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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 "config_components.h"
28 
29 #include "a64colors.h"
30 #include "a64tables.h"
31 #include "codec_internal.h"
32 #include "elbg.h"
33 #include "encode.h"
34 #include "libavutil/avassert.h"
35 #include "libavutil/common.h"
36 #include "libavutil/intreadwrite.h"
37 
38 #define DITHERSTEPS   8
39 #define CHARSET_CHARS 256
40 #define INTERLACED    1
41 #define CROP_SCREENS  1
42 
43 #define C64XRES 320
44 #define C64YRES 200
45 
46 typedef struct A64Context {
47     /* variables for multicolor modes */
48     struct ELBGContext *elbg;
49     AVLFG randctx;
50     int mc_lifetime;
51     int mc_use_5col;
52     unsigned mc_frame_counter;
53     int *mc_meta_charset;
54     int *mc_charmap;
55     int *mc_best_cb;
56     int mc_luma_vals[5];
57     uint8_t *mc_colram;
58     uint8_t *mc_palette;
59     int mc_pal_size;
60 
61     /* pts of the next packet that will be output */
62     int64_t next_pts;
63 } A64Context;
64 
65 /* gray gradient */
66 static const uint8_t mc_colors[5]={0x0,0xb,0xc,0xf,0x1};
67 
68 /* other possible gradients - to be tested */
69 //static const uint8_t mc_colors[5]={0x0,0x8,0xa,0xf,0x7};
70 //static const uint8_t mc_colors[5]={0x0,0x9,0x8,0xa,0x3};
71 
to_meta_with_crop(AVCodecContext * avctx,const AVFrame * p,int * dest)72 static void to_meta_with_crop(AVCodecContext *avctx,
73                               const AVFrame *p, int *dest)
74 {
75     int blockx, blocky, x, y;
76     int luma = 0;
77     int height = FFMIN(avctx->height, C64YRES);
78     int width  = FFMIN(avctx->width , C64XRES);
79     uint8_t *src = p->data[0];
80 
81     for (blocky = 0; blocky < C64YRES; blocky += 8) {
82         for (blockx = 0; blockx < C64XRES; blockx += 8) {
83             for (y = blocky; y < blocky + 8 && y < C64YRES; y++) {
84                 for (x = blockx; x < blockx + 8 && x < C64XRES; x += 2) {
85                     if(x < width && y < height) {
86                         if (x + 1 < width) {
87                             /* build average over 2 pixels */
88                             luma = (src[(x + 0 + y * p->linesize[0])] +
89                                     src[(x + 1 + y * p->linesize[0])]) / 2;
90                         } else {
91                             luma = src[(x + y * p->linesize[0])];
92                         }
93                         /* write blocks as linear data now so they are suitable for elbg */
94                         dest[0] = luma;
95                     }
96                     dest++;
97                 }
98             }
99         }
100     }
101 }
102 
render_charset(AVCodecContext * avctx,uint8_t * charset,uint8_t * colrammap)103 static void render_charset(AVCodecContext *avctx, uint8_t *charset,
104                            uint8_t *colrammap)
105 {
106     A64Context *c = avctx->priv_data;
107     uint8_t row1, row2;
108     int charpos, x, y;
109     int a, b;
110     uint8_t pix;
111     int lowdiff, highdiff;
112     int *best_cb = c->mc_best_cb;
113     uint8_t index1[256];
114     uint8_t index2[256];
115     uint8_t dither[256];
116     int i;
117     int distance;
118 
119     /* Generate lookup-tables for dither and index before looping.
120      * This code relies on c->mc_luma_vals[c->mc_pal_size - 1] being
121      * the maximum of all the mc_luma_vals values and on the minimum
122      * being zero; this ensures that dither is properly initialized. */
123     i = 0;
124     for (a=0; a < 256; a++) {
125         if(i < c->mc_pal_size -1 && a == c->mc_luma_vals[i + 1]) {
126             distance = c->mc_luma_vals[i + 1] - c->mc_luma_vals[i];
127             for(b = 0; b <= distance; b++) {
128                   dither[c->mc_luma_vals[i] + b] = b * (DITHERSTEPS - 1) / distance;
129             }
130             i++;
131         }
132         if(i >= c->mc_pal_size - 1) dither[a] = 0;
133         index1[a] = i;
134         index2[a] = FFMIN(i + 1, c->mc_pal_size - 1);
135     }
136 
137     /* and render charset */
138     for (charpos = 0; charpos < CHARSET_CHARS; charpos++) {
139         lowdiff  = 0;
140         highdiff = 0;
141         for (y = 0; y < 8; y++) {
142             row1 = 0; row2 = 0;
143             for (x = 0; x < 4; x++) {
144                 pix = best_cb[y * 4 + x];
145 
146                 /* accumulate error for brightest/darkest color */
147                 if (index1[pix] >= 3)
148                     highdiff += pix - c->mc_luma_vals[3];
149                 if (index1[pix] < 1)
150                     lowdiff += c->mc_luma_vals[1] - pix;
151 
152                 row1 <<= 2;
153 
154                 if (INTERLACED) {
