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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  /* variables for multicolor modes */
47  unsigned mc_frame_counter;
49  int *mc_charmap;
50  int *mc_best_cb;
51  int mc_luma_vals[5];
56 
57  /* pts of the next packet that will be output */
58  int64_t next_pts;
59 } A64Context;
60 
61 /* gray gradient */
62 static const int mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
63 
64 /* other possible gradients - to be tested */
65 //static const int mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
66 //static const int mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
67 
68 static void to_meta_with_crop(AVCodecContext *avctx, AVFrame *p, int *dest)
69 {
70  int blockx, blocky, x, y;
71  int luma = 0;
72  int height = FFMIN(avctx->height, C64YRES);
73  int width = FFMIN(avctx->width , C64XRES);
74  uint8_t *src = p->data[0];
75 
76  for (blocky = 0; blocky < C64YRES; blocky += 8) {
77  for (blockx = 0; blockx < C64XRES; blockx += 8) {
78  for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
79  for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
80  if(x < width && y < height) {
81  /* build average over 2 pixels */
82  luma = (src[(x + 0 + y * p->linesize[0])] +
83  src[(x + 1 + y * p->linesize[0])]) / 2;
84  /* write blocks as linear data now so they are suitable for elbg */
85  dest[0] = luma;
86  }
87  dest++;
88  }
89  }
90  }
91  }
92 }
93 
94 static void render_charset(AVCodecContext *avctx, uint8_t *charset,
95  uint8_t *colrammap)
96 {
97  A64Context *c = avctx->priv_data;
98  uint8_t row1, row2;
99  int charpos, x, y;
100  int a, b;
101  uint8_t pix;
102  int lowdiff, highdiff;
103  int *best_cb = c->mc_best_cb;
104  static uint8_t index1[256];
105  static uint8_t index2[256];
106  static uint8_t dither[256];
107  int i;
108  int distance;
109 
110  /* generate lookup-tables for dither and index before looping */
111  i = 0;
112  for (a=0; a < 256; a++) {
113  if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
114  distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
115  for(b = 0; b <= distance; b++) {
116  dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
117  }
118  i++;
119  }
120  if(i >= c->mc_pal_size - 1) dither[a] = 0;
121  index1[a] = i;
122  index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
123  }
124 
125  /* and render charset */
126  for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
127  lowdiff = 0;
128  highdiff = 0;
129  for (y = 0; y < 8; y++) {
130  row1 = 0; row2 = 0;
131  for (x = 0; x < 4; x++) {
132  pix = best_cb[y * 4 + x];
133 
134  /* accumulate error for brightest/darkest color */
135  if (index1[pix] >= 3)
136  highdiff += pix - c->mc_luma_vals[3];
137  if (index1[pix] < 1)
138  lowdiff += c->mc_luma_vals[1] - pix;
139 
140  row1 <<= 2;
141 
142  if (INTERLACED) {
143  row2 <<= 2;
144  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
145  row1 |= 3-(index2[pix] & 3);
146  else
147  row1 |= 3-(index1[pix] & 3);
148 
149  if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
150  row2 |= 3-(index2[pix] & 3);
151  else
152  row2 |= 3-(index1[pix] & 3);
153  }
154  else {
155  if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
156  row1 |= 3-(index2[pix] & 3);
157  else
158  row1 |= 3-(index1[pix] & 3);
159  }
160  }
161  charset[y+0x000] = row1;
162  if (INTERLACED) charset[y+0x800] = row2;
163  }
164  /* do we need to adjust pixels? */
165  if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
166  if (lowdiff > highdiff) {
167  for (x = 0; x < 32; x++)
168  best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
169  } else {
170  for (x = 0; x < 32; x++)
171  best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
