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127 lines
5.0 KiB
C
127 lines
5.0 KiB
C
/*
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* seek utility functions for use within 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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/**
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* structure to store parser state of one AVStream
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*/
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typedef struct AVParserStreamState {
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// saved members of AVStream
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AVCodecParserContext *parser;
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AVPacket cur_pkt;
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int64_t last_IP_pts;
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int64_t cur_dts;
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int64_t reference_dts;
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const uint8_t *cur_ptr;
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int cur_len;
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int probe_packets;
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} AVParserStreamState;
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/**
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* structure to store parser state of AVFormat
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*/
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typedef struct AVParserState {
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int64_t fpos; ///< file position at the time of call
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// saved members of AVFormatContext
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AVStream *cur_st; ///< current stream.
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AVPacketList *packet_buffer; ///< packet buffer of original state
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AVPacketList *raw_packet_buffer; ///< raw packet buffer of original state
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int raw_packet_buffer_remaining_size; ///< remaining space in raw_packet_buffer
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// saved info for streams
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int nb_streams; ///< number of streams with stored state
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AVParserStreamState *stream_states; ///< states of individual streams (array)
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} AVParserState;
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/**
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* Search for the sync point of all active streams.
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*
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* This routine 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 defined as a point in stream, such that, when decoding start
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* from this point, the decoded output of all streams synchronizes closest
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* to the given timestamp ts. This routine also takes timestamp limits into account.
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* Thus, the output will synchronize no sooner than ts_min 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 -1 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 a destructive seeking algorithm
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* to store the parser state. Depending on the outcome of the seek, either the original
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* state can be restored or the new state kept and the original state freed.
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*
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* @note As a side effect, the original parser state is reset, since structures
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* are relinked to the stored state instead of being deeply-copied (for
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* performance reasons and to keep the 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 the 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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