[go: nahoru, domu]
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef A_TS_PARSER_H_
18
19#define A_TS_PARSER_H_
20
21#include <sys/types.h>
22
23#include <media/stagefright/foundation/ABase.h>
24#include <media/stagefright/foundation/AMessage.h>
25#include <media/stagefright/MediaSource.h>
26#include <utils/KeyedVector.h>
27#include <utils/Vector.h>
28#include <utils/RefBase.h>
29
30namespace android {
31
32class ABitReader;
33struct ABuffer;
34
35struct ATSParser : public RefBase {
36    enum DiscontinuityType {
37        DISCONTINUITY_NONE              = 0,
38        DISCONTINUITY_TIME              = 1,
39        DISCONTINUITY_AUDIO_FORMAT      = 2,
40        DISCONTINUITY_VIDEO_FORMAT      = 4,
41        DISCONTINUITY_ABSOLUTE_TIME     = 8,
42        DISCONTINUITY_TIME_OFFSET       = 16,
43
44        // For legacy reasons this also implies a time discontinuity.
45        DISCONTINUITY_FORMATCHANGE      =
46            DISCONTINUITY_AUDIO_FORMAT
47                | DISCONTINUITY_VIDEO_FORMAT
48                | DISCONTINUITY_TIME,
49        DISCONTINUITY_FORMAT_ONLY       =
50            DISCONTINUITY_AUDIO_FORMAT
51                | DISCONTINUITY_VIDEO_FORMAT,
52    };
53
54    enum Flags {
55        // The 90kHz clock (PTS/DTS) is absolute, i.e. PTS=0 corresponds to
56        // a media time of 0.
57        // If this flag is _not_ specified, the first PTS encountered in a
58        // program of this stream will be assumed to correspond to media time 0
59        // instead.
60        TS_TIMESTAMPS_ARE_ABSOLUTE = 1,
61        // Video PES packets contain exactly one (aligned) access unit.
62        ALIGNED_VIDEO_DATA         = 2,
63    };
64
65    // Event is used to signal sync point event at feedTSPacket().
66    struct SyncEvent {
67        SyncEvent(off64_t offset);
68
69        void init(off64_t offset, const sp<MediaSource> &source,
70                int64_t timeUs);
71
72        bool hasReturnedData() const { return mHasReturnedData; }
73        void reset();
74        off64_t getOffset() const { return mOffset; }
75        const sp<MediaSource> &getMediaSource() const { return mMediaSource; }
76        int64_t getTimeUs() const { return mTimeUs; }
77
78    private:
79        bool mHasReturnedData;
80        /*
81         * mHasReturnedData == false: the current offset (or undefined if the returned data
82                                      has been invalidated via reset())
83         * mHasReturnedData == true: the start offset of sync payload
84         */
85        off64_t mOffset;
86        /* The media source object for this event. */
87        sp<MediaSource> mMediaSource;
88        /* The timestamp of the sync frame. */
89        int64_t mTimeUs;
90    };
91
92    ATSParser(uint32_t flags = 0);
93
94    // Feed a TS packet into the parser. uninitialized event with the start
95    // offset of this TS packet goes in, and if the parser detects PES with
96    // a sync frame, the event will be initiailzed with the start offset of the
97    // PES. Note that the offset of the event can be different from what we fed,
98    // as a PES may consist of multiple TS packets.
99    //
100    // Even in the case feedTSPacket() returns non-OK value, event still may be
101    // initialized if the parsing failed after the detection.
102    status_t feedTSPacket(
103            const void *data, size_t size, SyncEvent *event = NULL);
104
105    void signalDiscontinuity(
106            DiscontinuityType type, const sp<AMessage> &extra);
107
108    void signalEOS(status_t finalResult);
109
110    enum SourceType {
111        VIDEO = 0,
112        AUDIO = 1,
113        META  = 2,
114        NUM_SOURCE_TYPES = 3
115    };
116    sp<MediaSource> getSource(SourceType type);
117    bool hasSource(SourceType type) const;
118
119    bool PTSTimeDeltaEstablished();
120
121    enum {
122        // From ISO/IEC 13818-1: 2000 (E), Table 2-29
123        STREAMTYPE_RESERVED             = 0x00,
124        STREAMTYPE_MPEG1_VIDEO          = 0x01,
125        STREAMTYPE_MPEG2_VIDEO          = 0x02,
126        STREAMTYPE_MPEG1_AUDIO          = 0x03,
127        STREAMTYPE_MPEG2_AUDIO          = 0x04,
128        STREAMTYPE_MPEG2_AUDIO_ADTS     = 0x0f,
129        STREAMTYPE_MPEG4_VIDEO          = 0x10,
130        STREAMTYPE_METADATA             = 0x15,
131        STREAMTYPE_H264                 = 0x1b,
132
133        // From ATSC A/53 Part 3:2009, 6.7.1
134        STREAMTYPE_AC3                  = 0x81,
135
136        // Stream type 0x83 is non-standard,
137        // it could be LPCM or TrueHD AC3
138        STREAMTYPE_LPCM_AC3             = 0x83,
139    };
140
141protected:
142    virtual ~ATSParser();
143
144private:
145    struct Program;
146    struct Stream;
147    struct PSISection;
148
149    uint32_t mFlags;
150    Vector<sp<Program> > mPrograms;
151
152    // Keyed by PID
153    KeyedVector<unsigned, sp<PSISection> > mPSISections;
154
155    int64_t mAbsoluteTimeAnchorUs;
156
157    bool mTimeOffsetValid;
158    int64_t mTimeOffsetUs;
159    int64_t mLastRecoveredPTS;
160
161    size_t mNumTSPacketsParsed;
162
163    void parseProgramAssociationTable(ABitReader *br);
164    void parseProgramMap(ABitReader *br);
165    // Parse PES packet where br is pointing to. If the PES contains a sync
166    // frame, set event with the time and the start offset of this PES.
167    // Note that the method itself does not touch event.
168    void parsePES(ABitReader *br, SyncEvent *event);
169
170    // Strip remaining packet headers and pass to appropriate program/stream
171    // to parse the payload. If the payload turns out to be PES and contains
172    // a sync frame, event shall be set with the time and start offset of the
173    // PES.
174    // Note that the method itself does not touch event.
175    status_t parsePID(
176        ABitReader *br, unsigned PID,
177        unsigned continuity_counter,
178        unsigned payload_unit_start_indicator,
179        SyncEvent *event);
180
181    status_t parseAdaptationField(ABitReader *br, unsigned PID);
182    // see feedTSPacket().
183    status_t parseTS(ABitReader *br, SyncEvent *event);
184
185    void updatePCR(unsigned PID, uint64_t PCR, uint64_t byteOffsetFromStart);
186
187    uint64_t mPCR[2];
188    uint64_t mPCRBytes[2];
189    int64_t mSystemTimeUs[2];
190    size_t mNumPCRs;
191
192    DISALLOW_EVIL_CONSTRUCTORS(ATSParser);
193};
194
195}  // namespace android
196
197#endif  // A_TS_PARSER_H_
198