zmbvenc.c
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1 /*
2  * Zip Motion Blocks Video (ZMBV) encoder
3  * Copyright (c) 2006 Konstantin Shishkov
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 <stdio.h>
28 #include <stdlib.h>
29 
30 #include "libavutil/common.h"
31 #include "libavutil/intreadwrite.h"
32 #include "avcodec.h"
33 #include "internal.h"
34 
35 #include <zlib.h>
36 
37 #define ZMBV_KEYFRAME 1
38 #define ZMBV_DELTAPAL 2
39 
40 #define ZMBV_BLOCK 16
41 
45 typedef struct ZmbvEncContext {
48 
49  int range;
51  uint8_t pal[768];
52  uint32_t pal2[256]; //for quick comparisons
54  int pstride;
55  int comp_size;
56  int keyint, curfrm;
57  z_stream zstream;
59 
60 static int score_tab[256];
61 
66 static inline int block_cmp(uint8_t *src, int stride, uint8_t *src2, int stride2,
67  int bw, int bh, int *xored)
68 {
69  int sum = 0;
70  int i, j;
71  uint8_t histogram[256] = {0};
72 
73  *xored = 0;
74  for(j = 0; j < bh; j++){
75  for(i = 0; i < bw; i++){
76  int t = src[i] ^ src2[i];
77  histogram[t]++;
78  *xored |= t;
79  }
80  src += stride;
81  src2 += stride2;
82  }
83 
84  for(i = 1; i < 256; i++)
85  sum += score_tab[histogram[i]];
86 
87  return sum;
88 }
89 
93 static int zmbv_me(ZmbvEncContext *c, uint8_t *src, int sstride, uint8_t *prev,
94  int pstride, int x, int y, int *mx, int *my, int *xored)
95 {
96  int dx, dy, tx, ty, tv, bv, bw, bh;
97 
98  *mx = *my = 0;
99  bw = FFMIN(ZMBV_BLOCK, c->avctx->width - x);
100  bh = FFMIN(ZMBV_BLOCK, c->avctx->height - y);
101  bv = block_cmp(src, sstride, prev, pstride, bw, bh, xored);
102  if(!bv) return 0;
103  for(ty = FFMAX(y - c->range, 0); ty < FFMIN(y + c->range, c->avctx->height - bh); ty++){
104  for(tx = FFMAX(x - c->range, 0); tx < FFMIN(x + c->range, c->avctx->width - bw); tx++){
105  if(tx == x && ty == y) continue; // we already tested this block
106  dx = tx - x;
107  dy = ty - y;
108  tv = block_cmp(src, sstride, prev + dx + dy*pstride, pstride, bw, bh, xored);
109  if(tv < bv){
110  bv = tv;
111  *mx = dx;
112  *my = dy;
113  if(!bv) return 0;
114  }
115  }
116  }
117  return bv;
118 }
119 
120 static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
121  const AVFrame *pict, int *got_packet)
122 {
123  ZmbvEncContext * const c = avctx->priv_data;
124  AVFrame * const p = &c->pic;
125  uint8_t *src, *prev, *buf;
126  uint32_t *palptr;
127  int keyframe, chpal;
128  int fl;
129  int work_size = 0, pkt_size;
130  int bw, bh;
131  int i, j, ret;
132 
133  keyframe = !c->curfrm;
134  c->curfrm++;
135  if(c->curfrm == c->keyint)
136  c->curfrm = 0;
137  *p = *pict;
139  p->key_frame= keyframe;
140  chpal = !keyframe && memcmp(p->data[1], c->pal2, 1024);
141 
142  palptr = (uint32_t*)p->data[1];
143  src = p->data[0];
144  prev = c->prev;
145  if(chpal){
146  uint8_t tpal[3];
147  for(i = 0; i < 256; i++){
148  AV_WB24(tpal, palptr[i]);
