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 Libav.
6  *
7  * Libav 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  * Libav 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 Libav; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
27 #include "a64enc.h"
28 #include "a64colors.h"
29 #include "a64tables.h"
30 #include "elbg.h"
31 #include "libavutil/intreadwrite.h"
32 
33 #define DITHERSTEPS 8
34 #define CHARSET_CHARS 256
35 #define INTERLACED 1
36 #define CROP_SCREENS 1
37 
38 /* gray gradient */
39 static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
40 
41 /* other possible gradients - to be tested */
42 //static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
43 //static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
44 
45 static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
46 {
47  int blockx, blocky, x, y;
48  int luma = 0;
49  int height = FFMIN(avctx->height, C64YRES);
50  int width = FFMIN(avctx->width , C64XRES);
51  uint8_t *src = p->data[0];
52 
53  for (blocky = 0; blocky < C64YRES; blocky += 8) {
54  for (blockx = 0; blockx < C64XRES; blockx += 8) {
55  for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
56  for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
57  if(x < width && y < height) {
58  /* build average over 2 pixels */
59  luma = (src[(x + 0 + y * p->linesize[0])] +
60  src[(x + 1 + y * p->linesize[0])]) / 2;
61  /* write blocks as linear data now so they are suitable for elbg */
62  dest[0] = luma;
63  }
64  dest++;
65  }
66  }
67  }
68  }
69 }
70 
71 static void render_charset(AVCodecContext *avctx, uint8_t *charset,
72  uint8_t *colrammap)
73 {
74  A64Context *c = avctx->priv_data;
75  uint8_t row1, row2;
76  int charpos, x, y;
77  int a, b;
78  uint8_t pix;
79  int lowdiff, highdiff;
80  int *best_cb = c->mc_best_cb;
81  static uint8_t index1[256];
82  static uint8_t index2[256];
83  static uint8_t dither[256];
84  int i;
85  int distance;
86 
87  /* generate lookup-tables for dither and index before looping */
88  i = 0;
89  for (a=0; a < 256; a++) {
90  if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
91  distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
92  for(b = 0; b <= distance; b++) {
93  dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
94  }
95  i++;
96  }
97  if(i >= c->mc_pal_size - 1) dither[a] = 0;
98  index1[a] = i;
99  index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
100  }
101 
102  /* and render charset */
103  for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
104  lowdiff = 0;
105  highdiff = 0;
106  for (y = 0; y < 8; y++) {
107  row1 = 0; row2 = 0;
108  for (x = 0; x < 4; x++) {
109  pix = best_cb[y * 4 + x];
110 
111  /* accumulate error for brightest/darkest color */
112  if (index1[pix] >= 3)
113  highdiff += pix - c->mc_luma_vals[3];
114  if (index1[pix] < 1)
115  lowdiff += c->mc_luma_vals[1] - pix;
116 
117  row1 <<= 2;
118 
119  if (INTERLACED) {
120  row2 <<= 2;
121  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
122  row1 |= 3-(index2[pix] & 3);
123  else
124  row1 |= 3-(index1[pix] & 3);
125 
126  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
127  row2 |= 3-(index2[pix] & 3);
128  else
129  row2 |= 3-(index1[pix] & 3);
130  }
131  else {
132  if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
133  row1 |= 3-(index2[pix] & 3);
134  else
135  row1 |= 3-(index1[pix] & 3);
136  }
137  }
138  charset[y+0x000] = row1;
139  if (INTERLACED) charset[y+0x800] = row2;
140  }
141  /* do we need to adjust pixels? */
142  if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
