum and maximum
193			* color values. Put the minimum value in min, maximum in max and the channel
194			* in chan.
195			*/
196		✗	static void get_max_component_diff(const BlockInfo *bi, const uint16_t *block_ptr,
197			uint8_t *min, uint8_t *max, channel_offset *chan)
198			{
199			int x, y;
200			uint8_t min_r, max_r, min_g, max_g, min_b, max_b;
201			uint8_t r, g, b;
202
203			// fix warning about uninitialized vars
204		✗	min_r = min_g = min_b = UINT8_MAX;
205		✗	max_r = max_g = max_b = 0;
206
207			// loop thru and compare pixels
208		✗	for (y = 0; y < bi->block_height; y++) {
209		✗	for (x = 0; x < bi->block_width; x++) {
210			// TODO: optimize
211		✗	min_r = FFMIN(R(block_ptr[x]), min_r);
212		✗	min_g = FFMIN(G(block_ptr[x]), min_g);
213		✗	min_b = FFMIN(B(block_ptr[x]), min_b);
214
215		✗	max_r = FFMAX(R(block_ptr[x]), max_r);
216		✗	max_g = FFMAX(G(block_ptr[x]), max_g);
217		✗	max_b = FFMAX(B(block_ptr[x]), max_b);
218			}
219		✗	block_ptr += bi->rowstride;
220			}
221
222		✗	r = max_r - min_r;
223		✗	g = max_g - min_g;
224		✗	b = max_b - min_b;
225
226		✗	if (r > g && r > b) {
227		✗	*max = max_r;
228		✗	*min = min_r;
229		✗	*chan = RED;
230		✗	} else if (g > b && g >= r) {
231		✗	*max = max_g;
232		✗	*min = min_g;
233		✗	*chan = GREEN;
234			} else {
235		✗	*max = max_b;
236		✗	*min = min_b;
237		✗	*chan = BLUE;
238			}
239			}
240
241			/*
242			* Compare two 4x4 blocks to determine if the total difference between the
243			* blocks is greater than the thresh parameter. Returns -1 if difference
244			* exceeds threshold or zero otherwise.
245			*/
246		✗	static int compare_blocks(const uint16_t *block1, const uint16_t *block2,
247			const BlockInfo *bi, int thresh)
248			{
249		✗	int x, y, diff = 0;
250		✗	for (y = 0; y < bi->block_height; y++) {
251		✗	for (x = 0; x < bi->block_width; x++) {
252		✗	diff = max_component_diff(&block1[x], &block2[x]);
253		✗	if (diff >= thresh) {
254		✗	return -1;
255			}
256			}
257		✗	block1 += bi->prev_rowstride;
258		✗	block2 += bi->rowstride;
259			}
260		✗	return 0;
261			}
262
263			/*
264			* Determine the fit of one channel to another within a 4x4 block. This
265			* is used to determine the best palette choices for 4-color encoding.
266			*/
267		✗	static int leastsquares(const uint16_t *block_ptr, const BlockInfo *bi,
268			channel_offset xchannel, channel_offset ychannel,
269			double *slope, double *y_intercept, double *correlation_coef)
270			{
271		✗	double sumx = 0, sumy = 0, sumx2 = 0, sumy2 = 0, sumxy = 0,
272		✗	sumx_sq = 0, sumy_sq = 0, tmp, tmp2;
273			int i, j, count;
274			uint8_t x, y;
275
276		✗	count = bi->block_height * bi->block_width;
277
278		✗	if (count < 2)
279		✗	return -1;
280
281		✗	for (i = 0; i < bi->block_height; i++) {
282		✗	for (j = 0; j < bi->block_width; j++) {
283		✗	x = GET_CHAN(block_ptr[j], xchannel);
284		✗	y = GET_CHAN(block_ptr[j], ychannel);
285		✗	sumx += x;
286		✗	sumy += y;
287		✗	sumx2 += x * x;
288		✗	sumy2 += y * y;
289		✗	sumxy += x * y;
290			}
291		✗	block_ptr += bi->rowstride;
292			}
293
294		✗	sumx_sq = sumx * sumx;
295		✗	tmp = (count * sumx2 - sumx_sq);
296
297			// guard against div/0
298		✗	if (tmp == 0)
299		✗	return -2;
300
301		✗	sumy_sq = sumy * sumy;
302
303		✗	*slope = (sumx * sumy - sumxy) / tmp;
304		✗	*y_intercept = (sumy - (*slope) * sumx) / count;
305
306		✗	tmp2 = count * sumy2 - sumy_sq;
307		✗	if (tmp2 == 0) {
308		✗	*correlation_coef = 0.0;
309			} else {
310		✗	*correlation_coef = (count * sumxy - sumx * sumy) /
311		✗	sqrt(tmp * tmp2);
312			}
313
314		✗	return 0; // success
315			}
316
317			/*
318			* Determine the amount of error in the leastsquares fit.
