Add av_uninit macro to variable to avoid false positive warning:
[libav.git] / libavcodec / qtrleenc.c
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 FFmpeg.
9 *
10 * FFmpeg 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 * FFmpeg 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 FFmpeg; if not, write to the Free Software
22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
23 */
24
25 #include "avcodec.h"
26 #include "bytestream.h"
27
28 /** Maximum RLE code for bulk copy */
29 #define MAX_RLE_BULK 127
30 /** Maximum RLE code for repeat */
31 #define MAX_RLE_REPEAT 128
32 /** Maximum RLE code for skip */
33 #define MAX_RLE_SKIP 254
34
35 typedef struct QtrleEncContext {
36 AVCodecContext *avctx;
37 AVFrame frame;
38 int pixel_size;
39 AVPicture previous_frame;
40 unsigned int max_buf_size;
41 /**
42 * This array will contain at ith position the value of the best RLE code
43 * if the line started at pixel i
44 * There can be 3 values :
45 * skip (0) : skip as much as possible pixels because they are equal to the
46 * previous frame ones
47 * repeat (<-1) : repeat that pixel -rle_code times, still as much as
48 * possible
49 * copy (>0) : copy the raw next rle_code pixels */
50 signed char *rlecode_table;
51 /**
52 * This array will contain the length of the best rle encoding of the line
53 * starting at ith pixel */
54 int *length_table;
55 /**
56 * Will contain at ith position the number of consecutive pixels equal to the previous
57 * frame starting from pixel i */
58 uint8_t* skip_table;
59 } QtrleEncContext;
60
61 static av_cold int qtrle_encode_init(AVCodecContext *avctx)
62 {
63 QtrleEncContext *s = avctx->priv_data;
64
65 if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
66 return -1;
67 }
68 s->avctx=avctx;
69
70 switch (avctx->pix_fmt) {
71 /* case PIX_FMT_RGB555:
72 s->pixel_size = 2;
73 break;*/
74 case PIX_FMT_RGB24:
75 s->pixel_size = 3;
76 break;
77 default:
78 av_log(avctx, AV_LOG_ERROR, "Unsupported colorspace.\n");
79 break;
80 }
81 avctx->bits_per_coded_sample = s->pixel_size*8;
82
83 s->rlecode_table = av_mallocz(s->avctx->width);
84 s->skip_table = av_mallocz(s->avctx->width);
85 s->length_table = av_mallocz((s->avctx->width + 1)*sizeof(int));
86 if (!s->skip_table || !s->length_table || !s->rlecode_table) {
87 av_log(avctx, AV_LOG_ERROR, "Error allocating memory.\n");
88 return -1;
89 }
90 if (avpicture_alloc(&s->previous_frame, avctx->pix_fmt, avctx->width, avctx->height) < 0) {
91 av_log(avctx, AV_LOG_ERROR, "Error allocating picture\n");
92 return -1;
93 }
94
95 s->max_buf_size = s->avctx->width*s->avctx->height*s->pixel_size /* image base material */
96 + 15 /* header + footer */
97 + s->avctx->height*2 /* skip code+rle end */
98 + s->avctx->width/MAX_RLE_BULK + 1 /* rle codes */;
99 avctx->coded_frame = &s->frame;
100 return 0;
101 }
102
103 /**
104 * Computes the best RLE sequence for a line
105 */
106 static void qtrle_encode_line(QtrleEncContext *s, AVFrame *p, int line, uint8_t **buf)
107 {
108 int width=s->avctx->width;
109 int i;
110 signed char rlecode;
111
112 /* We will use it to compute the best bulk copy sequence */
113 unsigned int bulkcount;
114 /* This will be the number of pixels equal to the preivous frame one's
