0,0 → 1,123 |
/* |
* seek utility functions for use within format handlers |
* |
* Copyright (c) 2009 Ivan Schreter |
* |
* This file is part of FFmpeg. |
* |
* FFmpeg is free software; you can redistribute it and/or |
* modify it under the terms of the GNU Lesser General Public |
* License as published by the Free Software Foundation; either |
* version 2.1 of the License, or (at your option) any later version. |
* |
* FFmpeg is distributed in the hope that it will be useful, |
* but WITHOUT ANY WARRANTY; without even the implied warranty of |
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
* Lesser General Public License for more details. |
* |
* You should have received a copy of the GNU Lesser General Public |
* License along with FFmpeg; if not, write to the Free Software |
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
*/ |
|
#ifndef AVFORMAT_SEEK_H |
#define AVFORMAT_SEEK_H |
|
#include "avformat.h" |
|
/** |
* structure to store parser state of one AVStream |
*/ |
typedef struct AVParserStreamState { |
// saved members of AVStream |
AVCodecParserContext *parser; |
int64_t last_IP_pts; |
int64_t cur_dts; |
int64_t reference_dts; |
int probe_packets; |
} AVParserStreamState; |
|
/** |
* structure to store parser state of AVFormat |
*/ |
typedef struct AVParserState { |
int64_t fpos; ///< file position at the time of call |
|
// saved members of AVFormatContext |
AVPacketList *packet_buffer; ///< packet buffer of original state |
AVPacketList *parse_queue; ///< parse queue of original state |
AVPacketList *raw_packet_buffer; ///< raw packet buffer of original state |
int raw_packet_buffer_remaining_size; ///< remaining space in raw_packet_buffer |
|
// saved info for streams |
int nb_streams; ///< number of streams with stored state |
AVParserStreamState *stream_states; ///< states of individual streams (array) |
} AVParserState; |
|
/** |
* Search for the sync point of all active streams. |
* |
* This routine is not supposed to be called directly by a user application, |
* but by demuxers. |
* |
* A sync point is defined as a point in stream, such that, when decoding start |
* from this point, the decoded output of all streams synchronizes closest |
* to the given timestamp ts. This routine also takes timestamp limits into account. |
* Thus, the output will synchronize no sooner than ts_min and no later than ts_max. |
* |
* @param stream_index stream index for time base reference of timestamps |
* @param pos approximate position where to start searching for key frames |
* @param min_ts minimum allowed timestamp (position, if AVSEEK_FLAG_BYTE set) |
* @param ts target timestamp (or position, if AVSEEK_FLAG_BYTE set in flags) |
* @param max_ts maximum allowed timestamp (position, if AVSEEK_FLAG_BYTE set) |
* @param flags if AVSEEK_FLAG_ANY is set, seek to any frame, otherwise only |
* to a keyframe. If AVSEEK_FLAG_BYTE is set, search by |
* position, not by timestamp. |
* @return -1 if no such sync point could be found, otherwise stream position |
* (stream is repositioned to this position) |
*/ |
int64_t ff_gen_syncpoint_search(AVFormatContext *s, |
int stream_index, |
int64_t pos, |
int64_t min_ts, |
int64_t ts, |
int64_t max_ts, |
int flags); |
|
/** |
* Store current parser state and file position. |
* |
* This function can be used by demuxers before a destructive seeking algorithm |
* to store the parser state. Depending on the outcome of the seek, either the original |
* state can be restored or the new state kept and the original state freed. |
* |
* @note As a side effect, the original parser state is reset, since structures |
* are relinked to the stored state instead of being deeply-copied (for |
* performance reasons and to keep the code simple). |
* |
* @param s context from which to save state |
* @return parser state object or NULL if memory could not be allocated |
*/ |
AVParserState *ff_store_parser_state(AVFormatContext *s); |
|
/** |
* Restore previously saved parser state and file position. |
* |
* Saved state will be invalidated and freed by this call, since internal |
* structures will be relinked back to the stored state instead of being |
* deeply-copied. |
* |
* @param s context to which to restore state (same as used for storing state) |
* @param state state to restore |
*/ |
void ff_restore_parser_state(AVFormatContext *s, AVParserState *state); |
|
/** |
* Free previously saved parser state. |
* |
* @param s context to which the state belongs (same as used for storing state) |
* @param state state to free |
*/ |
void ff_free_parser_state(AVFormatContext *s, AVParserState *state); |
|
#endif /* AVFORMAT_SEEK_H */ |