qtrleenc.c
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1 /*
2  * Quicktime Animation (RLE) Video Encoder
3  * Copyright (C) 2007 Clemens Fruhwirth
4  * Copyright (C) 2007 Alexis Ballier
5  *
6  * This file is based on flashsvenc.c.
7  *
8  * This file is part of Libav.
9  *
10  * Libav is free software; you can redistribute it and/or
11  * modify it under the terms of the GNU Lesser General Public
12  * License as published by the Free Software Foundation; either
13  * version 2.1 of the License, or (at your option) any later version.
14  *
15  * Libav is distributed in the hope that it will be useful,
16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18  * Lesser General Public License for more details.
19  *
20  * You should have received a copy of the GNU Lesser General Public
21  * License along with Libav; if not, write to the Free Software
22  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23  */
24 
25 #include "libavutil/imgutils.h"
26 #include "avcodec.h"
27 #include "bytestream.h"
28 
30 #define MAX_RLE_BULK 127
31 
32 #define MAX_RLE_REPEAT 128
33 
34 #define MAX_RLE_SKIP 254
35 
36 typedef struct QtrleEncContext {
41  unsigned int max_buf_size;
51  signed char *rlecode_table;
59  uint8_t* skip_table;
61 
63 {
64  QtrleEncContext *s = avctx->priv_data;
65 
66  if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0) {
67  return -1;
68  }
69  s->avctx=avctx;
70 
71  switch (avctx->pix_fmt) {
72  case PIX_FMT_RGB555BE:
73  s->pixel_size = 2;
74  break;
75  case PIX_FMT_RGB24:
76  s->pixel_size = 3;
77  break;
78  case PIX_FMT_ARGB:
79  s->pixel_size = 4;
80  break;
81  default:
82  av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
83  break;
84  }
85  avctx->bits_per_coded_sample = s->pixel_size*8;
86 
88  s->skip_table = av_mallocz(s->avctx->width);
89  s->length_table = av_mallocz((s->avctx->width + 1)*sizeof(int));
90  if (!s->skip_table || !s->length_table || !s->rlecode_table) {
91  av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
92  return -1;
93  }
94  if (avpicture_alloc(&s->previous_frame, avctx->pix_fmt, avctx->width, avctx->height) < 0) {
95  av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
96  return -1;
97  }
98 
99  s->max_buf_size = s->avctx->width*s->avctx->height*s->pixel_size /* image base material */
100  + 15 /* header + footer */
101  + s->avctx->height*2 /* skip code+rle end */
102  + s->avctx->width/MAX_RLE_BULK + 1 /* rle codes */;
103  avctx->coded_frame = &s->frame;
104  return 0;
105 }
106 
110 static void qtrle_encode_line(QtrleEncContext *s, AVFrame *p, int line, uint8_t **buf)
111 {
112  int width=s->avctx->width;
113  int i;
114  signed char rlecode;
115 
116  /* We will use it to compute the best bulk copy sequence */
117  unsigned int bulkcount;
118  /* This will be the number of pixels equal to the preivous frame one's
119  * starting from the ith pixel */
120  unsigned int skipcount;
121  /* This will be the number of consecutive equal pixels in the current
122  * frame, starting from the ith one also */
123  unsigned int av_uninit(repeatcount);
124 
125  /* The cost of the three different possibilities */
126  int total_bulk_cost;
127  int total_skip_cost;
128  int total_repeat_cost;
129 
130  int temp_cost;
131  int j;
132 
133  uint8_t *this_line = p-> data[0] + line*p-> linesize[0] +
134  (width - 1)*s->pixel_size;
135  uint8_t *prev_line = s->previous_frame.data[0] + line*s->previous_frame.linesize[0] +
136  (width - 1)*s->pixel_size;
137 
138  s->length_table[width] = 0;
139  skipcount = 0;
140 
141  for (i = width - 1; i >= 0; i--) {
142 
143  if (!s->frame.key_frame && !memcmp(this_line, prev_line, s->pixel_size))
144  skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
145  else
146  skipcount = 0;
147 
148  total_skip_cost = s->length_table[i + skipcount] + 2;
149  s->skip_table[i] = skipcount;
150 
151 
152  if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
153  repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
154  else
155  repeatcount = 1;
156 
157  total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
158 
159  /* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
160  * so let's make it aware */
161  if (i == 0) {
162  total_skip_cost--;
163  total_repeat_cost++;
164  }
165 
166  if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
167  /* repeat is the best */
168  s->length_table[i] = total_repeat_cost;
169  s->rlecode_table[i] = -repeatcount;
170  }
171  else if (skipcount > 0) {
172  /* skip is the best choice here */
173  s->length_table[i] = total_skip_cost;