319			*/
320		✗	static int calc_lsq_max_fit_error(const uint16_t *block_ptr, const BlockInfo *bi,
321			int min, int max, int tmp_min, int tmp_max,
322			channel_offset xchannel, channel_offset ychannel)
323			{
324			int i, j, x, y;
325			int err;
326		✗	int max_err = 0;
327
328		✗	for (i = 0; i < bi->block_height; i++) {
329		✗	for (j = 0; j < bi->block_width; j++) {
330			int x_inc, lin_y, lin_x;
331		✗	x = GET_CHAN(block_ptr[j], xchannel);
332		✗	y = GET_CHAN(block_ptr[j], ychannel);
333
334			/* calculate x_inc as the 4-color index (0..3) */
335		✗	x_inc = floor( (x - min) * 3.0 / (max - min) + 0.5);
336		✗	x_inc = FFMAX(FFMIN(3, x_inc), 0);
337
338			/* calculate lin_y corresponding to x_inc */
339		✗	lin_y = (int)(tmp_min + (tmp_max - tmp_min) * x_inc / 3.0 + 0.5);
340
341		✗	err = FFABS(lin_y - y);
342		✗	if (err > max_err)
343		✗	max_err = err;
344
345			/* calculate lin_x corresponding to x_inc */
346		✗	lin_x = (int)(min + (max - min) * x_inc / 3.0 + 0.5);
347
348		✗	err = FFABS(lin_x - x);
349		✗	if (err > max_err)
350		✗	max_err += err;
351			}
352		✗	block_ptr += bi->rowstride;
353			}
354
355		✗	return max_err;
356			}
357
358			/*
359			* Find the closest match to a color within the 4-color palette
360			*/
361		✗	static int match_color(const uint16_t *color, uint8_t colors[4][3])
362			{
363		✗	int ret = 0;
364		✗	int smallest_variance = INT_MAX;
365			uint8_t dithered_color[3];
366
367		✗	for (int channel = 0; channel < 3; channel++) {
368		✗	dithered_color[channel] = GET_CHAN(color[0], channel);
369			}
370
371		✗	for (int palette_entry = 0; palette_entry < 4; palette_entry++) {
372		✗	int variance = diff_colors(dithered_color, colors[palette_entry]);
373
374		✗	if (variance < smallest_variance) {
375		✗	smallest_variance = variance;
376		✗	ret = palette_entry;
377			}
378			}
379
380		✗	return ret;
381			}
382
383			/*
384			* Encode a block using the 4-color opcode and palette. return number of
385			* blocks encoded (until we implement multi-block 4 color runs this will
386			* always be 1)
387			*/
388		✗	static int encode_four_color_block(const uint8_t *min_color, const uint8_t *max_color,
389			PutBitContext *pb, const uint16_t *block_ptr, const BlockInfo *bi)
390			{
391		✗	const int y_size = FFMIN(4, bi->image_height - bi->row * 4);
392		✗	const int x_size = FFMIN(4, bi->image_width - bi->col * 4);
393			uint8_t color4[4][3];
394			uint16_t rounded_max, rounded_min;
395			int idx;
396
397			// round min and max wider
398		✗	rounded_min = rgb24_to_rgb555(min_color);
399		✗	rounded_max = rgb24_to_rgb555(max_color);
400
401			// put a and b colors
402			// encode 4 colors = first 16 bit color with MSB zeroed and...