155                     row2 <<= 2;
156                     if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 0][x & 3])
157                         row1 |= 3-(index2[pix] & 3);
158                     else
159                         row1 |= 3-(index1[pix] & 3);
160 
161                     if (interlaced_dither_patterns[dither[pix]][(y & 3) * 2 + 1][x & 3])
162                         row2 |= 3-(index2[pix] & 3);
163                     else
164                         row2 |= 3-(index1[pix] & 3);
165                 }
166                 else {
167                     if (multi_dither_patterns[dither[pix]][(y & 3)][x & 3])
168                         row1 |= 3-(index2[pix] & 3);
169                     else
170                         row1 |= 3-(index1[pix] & 3);
171                 }
172             }
173             charset[y+0x000] = row1;
174             if (INTERLACED) charset[y+0x800] = row2;
175         }
176         /* do we need to adjust pixels? */
177         if (highdiff > 0 && lowdiff > 0 && c->mc_use_5col) {
178             if (lowdiff > highdiff) {
179                 for (x = 0; x < 32; x++)
180                     best_cb[x] = FFMIN(c->mc_luma_vals[3], best_cb[x]);
181             } else {
182                 for (x = 0; x < 32; x++)
183                     best_cb[x] = FFMAX(c->mc_luma_vals[1], best_cb[x]);
184             }
185             charpos--;          /* redo now adjusted char */
186         /* no adjustment needed, all fine */
187         } else {
188             /* advance pointers */
189             best_cb += 32;
190             charset += 8;
191 
192             /* remember colorram value */
193             colrammap[charpos] = (highdiff > 0);
194         }
195     }
196 }
197 
a64multi_close_encoder(AVCodecContext * avctx)198 static av_cold int a64multi_close_encoder(AVCodecContext *avctx)
199 {
200     A64Context *c = avctx->priv_data;
201 
202     avpriv_elbg_free(&c->elbg);
203 
204     av_freep(&c->mc_meta_charset);
205     av_freep(&c->mc_best_cb);
206     av_freep(&c->mc_charmap);
207     av_freep(&c->mc_colram);
208     return 0;
209 }
210 
a64multi_encode_init(AVCodecContext * avctx)211 static av_cold int a64multi_encode_init(AVCodecContext *avctx)
212 {
213     A64Context *c = avctx->priv_data;
214     int a;
215     av_lfg_init(&c->randctx, 1);
216 
217     if (avctx->global_quality < 1) {
218         c->mc_lifetime = 4;
219     } else {
220         c->mc_lifetime = avctx->global_quality / FF_QP2LAMBDA;
221     }
222 
223     av_log(avctx, AV_LOG_INFO, "charset lifetime set to %d frame(s)\n", c->mc_lifetime);
224 
225     c->mc_frame_counter = 0;
226     c->mc_use_5col      = avctx->codec->id == AV_CODEC_ID_A64_MULTI5;
227     c->mc_pal_size      = 4 + c->mc_use_5col;
228 
229     /* precalc luma values for later use */
230     for (a = 0; a < c->mc_pal_size; a++) {
231         c->mc_luma_vals[a]=a64_palette[mc_colors[a]][0] * 0.30 +
232                            a64_palette[mc_colors[a]][1] * 0.59 +
233                            a64_palette[mc_colors[a]][2] * 0.11;
234     }
235 
236     if (!(c->mc_meta_charset = av_calloc(c->mc_lifetime, 32000 * sizeof(int))) ||
237        !(c->mc_best_cb       = av_malloc(CHARSET_CHARS * 32 * sizeof(int)))     ||
238        !(c->mc_charmap       = av_calloc(c->mc_lifetime, 1000 * sizeof(int))) ||
239        !(c->mc_colram        = av_mallocz(CHARSET_CHARS * sizeof(uint8_t)))) {
240         av_log(avctx, AV_LOG_ERROR, "Failed to allocate buffer memory.\n");
241         return AVERROR(ENOMEM);
242     }
243 
244     /* set up extradata */
245     if (!(avctx->extradata = av_mallocz(8 * 4 + AV_INPUT_BUFFER_PADDING_SIZE))) {
246         av_log(avctx, AV_LOG_ERROR, "Failed to allocate memory for extradata.\n");
247         return AVERROR(ENOMEM);
248     }
249     avctx->extradata_size = 8 * 4;
250     AV_WB32(avctx->extradata, c->mc_lifetime);
251     AV_WB32(avctx->extradata + 16, INTERLACED);
252 
253     if (!avctx->codec_tag)
254          avctx->codec_tag = AV_RL32("a64m");
255 
256     c->next_pts = AV_NOPTS_VALUE;
257 
258     return 0;
259 }
260 
a64_compress_colram(unsigned char * buf,int * charmap,uint8_t * colram)261 static void a64_compress_colram(unsigned char *buf, int *charmap, uint8_t *colram)
262 {
263     int a;
264     uint8_t temp;
265     /* only needs to be done in 5col mode */
266     /* XXX could be squeezed to 0x80 bytes */
267     for (a = 0; a < 256; a++) {
268         temp  = colram[charmap[a + 0x000]] << 0;
269         temp |= colram[charmap[a + 0x100]] << 1;
270         temp |= colram[charmap[a + 0x200]] << 2;
271         if (a < 0xe8) temp |= colram[charmap[a + 0x300]] << 3;
272         buf[a] = temp << 2;
273     }
274 }
275 
