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/atomic.h"

27 #include "libavutil/mem.h"

29 static AVCodecParser *av_first_parser = NULL;

31 AVCodecParser* av_parser_next(AVCodecParser *p){

32 if(p) return p->next;

33 else return av_first_parser;

34 }

36 void av_register_codec_parser(AVCodecParser *parser)

37 {

38 do {

39 parser->next = av_first_parser;

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

41 }

43 AVCodecParserContext *av_parser_init(int codec_id)

44 {

45 AVCodecParserContext *s = NULL;

46 AVCodecParser *parser;

47 int ret;

49 if(codec_id == AV_CODEC_ID_NONE)

50 return NULL;

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

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

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

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

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

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

58 goto found;

59 }

60 return NULL;

61 found:

62 s = av_mallocz(sizeof(AVCodecParserContext));

63 if (!s)

64 goto err_out;

65 s->parser = parser;

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

67 if (!s->priv_data)

68 goto err_out;

69 s->fetch_timestamp=1;

70 s->pict_type = AV_PICTURE_TYPE_I;

71 if (parser->parser_init) {

72 ret = parser->parser_init(s);

73 if (ret != 0)

74 goto err_out;

75 }

76 s->key_frame = -1;

77 s->convergence_duration = 0;

78 s->dts_sync_point = INT_MIN;

79 s->dts_ref_dts_delta = INT_MIN;

80 s->pts_dts_delta = INT_MIN;

81 return s;

83 err_out:

84 if (s)

85 av_freep(&s->priv_data);

86 av_free(s);

87 return NULL;

88 }

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

91 int i;

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

94 s->pos= -1;

95 s->offset= 0;

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

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

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

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

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

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

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

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

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

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

106 if(remove)

107 s->cur_frame_offset[i]= INT64_MAX;

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

109 break;

110 }

111 }

112 }

113

114 int av_parser_parse2(AVCodecParserContext *s,

115 AVCodecContext *avctx,

116 uint8_t **poutbuf, int *poutbuf_size,

117 const uint8_t *buf, int buf_size,

118 int64_t pts, int64_t dts,

119 int64_t pos)

120 {

121 int index, i;

122 uint8_t dummy_buf[FF_INPUT_BUFFER_PADDING_SIZE];

123

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

125 s->next_frame_offset =

126 s->cur_offset = pos;

127 s->flags |= PARSER_FLAG_FETCHED_OFFSET;

128 }

129

130 if (buf_size == 0) {

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

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

133 buf = dummy_buf;

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

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

136 /* add a new packet descriptor */

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

138 s->cur_frame_start_index = i;

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

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

141 s->cur_frame_pts[i] = pts;

142 s->cur_frame_dts[i] = dts;

143 s->cur_frame_pos[i] = pos;

144 }

145

146 if (s->fetch_timestamp){

147 s->fetch_timestamp=0;

148 s->last_pts = s->pts;

149 s->last_dts = s->dts;

150 s->last_pos = s->pos;

151 ff_fetch_timestamp(s, 0, 0);

152 }

153

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

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

156 /* update the file pointer */

157 if (*poutbuf_size) {

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

159 s->frame_offset = s->next_frame_offset;

160

161 /* offset of the next frame */

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

163 s->fetch_timestamp=1;

164 }

165 if (index < 0)

166 index = 0;

167 s->cur_offset += index;

168 return index;

169 }

170

171 int av_parser_change(AVCodecParserContext *s,

172 AVCodecContext *avctx,

173 uint8_t **poutbuf, int *poutbuf_size,

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

175

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

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

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

179 buf += i;

180 buf_size -= i;

181 }

182 }

183

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

185 *poutbuf= (uint8_t *) buf;

186 *poutbuf_size= buf_size;

187 if(avctx->extradata){

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

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

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

191 int size= buf_size + avctx->extradata_size;

192 *poutbuf_size= size;

193 *poutbuf= av_malloc(size + FF_INPUT_BUFFER_PADDING_SIZE);

194

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

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

197 return 1;

198 }

199 }

200

201 return 0;

202 }

203

204 void av_parser_close(AVCodecParserContext *s)

205 {

206 if(s){

207 if (s->parser->parser_close)

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

209 av_free(s->priv_data);

210 av_free(s);

211 }

212 }

213

214 /*****************************************************/

215

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

217 {

218 if(pc->overread){

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

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

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

222 }

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 if (next > -FF_INPUT_BUFFER_PADDING_SIZE)

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

260 next + FF_INPUT_BUFFER_PADDING_SIZE);

261 pc->index = 0;

262 *buf= pc->buffer;

263 }

264

265 /* store overread bytes */

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

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

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

269 pc->overread++;

270 }

271

272 if(pc->overread){

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

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

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

276 }

277

278 return 0;

279 }

280

281 void ff_parse_close(AVCodecParserContext *s)

282 {

283 ParseContext *pc = s->priv_data;

284

285 av_freep(&pc->buffer);

286 }

287

288 /*************************/

289

290 int ff_mpeg4video_split(AVCodecContext *avctx,

291 const uint8_t *buf, int buf_size)

292 {

293 int i;

294 uint32_t state= -1;

295

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

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

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

299 return i-3;

300 }

301 return 0;

302 }

Generated on Wed Jul 10 2013 23:48:03 for FFmpeg by doxygen 1.8.2