403		✗	put_bits(pb, 16, rounded_max & ~0x8000);
404			// ...second 16 bit color with MSB on.
405		✗	put_bits(pb, 16, rounded_min | 0x8000);
406
407		✗	get_colors(min_color, max_color, color4);
408
409		✗	for (int y = 0; y < y_size; y++) {
410		✗	for (int x = 0; x < x_size; x++) {
411		✗	idx = match_color(&block_ptr[x], color4);
412		✗	put_bits(pb, 2, idx);
413			}
414
415		✗	for (int x = x_size; x < 4; x++)
416		✗	put_bits(pb, 2, idx);
417		✗	block_ptr += bi->rowstride;
418			}
419
420		✗	for (int y = y_size; y < 4; y++) {
421		✗	for (int x = 0; x < 4; x++)
422		✗	put_bits(pb, 2, 0);
423			}
424		✗	return 1; // num blocks encoded
425			}
426
427			/*
428			* Copy a 4x4 block from the current frame buffer to the previous frame buffer.
429			*/
430		✗	static void update_block_in_prev_frame(const uint16_t *src_pixels,
431			uint16_t *dest_pixels,
432			const BlockInfo *bi, int block_counter)
433			{
434		✗	const int y_size = FFMIN(4, bi->image_height - bi->row * 4);
435		✗	const int x_size = FFMIN(4, bi->image_width - bi->col * 4) * 2;
436
437		✗	for (int y = 0; y < y_size; y++) {
438		✗	memcpy(dest_pixels, src_pixels, x_size);
439		✗	dest_pixels += bi->prev_rowstride;
440		✗	src_pixels += bi->rowstride;
441			}
442			}
443
444			/*
445			* update statistics for the specified block. If first_block,
446			* it initializes the statistics. Otherwise it updates the statistics IF THIS
447			* BLOCK IS SUITABLE TO CONTINUE A 1-COLOR RUN. That is, it checks whether
448			* the range of colors (since the routine was called first_block != 0) are
449			* all close enough intensities to be represented by a single color.
450
451			* The routine returns 0 if this block is too different to be part of
452			* the same run of 1-color blocks. The routine returns 1 if this
453			* block can be part of the same 1-color block run.
454
455			* If the routine returns 1, it also updates its arguments to include
456			* the statistics of this block. Otherwise, the stats are unchanged
457			* and don't include the current block.
458			*/
459		✗	static int update_block_stats(RpzaContext *s, const BlockInfo *bi, const uint16_t *block,
460			uint8_t min_color[3], uint8_t max_color[3],
461			int *total_rgb, int *total_pixels,
462			uint8_t avg_color[3], int first_block)
463			{
464			int x, y;
465			int is_in_range;
466			int total_pixels_blk;
467			int threshold;
468
469			uint8_t min_color_blk[3], max_color_blk[3];
470			int total_rgb_blk[3];
471			uint8_t avg_color_blk[3];
472
473		✗	if (first_block) {
474		✗	min_color[0] = UINT8_MAX;
475		✗	min_color[1] = UINT8_MAX;
476		✗	min_color[2] = UINT8_MAX;
477		✗	max_color[0] = 0;
478		✗	max_color[1] = 0;
479		✗	max_color[2] = 0;
480		✗	total_rgb[0] = 0;
481		✗	total_rgb[1] = 0;
482		✗	total_rgb[2] = 0;
483		✗	*total_pixels = 0;
484		✗	threshold = s->start_one_color_thresh;
485			} else {
486		✗	threshold = s->continue_one_color_thresh;