149  c->work_buf[work_size++] = tpal[0] ^ c->pal[i * 3 + 0];
150  c->work_buf[work_size++] = tpal[1] ^ c->pal[i * 3 + 1];
151  c->work_buf[work_size++] = tpal[2] ^ c->pal[i * 3 + 2];
152  c->pal[i * 3 + 0] = tpal[0];
153  c->pal[i * 3 + 1] = tpal[1];
154  c->pal[i * 3 + 2] = tpal[2];
155  }
156  memcpy(c->pal2, p->data[1], 1024);
157  }
158  if(keyframe){
159  for(i = 0; i < 256; i++){
160  AV_WB24(c->pal+(i*3), palptr[i]);
161  }
162  memcpy(c->work_buf, c->pal, 768);
163  memcpy(c->pal2, p->data[1], 1024);
164  work_size = 768;
165  for(i = 0; i < avctx->height; i++){
166  memcpy(c->work_buf + work_size, src, avctx->width);
167  src += p->linesize[0];
168  work_size += avctx->width;
169  }
170  }else{
171  int x, y, bh2, bw2, xored;
172  uint8_t *tsrc, *tprev;
173  uint8_t *mv;
174  int mx, my;
175 
176  bw = (avctx->width + ZMBV_BLOCK - 1) / ZMBV_BLOCK;
177  bh = (avctx->height + ZMBV_BLOCK - 1) / ZMBV_BLOCK;
178  mv = c->work_buf + work_size;
179  memset(c->work_buf + work_size, 0, (bw * bh * 2 + 3) & ~3);
180  work_size += (bw * bh * 2 + 3) & ~3;
181  /* for now just XOR'ing */
182  for(y = 0; y < avctx->height; y += ZMBV_BLOCK) {
183  bh2 = FFMIN(avctx->height - y, ZMBV_BLOCK);
184  for(x = 0; x < avctx->width; x += ZMBV_BLOCK, mv += 2) {
185  bw2 = FFMIN(avctx->width - x, ZMBV_BLOCK);
186 
187  tsrc = src + x;
188  tprev = prev + x;
189 
190  zmbv_me(c, tsrc, p->linesize[0], tprev, c->pstride, x, y, &mx, &my, &xored);
191  mv[0] = (mx << 1) | !!xored;
192  mv[1] = my << 1;
193  tprev += mx + my * c->pstride;
194  if(xored){
195  for(j = 0; j < bh2; j++){
196  for(i = 0; i < bw2; i++)
197  c->work_buf[work_size++] = tsrc[i] ^ tprev[i];
198  tsrc += p->linesize[0];
199  tprev += c->pstride;
200  }
201  }
202  }
203  src += p->linesize[0] * ZMBV_BLOCK;
204  prev += c->pstride * ZMBV_BLOCK;
205  }
206  }
207  /* save the previous frame */
208  src = p->data[0];
209  prev = c->prev;
210  for(i = 0; i < avctx->height; i++){
211  memcpy(prev, src, avctx->width);
212  prev += c->pstride;
213  src += p->linesize[0];
214  }
215 
216  if (keyframe)
217  deflateReset(&c->zstream);
218 
219  c->zstream.next_in = c->work_buf;
220  c->zstream.avail_in = work_size;
221  c->zstream.total_in = 0;
222 
223  c->zstream.next_out = c->comp_buf;
224  c->zstream.avail_out = c->comp_size;
225  c->zstream.total_out = 0;
226  if(deflate(&c->zstream, Z_SYNC_FLUSH) != Z_OK){
227  av_log(avctx, AV_LOG_ERROR, "Error compressing data\n");
228  return -1;
229  }
230 
231  pkt_size = c->zstream.total_out + 1 + 6*keyframe;
232  if ((ret = ff_alloc_packet(pkt, pkt_size)) < 0) {
233  av_log(avctx, AV_LOG_ERROR, "Error getting packet of size %d.\n", pkt_size);
234  return ret;
235  }
236  buf = pkt->data;
237 
238  fl = (keyframe ? ZMBV_KEYFRAME : 0) | (chpal ? ZMBV_DELTAPAL : 0);
239  *buf++ = fl;
240  if (keyframe) {
241  *buf++ = 0; // hi ver
242  *buf++ = 1; // lo ver
243  *buf++ = 1; // comp