115 * starting from the ith pixel */
116 unsigned int skipcount;
117 /* This will be the number of consecutive equal pixels in the current
118 * frame, starting from the ith one also */
119 unsigned int av_uninit(repeatcount);
120
121 /* The cost of the three different possibilities */
122 int total_bulk_cost;
123 int total_skip_cost;
124 int total_repeat_cost;
125
126 int temp_cost;
127 int j;
128
129 uint8_t *this_line = p-> data[0] + line*p->linesize[0] + (width - 1)*s->pixel_size;
130 uint8_t *prev_line = s->previous_frame.data[0] + line*p->linesize[0] + (width - 1)*s->pixel_size;
131
132 s->length_table[width] = 0;
133 skipcount = 0;
134
135 for (i = width - 1; i >= 0; i--) {
136
137 if (!s->frame.key_frame && !memcmp(this_line, prev_line, s->pixel_size))
138 skipcount = FFMIN(skipcount + 1, MAX_RLE_SKIP);
139 else
140 skipcount = 0;
141
142 total_skip_cost = s->length_table[i + skipcount] + 2;
143 s->skip_table[i] = skipcount;
144
145
146 if (i < width - 1 && !memcmp(this_line, this_line + s->pixel_size, s->pixel_size))
147 repeatcount = FFMIN(repeatcount + 1, MAX_RLE_REPEAT);
148 else
149 repeatcount = 1;
150
151 total_repeat_cost = s->length_table[i + repeatcount] + 1 + s->pixel_size;
152
153 /* skip code is free for the first pixel, it costs one byte for repeat and bulk copy
154 * so let's make it aware */
155 if (i == 0) {
156 total_skip_cost--;
157 total_repeat_cost++;
158 }
159
160 if (repeatcount > 1 && (skipcount == 0 || total_repeat_cost < total_skip_cost)) {
161 /* repeat is the best */
162 s->length_table[i] = total_repeat_cost;
163 s->rlecode_table[i] = -repeatcount;
164 }
165 else if (skipcount > 0) {
166 /* skip is the best choice here */
167 s->length_table[i] = total_skip_cost;
168 s->rlecode_table[i] = 0;
169 }
170 else {
171 /* We cannot do neither skip nor repeat
172 * thus we search for the best bulk copy to do */
173
174 int limit = FFMIN(width - i, MAX_RLE_BULK);
175
176 temp_cost = 1 + s->pixel_size + !i;
177 total_bulk_cost = INT_MAX;
178
179 for (j = 1; j <= limit; j++) {
180 if (s->length_table[i + j] + temp_cost < total_bulk_cost) {
181 /* We have found a better bulk copy ... */
182 total_bulk_cost = s->length_table[i + j] + temp_cost;
183 bulkcount = j;
184 }
185 temp_cost += s->pixel_size;
186 }
187
188 s->length_table[i] = total_bulk_cost;
189 s->rlecode_table[i] = bulkcount;
190 }
191
192 this_line -= s->pixel_size;
193 prev_line -= s->pixel_size;
194 }
195
196 /* Good ! Now we have the best sequence for this line, let's ouput it */
197
198 /* We do a special case for the first pixel so that we avoid testing it in
199 * the whole loop */
200
201 i=0;
202 this_line = p-> data[0] + line*p->linesize[0];
203 prev_line = s->previous_frame.data[0] + line*p->linesize[0];
204
205 if (s->rlecode_table[0] == 0) {
206 bytestream_put_byte(buf, s->skip_table[0] + 1);
207 i += s->skip_table[0];
208 }
209 else bytestream_put_byte(buf, 1);
210
211
212 while (i < width) {
213 rlecode = s->rlecode_table[i];
214 bytestream_put_byte(buf, rlecode);
215 if (rlecode == 0) {
216 /* Write a skip sequence */
217 bytestream_put_byte(buf, s->skip_table[i] + 1);
218 i += s->skip_table[i];
219 }
220 else if (rlecode > 0) {
221 /* bulk copy */
222 bytestream_put_buffer(buf, this_line + i*s->pixel_size, rlecode*s->pixel_size);