487			}
488
489			/*
490			The *_blk variables will include the current block.
491			Initialize them based on the blocks so far.
492			*/
493		✗	min_color_blk[0] = min_color[0];
494		✗	min_color_blk[1] = min_color[1];
495		✗	min_color_blk[2] = min_color[2];
496		✗	max_color_blk[0] = max_color[0];
497		✗	max_color_blk[1] = max_color[1];
498		✗	max_color_blk[2] = max_color[2];
499		✗	total_rgb_blk[0] = total_rgb[0];
500		✗	total_rgb_blk[1] = total_rgb[1];
501		✗	total_rgb_blk[2] = total_rgb[2];
502		✗	total_pixels_blk = *total_pixels + bi->block_height * bi->block_width;
503
504			/*
505			Update stats for this block's pixels
506			*/
507		✗	for (y = 0; y < bi->block_height; y++) {
508		✗	for (x = 0; x < bi->block_width; x++) {
509		✗	total_rgb_blk[0] += R(block[x]);
510		✗	total_rgb_blk[1] += G(block[x]);
511		✗	total_rgb_blk[2] += B(block[x]);
512
513		✗	min_color_blk[0] = FFMIN(R(block[x]), min_color_blk[0]);
514		✗	min_color_blk[1] = FFMIN(G(block[x]), min_color_blk[1]);
515		✗	min_color_blk[2] = FFMIN(B(block[x]), min_color_blk[2]);
516
517		✗	max_color_blk[0] = FFMAX(R(block[x]), max_color_blk[0]);
518		✗	max_color_blk[1] = FFMAX(G(block[x]), max_color_blk[1]);
519		✗	max_color_blk[2] = FFMAX(B(block[x]), max_color_blk[2]);
520			}
521		✗	block += bi->rowstride;
522			}
523
524			/*
525			Calculate average color including current block.
526			*/
527		✗	avg_color_blk[0] = total_rgb_blk[0] / total_pixels_blk;
528		✗	avg_color_blk[1] = total_rgb_blk[1] / total_pixels_blk;
529		✗	avg_color_blk[2] = total_rgb_blk[2] / total_pixels_blk;
530
531			/*
532			Are all the pixels within threshold of the average color?
533			*/
534		✗	is_in_range = (max_color_blk[0] - avg_color_blk[0] <= threshold &&
535		✗	max_color_blk[1] - avg_color_blk[1] <= threshold &&
536		✗	max_color_blk[2] - avg_color_blk[2] <= threshold &&
537		✗	avg_color_blk[0] - min_color_blk[0] <= threshold &&
538		✗	avg_color_blk[1] - min_color_blk[1] <= threshold &&
539		✗	avg_color_blk[2] - min_color_blk[2] <= threshold);
540
541		✗	if (is_in_range) {
542			/*
543			Set the output variables to include this block.
544			*/
545		✗	min_color[0] = min_color_blk[0];
546		✗	min_color[1] = min_color_blk[1];
547		✗	min_color[2] = min_color_blk[2];
548		✗	max_color[0] = max_color_blk[0];
549		✗	max_color[1] = max_color_blk[1];
550		✗	max_color[2] = max_color_blk[2];
551		✗	total_rgb[0] = total_rgb_blk[0];
552		✗	total_rgb[1] = total_rgb_blk[1];
553		✗	total_rgb[2] = total_rgb_blk[2];
554		✗	*total_pixels = total_pixels_blk;
555		✗	avg_color[0] = avg_color_blk[0];
556		✗	avg_color[1] = avg_color_blk[1];
557		✗	avg_color[2] = avg_color_blk[2];
558			}
559
560		✗	return is_in_range;
561			}
562
563		✗	static void rpza_encode_stream(RpzaContext *s, const AVFrame *pict)
564			{
565			BlockInfo bi;
566		✗	int block_counter = 0;
567			int n_blocks;
568			int total_blocks;
569			int prev_block_offset;
570		✗	int block_offset = 0;
571		✗	int pblock_offset = 0;
572		✗	uint8_t min = 0, max = 0;
573			channel_offset chan;
574			int i;
575			int tmp_min, tmp_max;
576			int total_rgb[3];
577			uint8_t avg_color[3];
578			int pixel_count;
579			uint8_t min_color[3], max_color[3];
580			double slope, y_intercept, correlation_coef;
581		✗	const uint16_t *src_pixels = (const uint16_t *)pict->data[0];
582		✗	uint16_t *prev_pixels = (uint16_t *)s->prev_frame->data[0];
583
584			/* Number of 4x4 blocks in frame. */
585		✗	total_blocks = ((s->frame_width + 3) / 4) * ((s->frame_height + 3) / 4);
586
587		✗	bi.image_width = s->frame_width;
588		✗	bi.image_height = s->frame_height;
589		✗	bi.rowstride = pict->linesize[0] / 2;
590		✗	bi.prev_rowstride = s->prev_frame->linesize[0] / 2;
591
592		✗	bi.blocks_per_row = (s->frame_width + 3) / 4;
593
594		✗	while (block_counter < total_blocks) {
595			// SKIP CHECK
596			// make sure we have a valid previous frame and we're not writing
597			// a key frame
598		✗	if (!s->first_frame) {
599		✗	n_blocks = 0;
600		✗	prev_block_offset = 0;
601
602		✗	while (n_blocks < 32 && block_counter + n_blocks < total_blocks) {
603		✗	block_offset = get_block_info(&bi, block_counter + n_blocks, 0);
604		✗	pblock_offset = get_block_info(&bi, block_counter + n_blocks, 1);
605
606			// multi-block opcodes cannot span multiple rows.
