blob: b27cb42a9d91a34a3163d0adda2a17558d87e316
| 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 | |
| 26 | #include "avformat.h" |
| 27 | |
| 28 | /** |
| 29 | * structure to store parser state of one AVStream |
| 30 | */ |
| 31 | typedef struct AVParserStreamState { |
| 32 | // saved members of AVStream |
| 33 | AVCodecParserContext *parser; |
| 34 | int64_t last_IP_pts; |
| 35 | int64_t cur_dts; |
| 36 | int64_t reference_dts; |
| 37 | int probe_packets; |
| 38 | } AVParserStreamState; |
| 39 | |
| 40 | /** |
| 41 | * structure to store parser state of AVFormat |
| 42 | */ |
| 43 | typedef struct AVParserState { |
| 44 | int64_t fpos; ///< file position at the time of call |
| 45 | |
| 46 | // saved members of AVFormatContext |
| 47 | AVPacketList *packet_buffer; ///< packet buffer of original state |
| 48 | AVPacketList *parse_queue; ///< parse queue of original state |
| 49 | AVPacketList *raw_packet_buffer; ///< raw packet buffer of original state |
| 50 | int raw_packet_buffer_remaining_size; ///< remaining space in raw_packet_buffer |
| 51 | |
| 52 | // saved info for streams |
| 53 | int nb_streams; ///< number of streams with stored state |
| 54 | AVParserStreamState *stream_states; ///< states of individual streams (array) |
| 55 | } AVParserState; |
| 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 | */ |
| 79 | int64_t ff_gen_syncpoint_search(AVFormatContext *s, |
| 80 | int stream_index, |
| 81 | int64_t pos, |
| 82 | int64_t min_ts, |
| 83 | int64_t ts, |
| 84 | int64_t max_ts, |
| 85 | int flags); |
| 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 | */ |
| 101 | AVParserState *ff_store_parser_state(AVFormatContext *s); |
| 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 | */ |
| 113 | void ff_restore_parser_state(AVFormatContext *s, AVParserState *state); |
| 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 | */ |
| 121 | void ff_free_parser_state(AVFormatContext *s, AVParserState *state); |
| 122 | |
| 123 | #endif /* AVFORMAT_SEEK_H */ |
| 124 |