1 /*
2 * seek utility functions for use within format handlers
3 *
4 * Copyright (c) 2009 Ivan Schreter
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 */
22
23 #ifndef AVFORMAT_SEEK_H
24 #define AVFORMAT_SEEK_H
25
27
28 /**
29 * structure to store parser state of one AVStream
30 */
32 // saved members of AVStream
39
40 /**
41 * structure to store parser state of AVFormat
42 */
44 int64_t
fpos;
///< file position at the time of call
45
46 // saved members of AVFormatContext
51
52 // saved info for streams
56
57 /**
58 * Search for the sync point of all active streams.
59 *
60 * This routine is not supposed to be called directly by a user application,
61 * but by demuxers.
62 *
63 * A sync point is defined as a point in stream, such that, when decoding start
64 * from this point, the decoded output of all streams synchronizes closest
65 * to the given timestamp ts. This routine also takes timestamp limits into account.
66 * Thus, the output will synchronize no sooner than ts_min and no later than ts_max.
67 *
68 * @param stream_index stream index for time base reference of timestamps
69 * @param pos approximate position where to start searching for key frames
70 * @param min_ts minimum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
71 * @param ts target timestamp (or position, if AVSEEK_FLAG_BYTE set in flags)
72 * @param max_ts maximum allowed timestamp (position, if AVSEEK_FLAG_BYTE set)
73 * @param flags if AVSEEK_FLAG_ANY is set, seek to any frame, otherwise only
74 * to a keyframe. If AVSEEK_FLAG_BYTE is set, search by
75 * position, not by timestamp.
76 * @return -1 if no such sync point could be found, otherwise stream position
77 * (stream is repositioned to this position)
78 */
80 int stream_index,
81 int64_t pos,
82 int64_t min_ts,
83 int64_t ts,
84 int64_t max_ts,
86
87 /**
88 * Store current parser state and file position.
89 *
90 * This function can be used by demuxers before a destructive seeking algorithm
91 * to store the parser state. Depending on the outcome of the seek, either the original
92 * state can be restored or the new state kept and the original state freed.
93 *
94 * @note As a side effect, the original parser state is reset, since structures
95 * are relinked to the stored state instead of being deeply-copied (for
96 * performance reasons and to keep the code simple).
97 *
98 * @param s context from which to save state
99 * @return parser state object or NULL if memory could not be allocated
100 */
102
103 /**
104 * Restore previously saved parser state and file position.
105 *
106 * Saved state will be invalidated and freed by this call, since internal
107 * structures will be relinked back to the stored state instead of being
108 * deeply-copied.
109 *
110 * @param s context to which to restore state (same as used for storing state)
111 * @param state state to restore
112 */
114
115 /**
116 * Free previously saved parser state.
117 *
118 * @param s context to which the state belongs (same as used for storing state)
119 * @param state state to free
120 */
122
123 #endif /* AVFORMAT_SEEK_H */