607			// If we're starting a new row, break out and write the opcode
608			/* TODO: Should eventually use bi.row here to determine when a
609			row break occurs, but that is currently breaking the
610			quicktime player. This is probably due to a bug in the
611			way I'm calculating the current row.
612			*/
613		✗	if (prev_block_offset && block_offset - prev_block_offset > 12) {
614		✗	break;
615			}
616
617		✗	prev_block_offset = block_offset;
618
619		✗	if (compare_blocks(&prev_pixels[pblock_offset],
620		✗	&src_pixels[block_offset], &bi, s->skip_frame_thresh) != 0) {
621			// write out skipable blocks
622		✗	if (n_blocks) {
623
624			// write skip opcode
625		✗	put_bits(&s->pb, 8, 0x80 | (n_blocks - 1));
626		✗	block_counter += n_blocks;
627
628		✗	goto post_skip;
629			}
630		✗	break;
631			}
632
633			/*
634			* NOTE: we don't update skipped blocks in the previous frame buffer
635			* since skipped needs always to be compared against the first skipped
636			* block to avoid artifacts during gradual fade in/outs.
637			*/
638
639			// update_block_in_prev_frame(&src_pixels[block_offset],
640			// &prev_pixels[pblock_offset], &bi, block_counter + n_blocks);
641
642		✗	n_blocks++;
643			}
644
645			// we're either at the end of the frame or we've reached the maximum
646			// of 32 blocks in a run. Write out the run.
647		✗	if (n_blocks) {
648			// write skip opcode
649		✗	put_bits(&s->pb, 8, 0x80 | (n_blocks - 1));
650		✗	block_counter += n_blocks;
651
652		✗	continue;
653			}
654
655			} else {
656		✗	block_offset = get_block_info(&bi, block_counter, 0);
657		✗	pblock_offset = get_block_info(&bi, block_counter, 1);
658			}
659		✗	post_skip :
660
661			// ONE COLOR CHECK
662		✗	if (update_block_stats(s, &bi, &src_pixels[block_offset],
663			min_color, max_color,
664			total_rgb, &pixel_count, avg_color, 1)) {
665		✗	prev_block_offset = block_offset;
666
667		✗	n_blocks = 1;
668
669			/* update this block in the previous frame buffer */
670		✗	update_block_in_prev_frame(&src_pixels[block_offset],
671		✗	&prev_pixels[pblock_offset], &bi, block_counter + n_blocks);
672
673			// check for subsequent blocks with the same color
674		✗	while (n_blocks < 32 && block_counter + n_blocks < total_blocks) {
675		✗	block_offset = get_block_info(&bi, block_counter + n_blocks, 0);
676		✗	pblock_offset = get_block_info(&bi, block_counter + n_blocks, 1);
677
678			// multi-block opcodes cannot span multiple rows.