172  }
173  charpos--; /* redo now adjusted char */
174  /* no adjustment needed, all fine */
175  } else {
176  /* advance pointers */
177  best_cb += 32;
178  charset += 8;
179 
180  /* remember colorram value */
181  colrammap[charpos] = (highdiff > 0);
182  }
183  }
184 }
185 
187 {
188  A64Context *c = avctx->priv_data;
189  av_frame_free(&avctx->coded_frame);
191  av_freep(&c->mc_best_cb);
192  av_freep(&c->mc_charset);
193  av_freep(&c->mc_charmap);
194  av_freep(&c->mc_colram);
195  return 0;
196 }
197 
199 {
200  A64Context *c = avctx->priv_data;
201  int a;
202  av_lfg_init(&c->randctx, 1);
203 
204  if (avctx->global_quality < 1) {
205  c->mc_lifetime = 4;
206  } else {
207  c->mc_lifetime = avctx->global_quality /= FF_QP2LAMBDA;
208  }
209 
210  av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
211 
212  c->mc_frame_counter = 0;
213  c->mc_use_5col = avctx->codec->id == AV_CODEC_ID_A64_MULTI5;
214  c->mc_pal_size = 4 + c->mc_use_5col;
215 
216  /* precalc luma values for later use */
217  for (a = 0; a < c->mc_pal_size; a++) {
218  c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
219  a64_palette[mc_colors[a]][1] * 0.59 +
220  a64_palette[mc_colors[a]][2] * 0.11;
221  }
222 
223  if (!(c->mc_meta_charset = av_malloc_array(c->mc_lifetime, 32000 * sizeof(int))) ||
224  !(c->mc_best_cb = av_malloc(CHARSET_CHARS * 32 * sizeof(int))) ||
225  !(c->mc_charmap = av_mallocz_array(c->mc_lifetime, 1000 * sizeof(int))) ||
226  !(c->mc_colram = av_mallocz(CHARSET_CHARS * sizeof(uint8_t))) ||
227  !(c->mc_charset = av_malloc(0x800 * (INTERLACED+1) * sizeof(uint8_t)))) {
228  av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
229  return AVERROR(ENOMEM);
230  }
231 
232  /* set up extradata */
233  if (!(avctx->extradata = av_mallocz(8 * 4 + FF_INPUT_BUFFER_PADDING_SIZE))) {
234  av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
235  return AVERROR(ENOMEM);
236  }
237  avctx->extradata_size = 8 * 4;
238  AV_WB32(avctx->extradata, c->mc_lifetime);
239  AV_WB32(avctx->extradata + 16, INTERLACED);
240 
241  avctx->coded_frame = av_frame_alloc();
242  if (!avctx->coded_frame) {
243  a64multi_close_encoder(avctx);
244  return AVERROR(ENOMEM);
245  }
246 
248  avctx->coded_frame->key_frame = 1;
249  if (!avctx->codec_tag)
250  avctx->codec_tag = AV_RL32("a64m");
251 
253 
254  return 0;
255 }
256 
257 static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
258 {
259  int a;
260  uint8_t temp;
261  /* only needs to be done in 5col mode */
262  /* XXX could be squeezed to 0x80 bytes */
263  for (a = 0; a < 256; a++) {
264  temp = colram[charmap[a + 0x000]] << 0;
265  temp |= colram[charmap[a + 0x100]] << 1;
266  temp |= colram[charmap[a + 0x200]] << 2;
267  if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
268  buf[a] = temp << 2;
269  }
270 }
271 
273  const AVFrame *pict, int *got_packet)
274 {
275  A64Context *c = avctx->priv_data;
276  AVFrame *const p = avctx->coded_frame;
277 
278  int frame;
279  int x, y;
280  int b_height;
281  int b_width;
282 
283  int req_size, ret;
284  uint8_t *buf = NULL;
285 
286  int *charmap = c->mc_charmap;
287  uint8_t *colram = c->mc_colram;
288  uint8_t *charset = c->mc_charset;
289  int *meta = c->mc_meta_charset;
290  int *best_cb = c->mc_best_cb;
291 
292  int charset_size = 0x800 * (INTERLACED + 1);
293  int colram_size = 0x100 * c->mc_use_5col;
294  int screen_size;
295 
296  if(CROP_SCREENS) {
297  b_height = FFMIN(avctx->height,C64YRES) >> 3;
298  b_width = FFMIN(avctx->width ,C64XRES) >> 3;
299  screen_size = b_width * b_height;
300  } else {
301  b_height = C64YRES >> 3;
302  b_width = C64XRES >> 3;
303  screen_size = 0x400;
304  }
305 
306  /* no data, means end encoding asap */
307  if (!pict) {
308  /* all done, end encoding */