244  *buf++ = 4; // format - 8bpp
245  *buf++ = ZMBV_BLOCK; // block width
246  *buf++ = ZMBV_BLOCK; // block height
247  }
248  memcpy(buf, c->comp_buf, c->zstream.total_out);
249 
250  pkt->flags |= AV_PKT_FLAG_KEY*keyframe;
251  *got_packet = 1;
252 
253  return 0;
254 }
255 
256 
261 {
262  ZmbvEncContext * const c = avctx->priv_data;
263  int zret; // Zlib return code
264  int i;
265  int lvl = 9;
266 
267  for(i=1; i<256; i++)
268  score_tab[i]= -i * log(i/(double)(ZMBV_BLOCK*ZMBV_BLOCK)) * (256/M_LN2);
269 
270  c->avctx = avctx;
271 
272  c->curfrm = 0;
273  c->keyint = avctx->keyint_min;
274  c->range = 8;
275  if(avctx->me_range > 0)
276  c->range = FFMIN(avctx->me_range, 127);
277 
278  if(avctx->compression_level >= 0)
279  lvl = avctx->compression_level;
280  if(lvl < 0 || lvl > 9){
281  av_log(avctx, AV_LOG_ERROR, "Compression level should be 0-9, not %i\n", lvl);
282  return AVERROR(EINVAL);
283  }
284 
285  // Needed if zlib unused or init aborted before deflateInit
286  memset(&c->zstream, 0, sizeof(z_stream));
287  c->comp_size = avctx->width * avctx->height + 1024 +
288  ((avctx->width + ZMBV_BLOCK - 1) / ZMBV_BLOCK) * ((avctx->height + ZMBV_BLOCK - 1) / ZMBV_BLOCK) * 2 + 4;
289  if ((c->work_buf = av_malloc(c->comp_size)) == NULL) {
290  av_log(avctx, AV_LOG_ERROR, "Can't allocate work buffer.\n");
291  return AVERROR(ENOMEM);
292  }
293  /* Conservative upper bound taken from zlib v1.2.1 source via lcl.c */
294  c->comp_size = c->comp_size + ((c->comp_size + 7) >> 3) +
295  ((c->comp_size + 63) >> 6) + 11;
296 
297  /* Allocate compression buffer */
298  if ((c->comp_buf = av_malloc(c->comp_size)) == NULL) {
299  av_log(avctx, AV_LOG_ERROR, "Can't allocate compression buffer.\n");
300  return AVERROR(ENOMEM);
301  }
302  c->pstride = FFALIGN(avctx->width, 16);
303  if ((c->prev = av_malloc(c->pstride * avctx->height)) == NULL) {
304  av_log(avctx, AV_LOG_ERROR, "Can't allocate picture.\n");
305  return AVERROR(ENOMEM);
306  }
307 
308  c->zstream.zalloc = Z_NULL;
309  c->zstream.zfree = Z_NULL;
310  c->zstream.opaque = Z_NULL;
311  zret = deflateInit(&c->zstream, lvl);
312  if (zret != Z_OK) {
313  av_log(avctx, AV_LOG_ERROR, "Inflate init error: %d\n", zret);
314  return -1;
315  }
316 
317  avctx->coded_frame = &c->pic;
318 
319  return 0;
320 }
321 
322 
323 
328 {
329  ZmbvEncContext * const c = avctx->priv_data;
330 
331  av_freep(&c->comp_buf);
332  av_freep(&c->work_buf);
333 
334  deflateEnd(&c->zstream);
335  av_freep(&c->prev);
336 
337  return 0;
338 }
339 
341  .name = "zmbv",
342  .type = AVMEDIA_TYPE_VIDEO,
343  .id = AV_CODEC_ID_ZMBV,
344  .priv_data_size = sizeof(ZmbvEncContext),
345  .init = encode_init,
346  .encode2 = encode_frame,
347  .close = encode_end,
348  .pix_fmts = (const enum AVPixelFormat[]){ AV_PIX_FMT_PAL8, AV_PIX_FMT_NONE },
349  .long_name = NULL_IF_CONFIG_SMALL("Zip Motion Blocks Video"),
350 };