679			// If we've hit end of a row, break out and write the opcode
680		✗	if (block_offset - prev_block_offset > 12) {
681		✗	break;
682			}
683
684		✗	if (!update_block_stats(s, &bi, &src_pixels[block_offset],
685			min_color, max_color,
686			total_rgb, &pixel_count, avg_color, 0)) {
687		✗	break;
688			}
689
690		✗	prev_block_offset = block_offset;
691
692			/* update this block in the previous frame buffer */
693		✗	update_block_in_prev_frame(&src_pixels[block_offset],
694		✗	&prev_pixels[pblock_offset], &bi, block_counter + n_blocks);
695
696		✗	n_blocks++;
697			}
698
699			// write one color opcode.
700		✗	put_bits(&s->pb, 8, 0xa0 | (n_blocks - 1));
701			// write color to encode.
702		✗	put_bits(&s->pb, 16, rgb24_to_rgb555(avg_color));
703			// skip past the blocks we've just encoded.
704		✗	block_counter += n_blocks;
705			} else { // FOUR COLOR CHECK
706		✗	int err = 0;
707
708			// get max component diff for block
709		✗	get_max_component_diff(&bi, &src_pixels[block_offset], &min, &max, &chan);
710
711		✗	min_color[0] = 0;
712		✗	max_color[0] = 0;
713		✗	min_color[1] = 0;
714		✗	max_color[1] = 0;
715		✗	min_color[2] = 0;
716		✗	max_color[2] = 0;
717
718			// run least squares against other two components
719		✗	for (i = 0; i < 3; i++) {
720		✗	if (i == chan) {
721		✗	min_color[i] = min;
722		✗	max_color[i] = max;
723		✗	continue;
724			}
725
726		✗	slope = y_intercept = correlation_coef = 0;
727
728		✗	if (leastsquares(&src_pixels[block_offset], &bi, chan, i,
729			&slope, &y_intercept, &correlation_coef)) {
730		✗	min_color[i] = GET_CHAN(src_pixels[block_offset], i);
731		✗	max_color[i] = GET_CHAN(src_pixels[block_offset], i);
732			} else {
733		✗	tmp_min = (int)(0.5 + min * slope + y_intercept);
734		✗	tmp_max = (int)(0.5 + max * slope + y_intercept);
735
736		✗	av_assert0(tmp_min <= tmp_max);
737			// clamp min and max color values
738		✗	tmp_min = av_clip_uint8(tmp_min);
739		✗	tmp_max = av_clip_uint8(tmp_max);
740
741		✗	err = FFMAX(calc_lsq_max_fit_error(&src_pixels[block_offset], &bi,
742			min, max, tmp_min, tmp_max, chan, i), err);
743
744		✗	min_color[i] = tmp_min;
745		✗	max_color[i] = tmp_max;
746			}
747			}
748
749		✗	if (err > s->sixteen_color_thresh) { // DO SIXTEEN COLOR BLOCK
750			const uint16_t *row_ptr;
751			int y_size, rgb555;
752
753		✗	block_offset = get_block_info(&bi, block_counter, 0);
754		✗	pblock_offset = get_block_info(&bi, block_counter, 1);
755
756		✗	row_ptr = &src_pixels[block_offset];
757		✗	y_size = FFMIN(4, bi.image_height - bi.row * 4);
758
759		✗	for (int y = 0; y < y_size; y++) {
760		✗	for (int x = 0; x < 4; x++) {
761		✗	rgb555 = row_ptr[x] & ~0x8000;
762
763		✗	put_bits(&s->pb, 16, rgb555);
764			}
765		✗	row_ptr += bi.rowstride;
766			}
767
768		✗	for (int y = y_size; y < 4; y++) {
769		✗	for (int x = 0; x < 4; x++)
770		✗	put_bits(&s->pb, 16, 0);
771			}
772
773		✗	block_counter++;
774			} else { // FOUR COLOR BLOCK
775		✗	block_counter += encode_four_color_block(min_color, max_color,
776		✗	&s->pb, &src_pixels[block_offset], &bi);
777			}
778
779			/* update this block in the previous frame buffer */
780		✗	update_block_in_prev_frame(&src_pixels[block_offset],