309  if (!c->mc_lifetime) return 0;
310  /* no more frames in queue, prepare to flush remaining frames */
311  if (!c->mc_frame_counter) {
312  c->mc_lifetime = 0;
313  }
314  /* still frames in queue so limit lifetime to remaining frames */
315  else c->mc_lifetime = c->mc_frame_counter;
316  /* still new data available */
317  } else {
318  /* fill up mc_meta_charset with data until lifetime exceeds */
319  if (c->mc_frame_counter < c->mc_lifetime) {
320  *p = *pict;
322  p->key_frame = 1;
323  to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
324  c->mc_frame_counter++;
325  if (c->next_pts == AV_NOPTS_VALUE)
326  c->next_pts = pict->pts;
327  /* lifetime is not reached so wait for next frame first */
328  return 0;
329  }
330  }
331 
332  /* lifetime reached so now convert X frames at once */
333  if (c->mc_frame_counter == c->mc_lifetime) {
334  req_size = 0;
335  /* any frames to encode? */
336  if (c->mc_lifetime) {
337  req_size = charset_size + c->mc_lifetime*(screen_size + colram_size);
338  if ((ret = ff_alloc_packet2(avctx, pkt, req_size)) < 0)
339  return ret;
340  buf = pkt->data;
341 
342  /* calc optimal new charset + charmaps */
343  ret = avpriv_init_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb,
344  CHARSET_CHARS, 50, charmap, &c->randctx);
345  if (ret < 0)
346  return ret;
347  ret = avpriv_do_elbg(meta, 32, 1000 * c->mc_lifetime, best_cb,
348  CHARSET_CHARS, 50, charmap, &c->randctx);
349  if (ret < 0)
350  return ret;
351 
352  /* create colorram map and a c64 readable charset */
353  render_charset(avctx, charset, colram);
354 
355  /* copy charset to buf */
356  memcpy(buf, charset, charset_size);
357 
358  /* advance pointers */
359  buf += charset_size;
360  }
361 
362  /* write x frames to buf */
363  for (frame = 0; frame < c->mc_lifetime; frame++) {
364  /* copy charmap to buf. buf is uchar*, charmap is int*, so no memcpy here, sorry */
365  for (y = 0; y < b_height; y++) {
366  for (x = 0; x < b_width; x++) {
367  buf[y * b_width + x] = charmap[y * b_width + x];
368  }
369  }
370  /* advance pointers */
371  buf += screen_size;
372  req_size += screen_size;
373 
374  /* compress and copy colram to buf */
375  if (c->mc_use_5col) {
376  a64_compress_colram(buf, charmap, colram);
377  /* advance pointers */
378  buf += colram_size;
379  req_size += colram_size;
380  }
381 
382  /* advance to next charmap */
383  charmap += 1000;
384  }
385 
386  AV_WB32(avctx->extradata + 4, c->mc_frame_counter);
387  AV_WB32(avctx->extradata + 8, charset_size);
388  AV_WB32(avctx->extradata + 12, screen_size + colram_size);
389 
390  /* reset counter */
391  c->mc_frame_counter = 0;
392 
393  pkt->pts = pkt->dts = c->next_pts;
395 
396  pkt->size = req_size;
397  pkt->flags |= AV_PKT_FLAG_KEY;
398  *got_packet = !!req_size;
399  }
400  return 0;
401 }
402 
403 #if CONFIG_A64MULTI_ENCODER
404 AVCodec ff_a64multi_encoder = {
405  .name = "a64multi",
406  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
407  .type = AVMEDIA_TYPE_VIDEO,
408  .id = AV_CODEC_ID_A64_MULTI,
409  .priv_data_size = sizeof(A64Context),
411  .encode2 = a64multi_encode_frame,
412  .close = a64multi_close_encoder,
413  .pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
414  .capabilities = CODEC_CAP_DELAY,
415 };
416 #endif
417 #if CONFIG_A64MULTI5_ENCODER
418 AVCodec ff_a64multi5_encoder = {
419  .name = "a64multi5",
420  .long_name = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
421  .type = AVMEDIA_TYPE_VIDEO,
423  .priv_data_size = sizeof(A64Context),
425  .encode2 = a64multi_encode_frame,
426  .close = a64multi_close_encoder,
427  .pix_fmts = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
428  .capabilities = CODEC_CAP_DELAY,
429 };
430 #endif