00356b10e5668c1fff3fd4ce29b17076f29d7153
[libav.git] / libavcodec / parser.c
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 "parser.h"
24
25 AVCodecParser *av_first_parser = NULL;
26
27 AVCodecParser* av_parser_next(AVCodecParser *p){
28 if(p) return p->next;
29 else return av_first_parser;
30 }
31
32 void av_register_codec_parser(AVCodecParser *parser)
33 {
34 parser->next = av_first_parser;
35 av_first_parser = parser;
36 }
37
38 AVCodecParserContext *av_parser_init(int codec_id)
39 {
40 AVCodecParserContext *s;
41 AVCodecParser *parser;
42 int ret;
43
44 if(codec_id == CODEC_ID_NONE)
45 return NULL;
46
47 for(parser = av_first_parser; parser != NULL; parser = parser->next) {
48 if (parser->codec_ids[0] == codec_id ||
49 parser->codec_ids[1] == codec_id ||
50 parser->codec_ids[2] == codec_id ||
51 parser->codec_ids[3] == codec_id ||
52 parser->codec_ids[4] == codec_id)
53 goto found;
54 }
55 return NULL;
56 found:
57 s = av_mallocz(sizeof(AVCodecParserContext));
58 if (!s)
59 return NULL;
60 s->parser = parser;
61 s->priv_data = av_mallocz(parser->priv_data_size);
62 if (!s->priv_data) {
63 av_free(s);
64 return NULL;
65 }
66 if (parser->parser_init) {
67 ret = parser->parser_init(s);
68 if (ret != 0) {
69 av_free(s->priv_data);
70 av_free(s);
71 return NULL;
72 }
73 }
74 s->fetch_timestamp=1;
75 s->pict_type = FF_I_TYPE;
76 return s;
77 }
78
79 /**
80 *
81 * @param buf input
82 * @param buf_size input length, to signal EOF, this should be 0 (so that the last frame can be output)
83 * @param pts input presentation timestamp
84 * @param dts input decoding timestamp
85 * @param poutbuf will contain a pointer to the first byte of the output frame
86 * @param poutbuf_size will contain the length of the output frame
87 * @return the number of bytes of the input bitstream used
88 *
89 * Example:
90 * @code
91 * while(in_len){
92 * len = av_parser_parse(myparser, AVCodecContext, &data, &size,
93 * in_data, in_len,
94 * pts, dts);
95 * in_data += len;
96 * in_len -= len;
97 *
98 * if(size)
99 * decode_frame(data, size);
100 * }
101 * @endcode
102 */
103 int av_parser_parse(AVCodecParserContext *s,
104 AVCodecContext *avctx,
105 uint8_t **poutbuf, int *poutbuf_size,
106 const uint8_t *buf, int buf_size,
107 int64_t pts, int64_t dts)
108 {
109 int index, i, k;
110 uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];
111
112 if (buf_size == 0) {
113 /* padding is always necessary even if EOF, so we add it here */
114 memset(dummy_buf, 0, sizeof(dummy_buf));
115 buf = dummy_buf;
116 } else {
117 /* add a new packet descriptor */
118 k = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);
119 s->cur_frame_start_index = k;
120 s->cur_frame_offset[k] = s->cur_offset;
121 s->cur_frame_end[k] = s->cur_offset + buf_size;
122 s->cur_frame_pts[k] = pts;
123 s->cur_frame_dts[k] = dts;
124 }
125
126 if (s->fetch_timestamp){
127 s->fetch_timestamp=0;
128 s->last_pts = s->pts;
129 s->last_dts = s->dts;
130 s->dts= s->pts= AV_NOPTS_VALUE;
131 s->offset= 0;
132 for(i = 0; i < AV_PARSER_PTS_NB; i++) {
133 if ( s->next_frame_offset >= s->cur_frame_offset[i]
134 &&(s-> frame_offset < s->cur_frame_offset[i] || !s->frame_offset)
135 && s->next_frame_offset < s->cur_frame_end[i]){
136 s->dts= s->cur_frame_dts[i];
137 s->pts= s->cur_frame_pts[i];
138 s->offset = s->next_frame_offset - s->cur_frame_offset[i];
139 }
140 }
141 }
142
143 /* WARNING: the returned index can be negative */
144 index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);
145 //av_log(NULL, AV_LOG_DEBUG, "parser: in:%"PRId64", %"PRId64", out:%"PRId64", %"PRId64", in:%d out:%d id:%d\n", pts, dts, s->last_pts, s->last_dts, buf_size, *poutbuf_size, avctx->codec_id);
146 /* update the file pointer */
147 if (*poutbuf_size) {
148 /* fill the data for the current frame */
149 s->frame_offset = s->next_frame_offset;
150
151 /* offset of the next frame */
152 s->next_frame_offset = s->cur_offset + index;
153 s->fetch_timestamp=1;
154 }
155 if (index < 0)
156 index = 0;