781		✗	&prev_pixels[pblock_offset], &bi, block_counter);
782			}
783			}
784			}
785
786		✗	static int rpza_encode_init(AVCodecContext *avctx)
787			{
788		✗	RpzaContext *s = avctx->priv_data;
789
790		✗	s->frame_width = avctx->width;
791		✗	s->frame_height = avctx->height;
792
793		✗	s->prev_frame = av_frame_alloc();
794		✗	if (!s->prev_frame)
795		✗	return AVERROR(ENOMEM);
796
797		✗	return 0;
798			}
799
800		✗	static int rpza_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
801			const AVFrame *pict, int *got_packet)
802			{
803		✗	RpzaContext *s = avctx->priv_data;
804			uint8_t *buf;
805		✗	int ret = ff_alloc_packet(avctx, pkt, 4LL + 6LL * avctx->height * avctx->width);
806
807		✗	if (ret < 0)
808		✗	return ret;
809
810		✗	init_put_bits(&s->pb, pkt->data, pkt->size);
811
812			// skip 4 byte header, write it later once the size of the chunk is known
813		✗	put_bits32(&s->pb, 0x00);
814
815		✗	if (!s->prev_frame->data[0]) {
816		✗	s->first_frame = 1;
817		✗	s->prev_frame->format = pict->format;
818		✗	s->prev_frame->width = pict->width;
819		✗	s->prev_frame->height = pict->height;
820		✗	ret = av_frame_get_buffer(s->prev_frame, 0);
821		✗	if (ret < 0)
822		✗	return ret;
823			} else {
824		✗	s->first_frame = 0;
825			}
826
827		✗	rpza_encode_stream(s, pict);
828
829		✗	flush_put_bits(&s->pb);
830
831		✗	av_shrink_packet(pkt, put_bytes_output(&s->pb));
832		✗	buf = pkt->data;
833
834			// write header opcode
835		✗	buf[0] = 0xe1; // chunk opcode
836
837			// write chunk length
838		✗	AV_WB24(buf + 1, pkt->size);
839
840		✗	*got_packet = 1;
841
842		✗	return 0;
843			}
844
845		✗	static int rpza_encode_end(AVCodecContext *avctx)
846			{
847		✗	RpzaContext *s = (RpzaContext *)avctx->priv_data;
848
849		✗	av_frame_free(&s->prev_frame);
850
851		✗	return 0;
852			}
853
854			#define OFFSET(x) offsetof(RpzaContext, x)
855			#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
856			static const AVOption options[] = {
857			{ "skip_frame_thresh", NULL, OFFSET(skip_frame_thresh), AV_OPT_TYPE_INT, {.i64=1}, 0, 24, VE},
858			{ "start_one_color_thresh", NULL, OFFSET(start_one_color_thresh), AV_OPT_TYPE_INT, {.i64=1}, 0, 24, VE},
859			{ "continue_one_color_thresh", NULL, OFFSET(continue_one_color_thresh), AV_OPT_TYPE_INT, {.i64=0}, 0, 24, VE},
860			{ "sixteen_color_thresh", NULL, OFFSET(sixteen_color_thresh), AV_OPT_TYPE_INT, {.i64=1}, 0, 24, VE},
861			{ NULL },
862			};
863
864			static const AVClass rpza_class = {
865			.class_name = "rpza",
866			.item_name = av_default_item_name,
867			.option = options,
868			.version = LIBAVUTIL_VERSION_INT,
869			};
870
871			const FFCodec ff_rpza_encoder = {
872			.p.name = "rpza",
873			CODEC_LONG_NAME("QuickTime video (RPZA)"),
874			.p.type = AVMEDIA_TYPE_VIDEO,
875			.p.id = AV_CODEC_ID_RPZA,
876			.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE,
877			.priv_data_size = sizeof(RpzaContext),
878			.p.priv_class = &rpza_class,
879			.init = rpza_encode_init,
880			FF_CODEC_ENCODE_CB(rpza_encode_frame),
881			.close = rpza_encode_end,
882			.p.pix_fmts = (const enum AVPixelFormat[]) { AV_PIX_FMT_RGB555,
883			AV_PIX_FMT_NONE},
884			};
885