a64multi_encode_frame(AVCodecContext * avctx,AVPacket * pkt,const AVFrame * p,int * got_packet)276 static int a64multi_encode_frame(AVCodecContext *avctx, AVPacket *pkt,
277                                  const AVFrame *p, int *got_packet)
278 {
279     A64Context *c = avctx->priv_data;
280 
281     int frame;
282     int x, y;
283     int b_height;
284     int b_width;
285 
286     int req_size, ret;
287     uint8_t *buf = NULL;
288 
289     int *charmap     = c->mc_charmap;
290     uint8_t *colram  = c->mc_colram;
291     int *meta        = c->mc_meta_charset;
292     int *best_cb     = c->mc_best_cb;
293 
294     int charset_size = 0x800 * (INTERLACED + 1);
295     int colram_size  = 0x100 * c->mc_use_5col;
296     int screen_size;
297 
298     if(CROP_SCREENS) {
299         b_height = FFMIN(avctx->height,C64YRES) >> 3;
300         b_width  = FFMIN(avctx->width ,C64XRES) >> 3;
301         screen_size = b_width * b_height;
302     } else {
303         b_height = C64YRES >> 3;
304         b_width  = C64XRES >> 3;
305         screen_size = 0x400;
306     }
307 
308     /* no data, means end encoding asap */
309     if (!p) {
310         /* all done, end encoding */
311         if (!c->mc_lifetime) return 0;
312         /* no more frames in queue, prepare to flush remaining frames */
313         if (!c->mc_frame_counter) {
314             c->mc_lifetime = 0;
315         }
316         /* still frames in queue so limit lifetime to remaining frames */
317         else c->mc_lifetime = c->mc_frame_counter;
318     /* still new data available */
319     } else {
320         /* fill up mc_meta_charset with data until lifetime exceeds */
321         if (c->mc_frame_counter < c->mc_lifetime) {
322             to_meta_with_crop(avctx, p, meta + 32000 * c->mc_frame_counter);
323             c->mc_frame_counter++;
324             if (c->next_pts == AV_NOPTS_VALUE)
325                 c->next_pts = p->pts;
326             /* lifetime is not reached so wait for next frame first */
327             return 0;
328         }
329     }
330 
331     /* lifetime reached so now convert X frames at once */
332     if (c->mc_frame_counter == c->mc_lifetime) {
333         req_size = 0;
334         /* any frames to encode? */
335         if (c->mc_lifetime) {
336             int alloc_size = charset_size + c->mc_lifetime*(screen_size + colram_size);
337             if ((ret = ff_get_encode_buffer(avctx, pkt, alloc_size, 0)) < 0)
338                 return ret;
339             buf = pkt->data;
340 
341             /* calc optimal new charset + charmaps */
342             ret = avpriv_elbg_do(&c->elbg, meta, 32, 1000 * c->mc_lifetime,
343                                  best_cb, CHARSET_CHARS, 50, charmap, &c->randctx, 0);
344             if (ret < 0)
345                 return ret;
346 
347             /* create colorram map and a c64 readable charset */
348             render_charset(avctx, buf, colram);
349 
350             /* advance pointers */
351             buf      += charset_size;
352             req_size += 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;
387         c->next_pts         = AV_NOPTS_VALUE;
388 
389         av_assert0(pkt->size == req_size);
390         *got_packet = !!req_size;
391     }
392     return 0;
393 }
394 
395 #if CONFIG_A64MULTI_ENCODER
396 const FFCodec ff_a64multi_encoder = {
397     .p.name         = "a64multi",
398     .p.long_name    = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64"),
399     .p.type         = AVMEDIA_TYPE_VIDEO,
400     .p.id           = AV_CODEC_ID_A64_MULTI,
401     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
402     .priv_data_size = sizeof(A64Context),
403     .init           = a64multi_encode_init,
404     FF_CODEC_ENCODE_CB(a64multi_encode_frame),
405     .close          = a64multi_close_encoder,
406     .p.pix_fmts     = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
407     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
408 };
409 #endif
410 #if CONFIG_A64MULTI5_ENCODER
411 const FFCodec ff_a64multi5_encoder = {
412     .p.name         = "a64multi5",
413     .p.long_name    = NULL_IF_CONFIG_SMALL("Multicolor charset for Commodore 64, extended with 5th color (colram)"),
414     .p.type         = AVMEDIA_TYPE_VIDEO,
415     .p.id           = AV_CODEC_ID_A64_MULTI5,
416     .p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
417     .priv_data_size = sizeof(A64Context),
418     .init           = a64multi_encode_init,
419     FF_CODEC_ENCODE_CB(a64multi_encode_frame),
420     .close          = a64multi_close_encoder,
421     .p.pix_fmts     = (const enum AVPixelFormat[]) {AV_PIX_FMT_GRAY8, AV_PIX_FMT_NONE},
422     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
423 };
424 #endif
425