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path: root/libavcodec/parser.c (plain)
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1/*
2 * Audio and Video frame extraction
3 * Copyright (c) 2003 Fabrice Bellard
4 * Copyright (c) 2003 Michael Niedermayer
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include <stdint.h>
24#include <string.h>
25
26#include "libavutil/avassert.h"
27#include "libavutil/atomic.h"
28#include "libavutil/internal.h"
29#include "libavutil/mem.h"
30
31#include "internal.h"
32#include "parser.h"
33
34static AVCodecParser *av_first_parser = NULL;
35
36AVCodecParser *av_parser_next(const AVCodecParser *p)
37{
38 if (p)
39 return p->next;
40 else
41 return av_first_parser;
42}
43
44void av_register_codec_parser(AVCodecParser *parser)
45{
46 do {
47 parser->next = av_first_parser;
48 } while (parser->next != avpriv_atomic_ptr_cas((void * volatile *)&av_first_parser, parser->next, parser));
49}
50
51AVCodecParserContext *av_parser_init(int codec_id)
52{
53 AVCodecParserContext *s = NULL;
54 AVCodecParser *parser;
55 int ret;
56
57 if (codec_id == AV_CODEC_ID_NONE)
58 return NULL;
59
60 for (parser = av_first_parser; parser; parser = parser->next) {
61 if (parser->codec_ids[0] == codec_id ||
62 parser->codec_ids[1] == codec_id ||
63 parser->codec_ids[2] == codec_id ||
64 parser->codec_ids[3] == codec_id ||
65 parser->codec_ids[4] == codec_id)
66 goto found;
67 }
68 return NULL;
69
70found:
71 s = av_mallocz(sizeof(AVCodecParserContext));
72 if (!s)
73 goto err_out;
74 s->parser = parser;
75 s->priv_data = av_mallocz(parser->priv_data_size);
76 if (!s->priv_data)
77 goto err_out;
78 s->fetch_timestamp=1;
79 s->pict_type = AV_PICTURE_TYPE_I;
80 if (parser->parser_init) {
81 ret = parser->parser_init(s);
82 if (ret != 0)
83 goto err_out;
84 }
85 s->key_frame = -1;
86#if FF_API_CONVERGENCE_DURATION
87FF_DISABLE_DEPRECATION_WARNINGS
88 s->convergence_duration = 0;
89FF_ENABLE_DEPRECATION_WARNINGS
90#endif
91 s->dts_sync_point = INT_MIN;
92 s->dts_ref_dts_delta = INT_MIN;
93 s->pts_dts_delta = INT_MIN;
94 s->format = -1;
95
96 return s;
97
98err_out:
99 if (s)
100 av_freep(&s->priv_data);
101 av_free(s);
102 return NULL;
103}
104
105void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)
106{
107 int i;
108
109 if (!fuzzy) {
110 s->dts =
111 s->pts = AV_NOPTS_VALUE;
112 s->pos = -1;
113 s->offset = 0;
114 }
115 for (i = 0; i < AV_PARSER_PTS_NB; i++) {
116 if (s->cur_offset + off >= s->cur_frame_offset[i] &&
117 (s->frame_offset < s->cur_frame_offset[i] ||
118 (!s->frame_offset && !s->next_frame_offset)) && // first field/frame
119 // check disabled since MPEG-TS does not send complete PES packets
120 /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){
121
122 if (!fuzzy || s->cur_frame_dts[i] != AV_NOPTS_VALUE) {
123 s->dts = s->cur_frame_dts[i];
124 s->pts = s->cur_frame_pts[i];
125 s->pos = s->cur_frame_pos[i];
126 s->offset = s->next_frame_offset - s->cur_frame_offset[i];
127 }
128 if (remove)
129 s->cur_frame_offset[i] = INT64_MAX;
130 if (s->cur_offset + off < s->cur_frame_end[i])
131 break;
132 }
133 }
134}
135
136int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx,
137 uint8_t **poutbuf, int *poutbuf_size,
138 const uint8_t *buf, int buf_size,
139 int64_t pts, int64_t dts, int64_t pos)
140{
141 int index, i;
142 uint8_t dummy_buf[AV_INPUT_BUFFER_PADDING_SIZE];
143
144 av_assert1(avctx->codec_id != AV_CODEC_ID_NONE);
145
146 /* Parsers only work for the specified codec ids. */
147 av_assert1(avctx->codec_id == s->parser->codec_ids[0] ||
148 avctx->codec_id == s->parser->codec_ids[1] ||
149 avctx->codec_id == s->parser->codec_ids[2] ||
150 avctx->codec_id == s->parser->codec_ids[3] ||
151 avctx->codec_id == s->parser->codec_ids[4]);
152
153 if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {
154 s->next_frame_offset =
155 s->cur_offset = pos;
156 s->flags |= PARSER_FLAG_FETCHED_OFFSET;
157 }
158
159 if (buf_size == 0) {
160 /* padding is always necessary even if EOF, so we add it here */
161 memset(dummy_buf, 0, sizeof(dummy_buf));
162 buf = dummy_buf;
163 } else if (s->cur_offset + buf_size != s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */
164 /* add a new packet descriptor */
165 i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
166 s->cur_frame_start_index = i;
167 s->cur_frame_offset[i] = s->cur_offset;
168 s->cur_frame_end[i] = s->cur_offset + buf_size;
169 s->cur_frame_pts[i] = pts;
170 s->cur_frame_dts[i] = dts;
171 s->cur_frame_pos[i] = pos;
172 }
173
174 if (s->fetch_timestamp) {
175 s->fetch_timestamp = 0;
176 s->last_pts = s->pts;
177 s->last_dts = s->dts;
178 s->last_pos = s->pos;
179 ff_fetch_timestamp(s, 0, 0, 0);
180 }
181 /* WARNING: the returned index can be negative */
182 index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf,
