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a64multienc.c
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1 /*
2  * a64 video encoder - multicolor modes
3  * Copyright (c) 2009 Tobias Bindhammer
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 /**
23  * @file
24  * a64 video encoder - multicolor modes
25  */
26 
27 #include "a64colors.h"
28 #include "a64tables.h"
29 #include "elbg.h"
30 #include "internal.h"
31 #include "libavutil/common.h"
32 #include "libavutil/intreadwrite.h"
33 
34 #define DITHERSTEPS 8
35 #define CHARSET_CHARS 256
36 #define INTERLACED 1
37 #define CROP_SCREENS 1
38 
39 #define C64XRES 320
40 #define C64YRES 200
41 
42 typedef struct A64Context {
43  /* general variables */
45 
46  /* variables for multicolor modes */
50  unsigned mc_frame_counter;
52  int *mc_charmap;
53  int *mc_best_cb;
54  int mc_luma_vals[5];
59 
60  /* pts of the next packet that will be output */
61  int64_t next_pts;
62 } A64Context;
63 
64 /* gray gradient */
65 static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
66 
67 /* other possible gradients - to be tested */
68 //static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
69 //static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
70 
71 static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
72 {
73  int blockx, blocky, x, y;
74  int luma = 0;
75  int height = FFMIN(avctx->height, C64YRES);
76  int width = FFMIN(avctx->width , C64XRES);
77  uint8_t *src = p->data[0];
78 
79  for (blocky = 0; blocky < C64YRES; blocky += 8) {
80  for (blockx = 0; blockx < C64XRES; blockx += 8) {
81  for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
82  for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
83  if(x < width && y < height) {
84  /* build average over 2 pixels */
85  luma = (src[(x + 0 + y * p->linesize[0])] +
86  src[(x + 1 + y * p->linesize[0])]) / 2;
87  /* write blocks as linear data now so they are suitable for elbg */
88  dest[0] = luma;
89  }
90  dest++;
91  }
92  }
93  }
94  }
95 }
96 
97 static void render_charset(AVCodecContext *avctx, uint8_t *charset,
98  uint8_t *colrammap)
99 {
100  A64Context *c = avctx->priv_data;
101  uint8_t row1, row2;
102  int charpos, x, y;
103  int a, b;
104  uint8_t pix;
105  int lowdiff, highdiff;
106  int *best_cb = c->mc_best_cb;
107  static uint8_t index1[256];
108  static uint8_t index2[256];
109  static uint8_t dither[256];
110  int i;
111  int distance;
112 
113  /* generate lookup-tables for dither and index before looping */
114  i = 0;
115  for (a=0; a < 256; a++) {
116  if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
117  distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
118  for(b = 0; b <= distance; b++) {
119  dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
120  }
121  i++;
122  }
123  if(i >= c->mc_pal_size - 1) dither[a] = 0;
124  index1[a] = i;
125  index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
126  }
127 
128  /* and render charset */
129  for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
130  lowdiff = 0;
131  highdiff = 0;
132  for (y = 0; y < 8; y++) {
133  row1 = 0; row2 = 0;
134  for (x = 0; x < 4; x++) {
135  pix = best_cb[y * 4 + x];
136 
137  /* accumulate error for brightest/darkest color */
138  if (index1[pix] >= 3)
139  highdiff += pix - c->mc_luma_vals[3];
140  if (index1[pix] < 1)
141  lowdiff += c->mc_luma_vals[1] - pix;
142 
143  row1 <<= 2;
144 
145  if (INTERLACED) {
146  row2 <<= 2;
147  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
148  row1 |= 3-(index2[pix] & 3);
149  else
150  row1 |= 3-(index1[pix] & 3);
151 
152  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
153  row2 |= 3-(index2[pix] & 3);
154  else
155  row2 |= 3-(index1[pix] & 3);
156  }
157  else {
