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/*
* Utility functions for seeking for use within FFmpeg 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"
/// Opaque structure for parser state.
typedef struct AVParserState AVParserState;
/**
* Search for sync point of all active streams.
*
* This is not supposed to be called directly by a user application,
* but by demuxers.
*
* A sync point is a point in stream, so that decoding from this point,
* output of decoders of all streams synchronizes closest to given timestamp
* ts (but taking timestamp limits into account, i.e., 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 < 0 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 destructive seeking algorithm
* to store parser state. After the seek, depending on outcome, original state
* can be restored or new state kept and original state freed.
*
* @note As a side effect, original parser state is reset, since structures
* are relinked to stored state instead of being deeply-copied (for
* performance reasons and to keep 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 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 */
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