143  if (lowdiff > highdiff) {
144  for (x = 0; x < 32; x++)
145  best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
146  } else {
147  for (x = 0; x < 32; x++)
148  best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
149  }
150  charpos--; /* redo now adjusted char */
151  /* no adjustment needed, all fine */
152  } else {
153  /* advance pointers */
154  best_cb += 32;
155  charset += 8;
156 
157  /* remember colorram value */
158  colrammap[charpos] = (highdiff > 0);
159  }
160  }
161 }
162 
164 {
165  A64Context *c = avctx->priv_data;
167  av_free(c->mc_best_cb);
168  av_free(c->mc_charset);
169  av_free(c->mc_charmap);
170  av_free(c->mc_colram);
171  return 0;
172 }
173 
175 {
176  A64Context *c = avctx->priv_data;
177  int a;
178  av_lfg_init(&c->randctx, 1);
179 
180  if (avctx->global_quality < 1) {
181  c->mc_lifetime = 4;
182  } else {
183  c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
184  }
185 
186  av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
187 
188  c->mc_frame_counter = 0;
189  c->mc_use_5col = avctx->codec->id == CODEC_ID_A64_MULTI5;
190  c->mc_pal_size = 4 + c->mc_use_5col;
191 
192  /* precalc luma values for later use */
193  for (a = 0; a < c->mc_pal_size; a++) {
194  c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
195  a64_palette[mc_colors[a]][1] * 0.59 +
196  a64_palette[mc_colors[a]][2] * 0.11;
197  }
198 
199  if (!(c->mc_meta_charset = av_malloc(32000 * c->mc_lifetime * sizeof(int))) ||
200  !(c->mc_best_cb = av_malloc(CHARSET_CHARS * 32 * sizeof(int))) ||
201  !(c->mc_charmap = av_mallocz(1000 * c->mc_lifetime * sizeof(int))) ||
202  !(c->mc_colram = av_mallocz(CHARSET_CHARS * sizeof(uint8_t))) ||
203  !(c->mc_charset = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {
204  av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
205  return AVERROR(ENOMEM);
206  }
207 
208  /* set up extradata */
209  if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {
210  av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
211  return AVERROR(ENOMEM);
212  }
213  avctx->extradata_size = 8 * 4;
214  AV_WB32(avctx->extradata, c->mc_lifetime);
215  AV_WB32(avctx->extradata + 16, INTERLACED);
216 
218  avctx->coded_frame = &c->picture;
220  avctx->coded_frame->key_frame = 1;
221  if (!avctx->codec_tag)
222  avctx->codec_tag = AV_RL32("a64m");
223 
224  return 0;
225 }
226 
227 static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
228 {
229  int a;
230  uint8_t temp;
231  /* only needs to be done in 5col mode */
232  /* XXX could be squeezed to 0x80 bytes */
233  for (a = 0; a < 256; a++) {
234  temp = colram[charmap[a + 0x000]] << 0;
235  temp |= colram[charmap[a + 0x100]] << 1;
236  temp |= colram[charmap[a + 0x200]] << 2;
237  if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
238  buf[a] = temp << 2;
239  }
240 }
241 
242 static int a64multi_encode_frame(AVCodecContext *avctx, unsigned char *buf,
243  int buf_size, void *data)
244 {
245  A64Context *c = avctx->priv_data;
246  AVFrame *pict = data;
247  AVFrame *const p = (AVFrame *) & c->picture;
248 
249  int frame;
250  int x, y;
251  int b_height;
252  int b_width;
253 
254  int req_size;
255 
256  int *charmap = c->mc_charmap;
257  uint8_t *colram = c->mc_colram;
258  uint8_t *charset = c->mc_charset;
259  int *meta = c->mc_meta_charset;
260  int *best_cb = c->mc_best_cb;
261 
262  int charset_size = 0x800 * (INTERLACED + 1);
263  int colram_size = 0x100 * c->mc_use_5col;
264  int screen_size;
265 
266  if(CROP_SCREENS) {
267  b_height = FFMIN(avctx->height,C64YRES) >> 3;