223 i += rlecode;
224 }
225 else {
226 /* repeat the bits */
227 bytestream_put_buffer(buf, this_line + i*s->pixel_size, s->pixel_size);
228 i -= rlecode;
229 }
230 }
231 bytestream_put_byte(buf, -1); // end RLE line
232 }
233
234 /** Encodes frame including header */
235 static int encode_frame(QtrleEncContext *s, AVFrame *p, uint8_t *buf)
236 {
237 int i;
238 int start_line = 0;
239 int end_line = s->avctx->height;
240 uint8_t *orig_buf = buf;
241
242 if (!s->frame.key_frame) {
243 for (start_line = 0; start_line < s->avctx->height; start_line++)
244 if (memcmp(p->data[0] + start_line*p->linesize[0],
245 s->previous_frame.data[0] + start_line*p->linesize[0],
246 p->linesize[0]))
247 break;
248
249 for (end_line=s->avctx->height; end_line > start_line; end_line--)
250 if (memcmp(p->data[0] + (end_line - 1)*p->linesize[0],
251 s->previous_frame.data[0] + (end_line - 1)*p->linesize[0],
252 p->linesize[0]))
253 break;
254 }
255
256 bytestream_put_be32(&buf, 0); // CHUNK SIZE, patched later
257
258 if ((start_line == 0 && end_line == s->avctx->height) || start_line == s->avctx->height)
259 bytestream_put_be16(&buf, 0); // header
260 else {
261 bytestream_put_be16(&buf, 8); // header
262 bytestream_put_be16(&buf, start_line); // starting line
263 bytestream_put_be16(&buf, 0); // unknown
264 bytestream_put_be16(&buf, end_line - start_line); // lines to update
265 bytestream_put_be16(&buf, 0); // unknown
266 }
267 for (i = start_line; i < end_line; i++)
268 qtrle_encode_line(s, p, i, &buf);
269
270 bytestream_put_byte(&buf, 0); // zero skip code = frame finished
271 AV_WB32(orig_buf, buf - orig_buf); // patch the chunk size
272 return buf - orig_buf;
273 }
274
275 static int qtrle_encode_frame(AVCodecContext *avctx, uint8_t *buf, int buf_size, void *data)
276 {
277 QtrleEncContext * const s = avctx->priv_data;
278 AVFrame *pict = data;
279 AVFrame * const p = &s->frame;
280 int chunksize;
281
282 *p = *pict;
283
284 if (buf_size < s->max_buf_size) {
285 /* Upper bound check for compressed data */
286 av_log(avctx, AV_LOG_ERROR, "buf_size %d < %d\n", buf_size, s->max_buf_size);
287 return -1;
288 }
289
290 if (avctx->gop_size == 0 || (s->avctx->frame_number % avctx->gop_size) == 0) {
291 /* I-Frame */
292 p->pict_type = FF_I_TYPE;
293 p->key_frame = 1;
294 } else {
295 /* P-Frame */
296 p->pict_type = FF_P_TYPE;
297 p->key_frame = 0;
298 }
299
300 chunksize = encode_frame(s, pict, buf);
301
302 /* save the current frame */
303 av_picture_copy(&s->previous_frame, (AVPicture *)p, avctx->pix_fmt, avctx->width, avctx->height);
304 return chunksize;
305 }
306
307 static av_cold int qtrle_encode_end(AVCodecContext *avctx)
308 {
309 QtrleEncContext *s = avctx->priv_data;
310
311 avpicture_free(&s->previous_frame);
312 av_free(s->rlecode_table);
313 av_free(s->length_table);
314 av_free(s->skip_table);
315 return 0;
316 }
317
318 AVCodec qtrle_encoder = {
319 "qtrle",
320 CODEC_TYPE_VIDEO,
321 CODEC_ID_QTRLE,
322 sizeof(QtrleEncContext),
323 qtrle_encode_init,
324 qtrle_encode_frame,
325 qtrle_encode_end,
326 .pix_fmts = (enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_NONE},
327 .long_name = NULL_IF_CONFIG_SMALL("QuickTime Animation (RLE) video"),
328 };