FFmpeg: libavcodec/parser.c Source File

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libavcodec

parser.c

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1 /*

2 * Audio and Video frame extraction

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 */

23 #include <stdint.h>

24 #include <string.h>

26 #include "libavutil/avassert.h"

27 #include "libavutil/atomic.h"

28 #include "libavutil/mem.h"

30 #include "parser.h"

31 #include "internal.h"

33 static AVCodecParser *av_first_parser = NULL;

35 AVCodecParser *av_parser_next(const AVCodecParser *p)

36 {

37 if (p)

38 return p->next;

39 else

40 return av_first_parser;

41 }

43 void av_register_codec_parser(AVCodecParser *parser)

44 {

45 do {

46 parser->next = av_first_parser;

47 } while (parser->next != avpriv_atomic_ptr_cas((void * volatile *)&av_first_parser, parser->next, parser));

48 }

50 AVCodecParserContext *av_parser_init(int codec_id)

51 {

52 AVCodecParserContext *s = NULL;

53 AVCodecParser *parser;

54 int ret;

56 if (codec_id == AV_CODEC_ID_NONE)

57 return NULL;

59 for (parser = av_first_parser; parser; parser = parser->next) {

60 if (parser->codec_ids[0] == codec_id ||

61 parser->codec_ids[1] == codec_id ||

62 parser->codec_ids[2] == codec_id ||

63 parser->codec_ids[3] == codec_id ||

64 parser->codec_ids[4] == codec_id)

65 goto found;

66 }

67 return NULL;

69 found:

70 s = av_mallocz(sizeof(AVCodecParserContext));

71 if (!s)

72 goto err_out;

73 s->parser = parser;

74 s->priv_data = av_mallocz(parser->priv_data_size);

75 if (!s->priv_data)

76 goto err_out;

77 s->fetch_timestamp=1;

78 s->pict_type = AV_PICTURE_TYPE_I;

79 if (parser->parser_init) {

80 ret = parser->parser_init(s);

81 if (ret != 0)

82 goto err_out;

83 }

84 s->key_frame = -1;

85 s->convergence_duration = 0;

86 s->dts_sync_point = INT_MIN;

87 s->dts_ref_dts_delta = INT_MIN;

88 s->pts_dts_delta = INT_MIN;

89 s->format = -1;

91 return s;

93 err_out:

94 if (s)

95 av_freep(&s->priv_data);

96 av_free(s);

97 return NULL;

98 }

100 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove, int fuzzy)

101 {

102 int i;

103

104 if (!fuzzy) {

105 s->dts =

106 s->pts = AV_NOPTS_VALUE;

107 s->pos = -1;

108 s->offset = 0;

109 }

110 for (i = 0; i < AV_PARSER_PTS_NB; i++) {

111 if (s->cur_offset + off >= s->cur_frame_offset[i] &&

112 (s->frame_offset < s->cur_frame_offset[i] ||

113 (!s->frame_offset && !s->next_frame_offset)) && // first field/frame

114 // check disabled since MPEG-TS does not send complete PES packets

115 /*s->next_frame_offset + off <*/ s->cur_frame_end[i]){

116

117 if (!fuzzy || s->cur_frame_dts[i] != AV_NOPTS_VALUE) {

118 s->dts = s->cur_frame_dts[i];

119 s->pts = s->cur_frame_pts[i];

120 s->pos = s->cur_frame_pos[i];

121 s->offset = s->next_frame_offset - s->cur_frame_offset[i];

122 }

123 if (remove)

124 s->cur_frame_offset[i] = INT64_MAX;

125 if (s->cur_offset + off < s->cur_frame_end[i])

126 break;

127 }

128 }

129 }

130

131 int av_parser_parse2(AVCodecParserContext *s, AVCodecContext *avctx,

132 uint8_t **poutbuf, int *poutbuf_size,

133 const uint8_t *buf, int buf_size,

134 int64_t pts, int64_t dts, int64_t pos)

135 {

136 int index, i;

137 uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];

138

139 if (!(s->flags & PARSER_FLAG_FETCHED_OFFSET)) {

140 s->next_frame_offset =

141 s->cur_offset = pos;

142 s->flags |= PARSER_FLAG_FETCHED_OFFSET;

143 }

144

145 if (buf_size == 0) {

146 /* padding is always necessary even if EOF, so we add it here */

147 memset(dummy_buf, 0, sizeof(dummy_buf));

148 buf = dummy_buf;

149 } else if (s->cur_offset + buf_size != s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */

150 /* add a new packet descriptor */

151 i = (s->cur_frame_start_index + 1) & (AV_PARSER_PTS_NB - 1);

152 s->cur_frame_start_index = i;

153 s->cur_frame_offset[i] = s->cur_offset;

154 s->cur_frame_end[i] = s->cur_offset + buf_size;

155 s->cur_frame_pts[i] = pts;

156 s->cur_frame_dts[i] = dts;

157 s->cur_frame_pos[i] = pos;

158 }

159

160 if (s->fetch_timestamp) {

161 s->fetch_timestamp = 0;

162 s->last_pts = s->pts;

163 s->last_dts = s->dts;

164 s->last_pos = s->pos;

165 ff_fetch_timestamp(s, 0, 0, 0);

