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 <string.h>

25 #include "parser.h"

26 #include "libavutil/mem.h"

28 static AVCodecParser *av_first_parser = NULL;

30 AVCodecParser* av_parser_next(AVCodecParser *p){

31 if(p) return p->next;

32 else return av_first_parser;

33 }

35 void av_register_codec_parser(AVCodecParser *parser)

36 {

37 parser->next = av_first_parser;

38 av_first_parser = parser;

39 }

41 AVCodecParserContext *av_parser_init(int codec_id)

42 {

43 AVCodecParserContext *s = NULL;

44 AVCodecParser *parser;

45 int ret;

47 if(codec_id == AV_CODEC_ID_NONE)

48 return NULL;

50 for(parser = av_first_parser; parser != NULL; parser = parser->next) {

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

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

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

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

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

56 goto found;

57 }

58 return NULL;

59 found:

60 s = av_mallocz(sizeof(AVCodecParserContext));

61 if (!s)

62 goto err_out;

63 s->parser = parser;

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

65 if (!s->priv_data)

66 goto err_out;

67 s->fetch_timestamp=1;

68 s->pict_type = AV_PICTURE_TYPE_I;

69 if (parser->parser_init) {

70 ret = parser->parser_init(s);

71 if (ret != 0)

72 goto err_out;

73 }

74 s->key_frame = -1;

75 s->convergence_duration = 0;

76 s->dts_sync_point = INT_MIN;

77 s->dts_ref_dts_delta = INT_MIN;

78 s->pts_dts_delta = INT_MIN;

79 return s;

81 err_out:

82 if (s)

83 av_freep(&s->priv_data);

84 av_free(s);

85 return NULL;

86 }

88 void ff_fetch_timestamp(AVCodecParserContext *s, int off, int remove){

89 int i;

91 s->dts= s->pts= AV_NOPTS_VALUE;

92 s->pos= -1;

93 s->offset= 0;

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

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

96 && (s->frame_offset < s->cur_frame_offset[i] ||

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

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

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

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

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

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

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

104 if(remove)

105 s->cur_frame_offset[i]= INT64_MAX;

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

107 break;

108 }

109 }

110 }

111

112 int av_parser_parse2(AVCodecParserContext *s,

113 AVCodecContext *avctx,

114 uint8_t **poutbuf, int *poutbuf_size,

115 const uint8_t *buf, int buf_size,

116 int64_t pts, int64_t dts,

117 int64_t pos)

118 {

119 int index, i;

120 uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];

121

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

123 s->next_frame_offset =

124 s->cur_offset = pos;

125 s->flags |= PARSER_FLAG_FETCHED_OFFSET;

126 }

127

128 if (buf_size == 0) {

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

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

131 buf = dummy_buf;

132 } else if (s->cur_offset + buf_size !=

133 s->cur_frame_end[s->cur_frame_start_index]) { /* skip remainder packets */

134 /* add a new packet descriptor */

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

136 s->cur_frame_start_index = i;

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

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

139 s->cur_frame_pts[i] = pts;

140 s->cur_frame_dts[i] = dts;

141 s->cur_frame_pos[i] = pos;

142 }

143

144 if (s->fetch_timestamp){

145 s->fetch_timestamp=0;

146 s->last_pts = s->pts;

147 s->last_dts = s->dts;

148 s->last_pos = s->pos;

149 ff_fetch_timestamp(s, 0, 0);

150 }

151

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

153 index = s->parser->parser_parse(s, avctx, (const uint8_t **)poutbuf, poutbuf_size, buf, buf_size);

154 /* update the file pointer */

155 if (*poutbuf_size) {

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

157 s->frame_offset = s->next_frame_offset;

158

159 /* offset of the next frame */

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

161 s->fetch_timestamp=1;

162 }

163 if (index < 0)

164 index = 0;

165 s->cur_offset += index;

166 return index;

167 }

168

169 int av_parser_change(AVCodecParserContext *s,

170 AVCodecContext *avctx,

171 uint8_t **poutbuf, int *poutbuf_size,

172 const uint8_t *buf, int buf_size, int keyframe){

173

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

175 if((avctx->flags & CODEC_FLAG_GLOBAL_HEADER) || (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER)){

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

177 buf += i;

178 buf_size -= i;

179 }

180 }

181

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

183 *poutbuf= (uint8_t *) buf;

184 *poutbuf_size= buf_size;

185 if(avctx->extradata){

186 if( (keyframe && (avctx->flags2 & CODEC_FLAG2_LOCAL_HEADER))

187 /*||(s->pict_type != AV_PICTURE_TYPE_I && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_NOKEY))*/

188 /*||(? && (s->flags & PARSER_FLAG_DUMP_EXTRADATA_AT_BEGIN)*/){

189 int size= buf_size + avctx->extradata_size;

190 *poutbuf_size= size;

191 *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);

192

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

194 memcpy((*poutbuf) + avctx->extradata_size, buf, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);

195 return 1;

196 }

197 }

198

199 return 0;

200 }

201

202 void av_parser_close(AVCodecParserContext *s)

203 {

204 if(s){

205 if (s->parser->parser_close)

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

207 av_free(s->priv_data);

208 av_free(s);

209 }

210 }

211

212 /*****************************************************/

213

214 int ff_combine_frame(ParseContext *pc, int next, const uint8_t **buf, int *buf_size)

215 {

216 if(pc->overread){

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

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

219 av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1], (*buf)[2], (*buf)[3]);

220 }

221

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

223 for(; pc->overread>0; pc->overread--){

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

225 }

226

227 /* flush remaining if EOF */

228 if(!*buf_size && next == END_NOT_FOUND){

229 next= 0;

230 }

231

232 pc->last_index= pc->index;

233

234 /* copy into buffer end return */

235 if(next == END_NOT_FOUND){

236 void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, (*buf_size) + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);

237

238 if(!new_buffer)

239 return AVERROR(ENOMEM);

240 pc->buffer = new_buffer;

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

242 pc->index += *buf_size;

243 return -1;

244 }

245

246 *buf_size=

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

248

249 /* append to buffer */

250 if(pc->index){

251 void* new_buffer = av_fast_realloc(pc->buffer, &pc->buffer_size, next + pc->index + FF_INPUT_BUFFER_PADDING_SIZE);

252

253 if(!new_buffer)

254 return AVERROR(ENOMEM);

255 pc->buffer = new_buffer;

256 if (next > -FF_INPUT_BUFFER_PADDING_SIZE)

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

258 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->state64 = (pc->state64<<8) | pc->buffer[pc->last_index + next];

267 pc->overread++;

268 }

269

270 if(pc->overread){

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

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

273 av_dlog(NULL, "%X %X %X %X\n", (*buf)[0], (*buf)[1],(*buf)[2],(*buf)[3]);

274 }

275

276 return 0;

277 }

278

279 void ff_parse_close(AVCodecParserContext *s)

280 {

281 ParseContext *pc = s->priv_data;

282

283 av_freep(&pc->buffer);

284 }

285

286 /*************************/

287

288 int ff_mpeg4video_split(AVCodecContext *avctx,

289 const uint8_t *buf, int buf_size)

290 {

291 int i;

292 uint32_t state= -1;

293

294 for(i=0; i<buf_size; i++){

295 state= (state<<8) | buf[i];

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

297 return i-3;

298 }

299 return 0;

300 }

Generated on Sat May 25 2013 03:58:39 for FFmpeg by doxygen 1.8.2