174  s->rlecode_table[i] = 0;
175  }
176  else {
177  /* We cannot do neither skip nor repeat
178  * thus we search for the best bulk copy to do */
179 
180  int limit = FFMIN(width - i, MAX_RLE_BULK);
181 
182  temp_cost = 1 + s->pixel_size + !i;
183  total_bulk_cost = INT_MAX;
184 
185  for (j = 1; j <= limit; j++) {
186  if (s->length_table[i + j] + temp_cost < total_bulk_cost) {
187  /* We have found a better bulk copy ... */
188  total_bulk_cost = s->length_table[i + j] + temp_cost;
189  bulkcount = j;
190  }
191  temp_cost += s->pixel_size;
192  }
193 
194  s->length_table[i] = total_bulk_cost;
195  s->rlecode_table[i] = bulkcount;
196  }
197 
198  this_line -= s->pixel_size;
199  prev_line -= s->pixel_size;
200  }
201 
202  /* Good ! Now we have the best sequence for this line, let's ouput it */
203 
204  /* We do a special case for the first pixel so that we avoid testing it in
205  * the whole loop */
206 
207  i=0;
208  this_line = p-> data[0] + line*p->linesize[0];
209 
210  if (s->rlecode_table[0] == 0) {
211  bytestream_put_byte(buf, s->skip_table[0] + 1);
212  i += s->skip_table[0];
213  }
214  else bytestream_put_byte(buf, 1);
215 
216 
217  while (i < width) {
218  rlecode = s->rlecode_table[i];
219  bytestream_put_byte(buf, rlecode);
220  if (rlecode == 0) {
221  /* Write a skip sequence */
222  bytestream_put_byte(buf, s->skip_table[i] + 1);
223  i += s->skip_table[i];
224  }
225  else if (rlecode > 0) {
226  /* bulk copy */
227  bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
228  i += rlecode;
229  }
230  else {
231  /* repeat the bits */
232  bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
233  i -= rlecode;
234  }
235  }
236  bytestream_put_byte(buf, -1); // end RLE line
237 }
238 
240 static int encode_frame(QtrleEncContext *s, AVFrame *p, uint8_t *buf)
241 {
242  int i;
243  int start_line = 0;
244  int end_line = s->avctx->height;
245  uint8_t *orig_buf = buf;
246 
247  if (!s->frame.key_frame) {
248  unsigned line_size = s->avctx->width * s->pixel_size;
249  for (start_line = 0; start_line < s->avctx->height; start_line++)
250  if (memcmp(p->data[0] + start_line*p->linesize[0],
251  s->previous_frame.data[0] + start_line*s->previous_frame.linesize[0],
252  line_size))
253  break;
254 
255  for (end_line=s->avctx->height; end_line > start_line; end_line--)
256  if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
257  s->previous_frame.data[0] + (end_line - 1)*s->previous_frame.linesize[0],
258  line_size))
259  break;
260  }
261 
262  bytestream_put_be32(&buf, 0); // CHUNK SIZE, patched later
263 
264  if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
265  bytestream_put_be16(&buf, 0); // header
266  else {
267  bytestream_put_be16(&buf, 8); // header
268  bytestream_put_be16(&buf, start_line); // starting line
269  bytestream_put_be16(&buf, 0); // unknown
270  bytestream_put_be16(&buf, end_line - start_line); // lines to update
271  bytestream_put_be16(&buf, 0); // unknown
272  }
273  for (i = start_line; i < end_line; i++)
274  qtrle_encode_line(s, p, i, &buf);
275 
276  bytestream_put_byte(&buf, 0); // zero skip code = frame finished
277  AV_WB32(orig_buf, buf - orig_buf); // patch the chunk size
278  return buf - orig_buf;
279 }
280 
281 static int qtrle_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
282 {
283  QtrleEncContext * const s = avctx->priv_data;
284  AVFrame *pict = data;
285  AVFrame * const p = &s->frame;
286  int chunksize;
287 
288  *p = *pict;
289 
290  if (buf_size < s->max_buf_size) {
291  /* Upper bound check for compressed data */
292  av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->max_buf_size);
293  return -1;
294  }
295 
296  if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
297  /* I-Frame */
299  p->key_frame = 1;
300  } else {
301  /* P-Frame */
303  p->key_frame = 0;
304  }
305 
306  chunksize = encode_frame(s, pict, buf);
307 
308  /* save the current frame */
309  av_picture_copy(&s->previous_frame, (AVPicture *)p, avctx->pix_fmt, avctx->width, avctx->height);
310  return chunksize;
311 }
312 
314 {
315  QtrleEncContext *s = avctx->priv_data;
316 
319  av_free(s->length_table);
320  av_free(s->skip_table);
321  return 0;
322 }
323 
325  .name = "qtrle",
326  .type = AVMEDIA_TYPE_VIDEO,
327  .id = CODEC_ID_QTRLE,
328  .priv_data_size = sizeof(QtrleEncContext),
330  .encode = qtrle_encode_frame,
332  .pix_fmts = (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGB555BE, PIX_FMT_ARGB, PIX_FMT_NONE},
333  .long_name = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
334 };