157 s->cur_offset += index;
158 return index;
159 }
160
161 /**
162 *
163 * @return 0 if the output buffer is a subset of the input, 1 if it is allocated and must be freed
164 * @deprecated use AVBitstreamFilter
165 */
166 int av_parser_change(AVCodecParserContext *s,
167 AVCodecContext *avctx,
168 uint8_t **poutbuf, int *poutbuf_size,
169 const uint8_t *buf, int buf_size, int keyframe){
170
171 if(s && s->parser->split){
172 if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){
173 int i= s->parser->split(avctx, buf, buf_size);
174 buf += i;
175 buf_size -= i;
176 }
177 }
178
179 /* cast to avoid warning about discarding qualifiers */
180 *poutbuf= (uint8_t *) buf;
181 *poutbuf_size= buf_size;
182 if(avctx->extradata){
183 if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))
184 /*||(s->pict_type != FF_I_TYPE && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/
185 /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){
186 int size= buf_size + avctx->extradata_size;
187 *poutbuf_size= size;
188 *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);
189
190 memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);
191 memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
192 return 1;
193 }
194 }
195
196 return 0;
197 }
198
199 void av_parser_close(AVCodecParserContext *s)
200 {
201 if(s){
202 if (s->parser->parser_close)
203 s->parser->parser_close(s);
204 av_free(s->priv_data);
205 av_free(s);
206 }
207 }
208
209 /*****************************************************/
210
211 /**
212 * combines the (truncated) bitstream to a complete frame
213 * @returns -1 if no complete frame could be created, AVERROR(ENOMEM) if there was a memory allocation error
214 */
215 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)
216 {
217 #if 0
218 if(pc->overread){
219 printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
220 printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
221 }
222 #endif
223
224 /* Copy overread bytes from last frame into buffer. */
225 for(; pc->overread>0; pc->overread--){
226 pc->buffer[pc->index++]= pc->buffer[pc->overread_index++];
227 }
228
229 /* flush remaining if EOF */
230 if(!*buf_size && next == END_NOT_FOUND){
231 next= 0;
232 }
233
234 pc->last_index= pc->index;
235
236 /* copy into buffer end return */
237 if(next == END_NOT_FOUND){
238 void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
239
240 if(!new_buffer)
241 return AVERROR(ENOMEM);
242 pc->buffer = new_buffer;
243 memcpy(&pc->buffer[pc->index], *buf, *buf_size);
244 pc->index += *buf_size;
245 return -1;
246 }
247
248 *buf_size=
249 pc->overread_index= pc->index + next;
250
251 /* append to buffer */
252 if(pc->index){
253 void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);
254
255 if(!new_buffer)
256 return AVERROR(ENOMEM);
257 pc->buffer = new_buffer;
258 memcpy(&pc->buffer[pc->index], *buf, next + FF_INPUT_BUFFER_PADDING_SIZE );
259 pc->index = 0;
260 *buf= pc->buffer;
261 }
262
263 /* store overread bytes */
264 for(;next < 0; next++){
265 pc->state = (pc->state<<8) | pc->buffer[pc->last_index + next];
266 pc->overread++;
267 }
268
269 #if 0
270 if(pc->overread){
271 printf("overread %d, state:%X next:%d index:%d o_index:%d\n", pc->overread, pc->state, next, pc->index, pc->overread_index);
272 printf("%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);
273 }
274 #endif
275
276 return 0;
277 }
278
279 void ff_parse_close(AVCodecParserContext *s)
280 {
281 ParseContext *pc = s->priv_data;
282
283 av_free(pc->buffer);
284 }
285
286 void ff_parse1_close(AVCodecParserContext *s)
287 {
288 ParseContext1 *pc1 = s->priv_data;
289
290 av_free(pc1->pc.buffer);
291 av_free(pc1->enc);
292 }
293
294 /*************************/
295
296 int ff_mpeg4video_split(AVCodecContext *avctx,
297 const uint8_t *buf, int buf_size)
298 {
299 int i;
300 uint32_t state= -1;
301
302 for(i=0; i<buf_size; i++){
303 state= (state<<8) | buf[i];
304 if(state == 0x1B3 || state == 0x1B6)
305 return i-3;
306 }
307 return 0;
308 }