183 poutbuf_size, buf, buf_size);
184 av_assert0(index > -0x20000000); // The API does not allow returning AVERROR codes
185#define FILL(name) if(s->name > 0 && avctx->name <= 0) avctx->name = s->name
186 if (avctx->codec_type == AVMEDIA_TYPE_VIDEO) {
187 FILL(field_order);
188 }
189
190 /* update the file pointer */
191 if (*poutbuf_size) {
192 /* fill the data for the current frame */
193 s->frame_offset = s->next_frame_offset;
194
195 /* offset of the next frame */
196 s->next_frame_offset = s->cur_offset + index;
197 s->fetch_timestamp = 1;
198 }
199 if (index < 0)
200 index = 0;
201 s->cur_offset += index;
202 return index;
203}
204
205int av_parser_change(AVCodecParserContext *s, AVCodecContext *avctx,
206 uint8_t **poutbuf, int *poutbuf_size,
207 const uint8_t *buf, int buf_size, int keyframe)
208{
209 if (s && s->parser->split) {
210 if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER ||
211 avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER) {
212 int i = s->parser->split(avctx, buf, buf_size);
213 buf += i;
214 buf_size -= i;
215 }
216 }
217
218 /* cast to avoid warning about discarding qualifiers */
219 *poutbuf = (uint8_t *) buf;
220 *poutbuf_size = buf_size;
221 if (avctx->extradata) {
222 if (keyframe && (avctx->flags2 & AV_CODEC_FLAG2_LOCAL_HEADER)) {
223 int size = buf_size + avctx->extradata_size;
224
225 *poutbuf_size = size;
226 *poutbuf = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);
227 if (!*poutbuf)
228 return AVERROR(ENOMEM);
229
230 memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
231 memcpy(*poutbuf + avctx->extradata_size, buf,
232 buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
233 return 1;
234 }
235 }
236
237 return 0;
238}
239
240void av_parser_close(AVCodecParserContext *s)
241{
242 if (s) {
243 if (s->parser->parser_close)
244 s->parser->parser_close(s);
245 av_freep(&s->priv_data);
246 av_free(s);
247 }
248}
249
250int ff_combine_frame(ParseContext *pc, int next,
251 const uint8_t **buf, int *buf_size)
252{
253 if (pc->overread) {
254 ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
255 pc->overread, pc->state, next, pc->index, pc->overread_index);
256 ff_dlog(NULL, "%X %X %X %X\n",
257 (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
258 }
259
260 /* Copy overread bytes from last frame into buffer. */
261 for (; pc->overread > 0; pc->overread--)
262 pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];
263
264 /* flush remaining if EOF */
265 if (!*buf_size && next == END_NOT_FOUND)
266 next = 0;
267
268 pc->last_index = pc->index;
269
270 /* copy into buffer end return */
271 if (next == END_NOT_FOUND) {
272 void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
273 *buf_size + pc->index +
274 AV_INPUT_BUFFER_PADDING_SIZE);
275
276 if (!new_buffer) {
277 av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", *buf_size + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
278 pc->index = 0;
279 return AVERROR(ENOMEM);
280 }
281 pc->buffer = new_buffer;
282 memcpy(&pc->buffer[pc->index], *buf, *buf_size);
283 pc->index += *buf_size;
284 return -1;
285 }
286
287 *buf_size =
288 pc->overread_index = pc->index + next;
289
290 /* append to buffer */
291 if (pc->index) {
292 void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,
293 next + pc->index +
294 AV_INPUT_BUFFER_PADDING_SIZE);
295 if (!new_buffer) {
296 av_log(NULL, AV_LOG_ERROR, "Failed to reallocate parser buffer to %d\n", next + pc->index + AV_INPUT_BUFFER_PADDING_SIZE);
297 pc->overread_index =
298 pc->index = 0;
299 return AVERROR(ENOMEM);
300 }
301 pc->buffer = new_buffer;
302 if (next > -AV_INPUT_BUFFER_PADDING_SIZE)
303 memcpy(&pc->buffer[pc->index], *buf,
304 next + AV_INPUT_BUFFER_PADDING_SIZE);
305 pc->index = 0;
306 *buf = pc->buffer;
307 }
308
309 /* store overread bytes */
310 for (; next < 0; next++) {
311 pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];
312 pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];
313 pc->overread++;
314 }
315
316 if (pc->overread) {
317 ff_dlog(NULL, "overread %d, state:%"PRIX32" next:%d index:%d o_index:%d\n",
318 pc->overread, pc->state, next, pc->index, pc->overread_index);
319 ff_dlog(NULL, "%X %X %X %X\n",
320 (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);
321 }
322
323 return 0;
324}
325
326void ff_parse_close(AVCodecParserContext *s)
327{
328 ParseContext *pc = s->priv_data;
329
330 av_freep(&pc->buffer);
331}
332
333int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)
334{
335 uint32_t state = -1;
336 const uint8_t *ptr = buf, *end = buf + buf_size;
337
338 while (ptr < end) {
339 ptr = avpriv_find_start_code(ptr, end, &state);
340 if (state == 0x1B3 || state == 0x1B6)
341 return ptr - 4 - buf;
342 }
343
344 return 0;
345}
346
generated by cgit at 2024-05-17 06:33:43 (GMT)