158  if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
159  row1 |= 3-(index2[pix] & 3);
160  else
161  row1 |= 3-(index1[pix] & 3);
162  }
163  }
164  charset[y+0x000] = row1;
165  if (INTERLACED) charset[y+0x800] = row2;
166  }
167  /* do we need to adjust pixels? */
168  if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
169  if (lowdiff > highdiff) {
170  for (x = 0; x < 32; x++)
171  best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
172  } else {
173  for (x = 0; x < 32; x++)
174  best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
175  }
176  charpos--; /* redo now adjusted char */
177  /* no adjustment needed, all fine */
178  } else {
179  /* advance pointers */
180  best_cb += 32;
181  charset += 8;
182 
183  /* remember colorram value */
184  colrammap[charpos] = (highdiff > 0);
185  }
186  }
187 }
188 
190 {
191  A64Context *c = avctx->priv_data;
193  av_free(c->mc_best_cb);
194  av_free(c->mc_charset);
195  av_free(c->mc_charmap);
196  av_free(c->mc_colram);
197  return 0;
198 }
199 
201 {
202  A64Context *c = avctx->priv_data;
203  int a;
204  av_lfg_init(&c->randctx, 1);
205 
206  if (avctx->global_quality < 1) {
207  c->mc_lifetime = 4;
208  } else {
209  c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
210  }
211 
212  av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
213 
214  c->mc_frame_counter = 0;
215  c->mc_use_5col = avctx->codec->id == AV_CODEC_ID_A64_MULTI5;
216  c->mc_pal_size = 4 + c->mc_use_5col;
217 
218  /* precalc luma values for later use */
219  for (a = 0; a < c->mc_pal_size; a++) {
220  c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
221  a64_palette[mc_colors[a]][1] * 0.59 +
222  a64_palette[mc_colors[a]][2] * 0.11;
223  }
224 
225  if (!(c->mc_meta_charset = av_malloc(32000 * c->mc_lifetime * sizeof(int))) ||
226  !(c->mc_best_cb = av_malloc(CHARSET_CHARS * 32 * sizeof(int))) ||
227  !(c->mc_charmap = av_mallocz(1000 * c->mc_lifetime * sizeof(int))) ||
228  !(c->mc_colram = av_mallocz(CHARSET_CHARS * sizeof(uint8_t))) ||
229  !(c->mc_charset = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {
230  av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
231  return AVERROR(ENOMEM);
232  }
233 
234  /* set up extradata */
235  if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {
236  av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
237  return AVERROR(ENOMEM);
238  }
239  avctx->extradata_size = 8 * 4;
240  AV_WB32(avctx->extradata, c->mc_lifetime);
241  AV_WB32(avctx->extradata + 16, INTERLACED);
242 
244  avctx->coded_frame = &c->picture;
246  avctx->coded_frame->key_frame = 1;
247  if (!avctx->codec_tag)
248  avctx->codec_tag = AV_RL32("a64m");
249 
251 
252  return 0;
253 }
254 
255 static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
256 {
257  int a;
258  uint8_t temp;
259  /* only needs to be done in 5col mode */
260  /* XXX could be squeezed to 0x80 bytes */
261  for (a = 0; a < 256; a++) {
262  temp = colram[charmap[a + 0x000]] << 0;
263  temp |= colram[charmap[a + 0x100]] << 1;
264  temp |= colram[charmap[a + 0x200]] << 2;
265  if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
266  buf[a] = temp << 2;
267  }
268 }
269 
271  const AVFrame *pict, int *got_packet)
272 {
273  A64Context *c = avctx->priv_data;
274  AVFrame *const p = &c->picture;
275 
276  int frame;
277  int x, y;
278  int b_height;
279  int b_width;
280 
281  int req_size, ret;
282  uint8_t *buf = NULL;
283 
284  int *charmap = c->mc_charmap;
285  uint8_t *colram = c->mc_colram;
286  uint8_t *charset = c->mc_charset;
287  int *meta = c->mc_meta_charset;
288  int *best_cb = c->mc_best_cb;
289 
290  int charset_size = 0x800 * (INTERLACED + 1);
291  int colram_size = 0x100 * c->mc_use_5col;
292  int screen_size;
293 
294  if(CROP_SCREENS) {
295  b_height = FFMIN(avctx->height,C64YRES) >> 3;