166 }

167 /* WARNING: the returned index can be negative */

168 index = s->parser->parser_parse(s, avctx, (const uint8_t **) poutbuf,

169 poutbuf_size, buf, buf_size);

170 av_assert0(index > -0x20000000); // The API does not allow returning AVERROR codes

171 /* update the file pointer */

172 if (*poutbuf_size) {

173 /* fill the data for the current frame */

174 s->frame_offset = s->next_frame_offset;

175

176 /* offset of the next frame */

177 s->next_frame_offset = s->cur_offset + index;

178 s->fetch_timestamp = 1;

179 }

180 if (index < 0)

181 index = 0;

182 s->cur_offset += index;

183 return index;

184 }

185

186 int av_parser_change(AVCodecParserContext *s, AVCodecContext *avctx,

187 uint8_t **poutbuf, int *poutbuf_size,

188 const uint8_t *buf, int buf_size, int keyframe)

189 {

190 if (s && s->parser->split) {

191 if (avctx->flags & CODEC_FLAG_GLOBAL_HEADER ||

192 avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER) {

193 int i = s->parser->split(avctx, buf, buf_size);

194 buf += i;

195 buf_size -= i;

196 }

197 }

198

199 /* cast to avoid warning about discarding qualifiers */

200 *poutbuf = (uint8_t *) buf;

201 *poutbuf_size = buf_size;

202 if (avctx->extradata) {

203 if (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)) {

204 int size = buf_size + avctx->extradata_size;

205

206 *poutbuf_size = size;

207 *poutbuf = av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);

208 if (!*poutbuf)

209 return AVERROR(ENOMEM);

210

211 memcpy(*poutbuf, avctx->extradata, avctx->extradata_size);

212 memcpy(*poutbuf + avctx->extradata_size, buf,

213 buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

214 return 1;

215 }

216 }

217

218 return 0;

219 }

220

221 void av_parser_close(AVCodecParserContext *s)

222 {

223 if (s) {

224 if (s->parser->parser_close)

225 s->parser->parser_close(s);

226 av_freep(&s->priv_data);

227 av_free(s);

228 }

229 }

230

231 int ff_combine_frame(ParseContext *pc, int next,

232 const uint8_t **buf, int *buf_size)

233 {

234 if (pc->overread) {

235 av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",

236 pc->overread, pc->state, next, pc->index, pc->overread_index);

237 av_dlog(NULL, "%X %X %X %X\n",

238 (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);

239 }

240

241 /* Copy overread bytes from last frame into buffer. */

242 for (; pc->overread > 0; pc->overread--)

243 pc->buffer[pc->index++] = pc->buffer[pc->overread_index++];

244

245 /* flush remaining if EOF */

246 if (!*buf_size && next == END_NOT_FOUND)

247 next = 0;

248

249 pc->last_index = pc->index;

250

251 /* copy into buffer end return */

252 if (next == END_NOT_FOUND) {

253 void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,

254 *buf_size + pc->index +

255 FF_INPUT_BUFFER_PADDING_SIZE);

256

257 if (!new_buffer) {

258 pc->index = 0;

259 return AVERROR(ENOMEM);

260 }

261 pc->buffer = new_buffer;

262 memcpy(&pc->buffer[pc->index], *buf, *buf_size);

263 pc->index += *buf_size;

264 return -1;

265 }

266

267 *buf_size =

268 pc->overread_index = pc->index + next;

269

270 /* append to buffer */

271 if (pc->index) {

272 void *new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size,

273 next + pc->index +

274 FF_INPUT_BUFFER_PADDING_SIZE);

275 if (!new_buffer) {

276 pc->overread_index =

277 pc->index = 0;

278 return AVERROR(ENOMEM);

279 }

280 pc->buffer = new_buffer;

281 if (next > -FF_INPUT_BUFFER_PADDING_SIZE)

282 memcpy(&pc->buffer[pc->index], *buf,

283 next + FF_INPUT_BUFFER_PADDING_SIZE);

284 pc->index = 0;

285 *buf = pc->buffer;

286 }

287

288 /* store overread bytes */

289 for (; next < 0; next++) {

290 pc->state = pc->state << 8 | pc->buffer[pc->last_index + next];

291 pc->state64 = pc->state64 << 8 | pc->buffer[pc->last_index + next];

292 pc->overread++;

293 }

294

295 if (pc->overread) {

296 av_dlog(NULL, "overread %d, state:%X next:%d index:%d o_index:%d\n",

297 pc->overread, pc->state, next, pc->index, pc->overread_index);

298 av_dlog(NULL, "%X %X %X %X\n",

299 (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);

300 }

301

302 return 0;

303 }

304

305 void ff_parse_close(AVCodecParserContext *s)

306 {

307 ParseContext *pc = s->priv_data;

308

309 av_freep(&pc->buffer);

310 }

311

312 int ff_mpeg4video_split(AVCodecContext *avctx, const uint8_t *buf, int buf_size)

313 {

314 uint32_t state = -1;

315 const uint8_t *ptr = buf, *end = buf + buf_size;

316

317 while (ptr < end) {

318 ptr = avpriv_find_start_code(ptr, end, &state);

319 if (state == 0x1B3 || state == 0x1B6)

320 return ptr - 4 - buf;

321 }

322

323 return 0;

324 }

Generated on Sun Mar 8 2015 02:34:58 for FFmpeg by doxygen 1.8.2