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