296  b_width = FFMIN(avctx->width ,C64XRES) >> 3;
297  screen_size = b_width * b_height;
298  } else {
299  b_height = C64YRES >> 3;
300  b_width = C64XRES >> 3;
301  screen_size = 0x400;
302  }
303 
304  /* no data, means end encoding asap */
305  if (!pict) {
306  /* all done, end encoding */
307  if (!c->mc_lifetime) return 0;
308  /* no more frames in queue, prepare to flush remaining frames */
309  if (!c->mc_frame_counter) {
310  c->mc_lifetime = 0;
311  }
312  /* still frames in queue so limit lifetime to remaining frames */
313  else c->mc_lifetime = c->mc_frame_counter;
314  /* still new data available */
315  } else {
316  /* fill up mc_meta_charset with data until lifetime exceeds */
317  if (c->mc_frame_counter < c->mc_lifetime) {
318  *p = *pict;
320  p->key_frame = 1;
321  to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
322  c->mc_frame_counter++;
323  if (c->next_pts == AV_NOPTS_VALUE)
324  c->next_pts = pict->pts;
325  /* lifetime is not reached so wait for next frame first */
326  return 0;
327  }
328  }
329 
330  /* lifetime reached so now convert X frames at once */
331  if (c->mc_frame_counter == c->mc_lifetime) {
332  req_size = 0;
333  /* any frames to encode? */
334  if (c->mc_lifetime) {
335  req_size = charset_size + c->mc_lifetime*(screen_size + colram_size);
336  if ((ret = ff_alloc_packet2(avctx, pkt, req_size)) < 0)
337  return ret;
338  buf = pkt->data;
339 
340  /* calc optimal new charset + charmaps */
341  ff_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
342  ff_do_elbg (meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
343 
344  /* create colorram map and a c64 readable charset */
345  render_charset(avctx, charset, colram);
346 
347  /* copy charset to buf */
348  memcpy(buf, charset, charset_size);
349 
350  /* advance pointers */
351  buf += charset_size;
352  charset += charset_size;
353  }
354 
355  /* write x frames to buf */
356  for (frame = 0; frame < c->mc_lifetime; frame++) {
357  /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */
358  for (y = 0; y < b_height; y++) {
359  for (x = 0; x < b_width; x++) {
360  buf[y * b_width + x] = charmap[y * b_width + x];
361  }
362  }
363  /* advance pointers */
364  buf += screen_size;
365  req_size += screen_size;
366 
367  /* compress and copy colram to buf */
368  if (c->mc_use_5col) {
369  a64_compress_colram(buf, charmap, colram);
370  /* advance pointers */
371  buf += colram_size;
372  req_size += colram_size;
373  }
374 
375  /* advance to next charmap */
376  charmap += 1000;
377  }
378 
379  AV_WB32(avctx->extradata + 4, c->mc_frame_counter);
380  AV_WB32(avctx->extradata + 8, charset_size);
381  AV_WB32(avctx->extradata + 12, screen_size + colram_size);
382 
383  /* reset counter */
384  c->mc_frame_counter = 0;
385 
386  pkt->pts = pkt->dts = c->next_pts;
388 
389  pkt->size = req_size;
390  pkt->flags |= AV_PKT_FLAG_KEY;
391  *got_packet = !!req_size;
392  }
393  return 0;
394 }
395 
396 #if CONFIG_A64MULTI_ENCODER
397 AVCodec ff_a64multi_encoder = {
398  .name = "a64multi",
399  .type = AVMEDIA_TYPE_VIDEO,
400  .id = AV_CODEC_ID_A64_MULTI,
401  .priv_data_size = sizeof(A64Context),
403  .encode2 = a64multi_encode_frame,
405  .pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
406  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
407  .capabilities = CODEC_CAP_DELAY,
408 };
409 #endif
410 #if CONFIG_A64MULTI5_ENCODER
411 AVCodec ff_a64multi5_encoder = {
412  .name = "a64multi5",
413  .type = AVMEDIA_TYPE_VIDEO,
415  .priv_data_size = sizeof(A64Context),
417  .encode2 = a64multi_encode_frame,
419  .pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
420  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
421  .capabilities = CODEC_CAP_DELAY,
422 };
423 #endif