268  b_width = FFMIN(avctx->width ,C64XRES) >> 3;
269  screen_size = b_width * b_height;
270  } else {
271  b_height = C64YRES >> 3;
272  b_width = C64XRES >> 3;
273  screen_size = 0x400;
274  }
275 
276  /* no data, means end encoding asap */
277  if (!data) {
278  /* all done, end encoding */
279  if (!c->mc_lifetime) return 0;
280  /* no more frames in queue, prepare to flush remaining frames */
281  if (!c->mc_frame_counter) {
282  c->mc_lifetime = 0;
283  }
284  /* still frames in queue so limit lifetime to remaining frames */
285  else c->mc_lifetime = c->mc_frame_counter;
286  /* still new data available */
287  } else {
288  /* fill up mc_meta_charset with data until lifetime exceeds */
289  if (c->mc_frame_counter < c->mc_lifetime) {
290  *p = *pict;
292  p->key_frame = 1;
293  to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
294  c->mc_frame_counter++;
295  /* lifetime is not reached so wait for next frame first */
296  return 0;
297  }
298  }
299 
300  /* lifetime reached so now convert X frames at once */
301  if (c->mc_frame_counter == c->mc_lifetime) {
302  req_size = 0;
303  /* any frames to encode? */
304  if (c->mc_lifetime) {
305  /* calc optimal new charset + charmaps */
306  ff_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
307  ff_do_elbg (meta, 32, 1000 * c->mc_lifetime, best_cb, CHARSET_CHARS, 50, charmap, &c->randctx);
308 
309  /* create colorram map and a c64 readable charset */
310  render_charset(avctx, charset, colram);
311 
312  /* copy charset to buf */
313  memcpy(buf,charset, charset_size);
314 
315  /* advance pointers */
316  buf += charset_size;
317  charset += charset_size;
318  req_size += charset_size;
319  }
320  /* no charset so clean buf */
321  else memset(buf, 0, charset_size);
322 
323  /* write x frames to buf */
324  for (frame = 0; frame < c->mc_lifetime; frame++) {
325  /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */
326  for (y = 0; y < b_height; y++) {
327  for (x = 0; x < b_width; x++) {
328  buf[y * b_width + x] = charmap[y * b_width + x];
329  }
330  }
331  /* advance pointers */
332  buf += screen_size;
333  req_size += screen_size;
334 
335  /* compress and copy colram to buf */
336  if (c->mc_use_5col) {
337  a64_compress_colram(buf, charmap, colram);
338  /* advance pointers */
339  buf += colram_size;
340  req_size += colram_size;
341  }
342 
343  /* advance to next charmap */
344  charmap += 1000;
345  }
346 
347  AV_WB32(avctx->extradata + 4, c->mc_frame_counter);
348  AV_WB32(avctx->extradata + 8, charset_size);
349  AV_WB32(avctx->extradata + 12, screen_size + colram_size);
350 
351  /* reset counter */
352  c->mc_frame_counter = 0;
353 
354  if (req_size > buf_size) {
355  av_log(avctx, AV_LOG_ERROR, "buf size too small (need %d, got %d)\n", req_size, buf_size);
356  return -1;
357  }
358  return req_size;
359  }
360  return 0;
361 }
362 
364  .name = "a64multi",
365  .type = AVMEDIA_TYPE_VIDEO,
366  .id = CODEC_ID_A64_MULTI,
367  .priv_data_size = sizeof(A64Context),
369  .encode = a64multi_encode_frame,
371  .pix_fmts = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},
372  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
373  .capabilities = CODEC_CAP_DELAY,
374 };
375 
377  .name = "a64multi5",
378  .type = AVMEDIA_TYPE_VIDEO,
379  .id = CODEC_ID_A64_MULTI5,
380  .priv_data_size = sizeof(A64Context),
382  .encode = a64multi_encode_frame,
384  .pix_fmts = (const enum PixelFormat[]) {PIX_FMT_GRAY8, PIX_FMT_NONE},
385  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
386  .capabilities = CODEC_CAP_DELAY,
387 };