LiveSession.h revision b44ce2f84691559672cfaf6bb8fd3a9ac43904f2 
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 LIVE_SESSION_H_
18
19#define LIVE_SESSION_H_
20
21#include <media/stagefright/foundation/AHandler.h>
22
23#include <utils/String8.h>
24
25namespace android {
26
27struct ABuffer;
28struct AnotherPacketSource;
29struct DataSource;
30struct HTTPBase;
31struct IMediaHTTPService;
32struct LiveDataSource;
33struct M3UParser;
34struct PlaylistFetcher;
35struct Parcel;
36
37struct LiveSession : public AHandler {
38    enum Flags {
39        // Don't log any URLs.
40        kFlagIncognito = 1,
41    };
42    LiveSession(
43            const sp<AMessage> &notify,
44            uint32_t flags,
45            const sp<IMediaHTTPService> &httpService);
46
47    enum StreamIndex {
48        kAudioIndex    = 0,
49        kVideoIndex    = 1,
50        kSubtitleIndex = 2,
51        kMaxStreams    = 3,
52    };
53
54    enum StreamType {
55        STREAMTYPE_AUDIO        = 1 << kAudioIndex,
56        STREAMTYPE_VIDEO        = 1 << kVideoIndex,
57        STREAMTYPE_SUBTITLES    = 1 << kSubtitleIndex,
58    };
59    status_t dequeueAccessUnit(StreamType stream, sp<ABuffer> *accessUnit);
60
61    status_t getStreamFormat(StreamType stream, sp<AMessage> *format);
62
63    void connectAsync(
64            const char *url,
65            const KeyedVector<String8, String8> *headers = NULL);
66
67    status_t disconnect();
68
69    // Blocks until seek is complete.
70    status_t seekTo(int64_t timeUs);
71
72    status_t getDuration(int64_t *durationUs) const;
73    size_t getTrackCount() const;
74    sp<AMessage> getTrackInfo(size_t trackIndex) const;
75    status_t selectTrack(size_t index, bool select);
76
77    bool isSeekable() const;
78    bool hasDynamicDuration() const;
79
80    enum {
81        kWhatStreamsChanged,
82        kWhatError,
83        kWhatPrepared,
84        kWhatPreparationFailed,
85    };
86
87    // create a format-change discontinuity
88    //
89    // swap:
90    //   whether is format-change discontinuity should trigger a buffer swap
91    sp<ABuffer> createFormatChangeBuffer(bool swap = true);
92protected:
93    virtual ~LiveSession();
94
95    virtual void onMessageReceived(const sp<AMessage> &msg);
96
97private:
98    friend struct PlaylistFetcher;
99
100    enum {
101        kWhatConnect                    = 'conn',
102        kWhatDisconnect                 = 'disc',
103        kWhatSeek                       = 'seek',
104        kWhatFetcherNotify              = 'notf',
105        kWhatCheckBandwidth             = 'bndw',
106        kWhatChangeConfiguration        = 'chC0',
107        kWhatChangeConfiguration2       = 'chC2',
108        kWhatChangeConfiguration3       = 'chC3',
109        kWhatFinishDisconnect2          = 'fin2',
110        kWhatSwapped                    = 'swap',
111        kWhatCheckSwitchDown            = 'ckSD',
112        kWhatSwitchDown                 = 'sDwn',
113    };
114
115    struct BandwidthItem {
116        size_t mPlaylistIndex;
117        unsigned long mBandwidth;
118    };
119
120    struct FetcherInfo {
121        sp<PlaylistFetcher> mFetcher;
122        int64_t mDurationUs;
123        bool mIsPrepared;
124        bool mToBeRemoved;
125    };
126
127    struct StreamItem {
128        const char *mType;
129        AString mUri, mNewUri;
130        size_t mCurDiscontinuitySeq;
131        int64_t mLastDequeuedTimeUs;
132        int64_t mLastSampleDurationUs;
133        StreamItem()
134            : mType(""),
135              mCurDiscontinuitySeq(0),
136              mLastDequeuedTimeUs(0),
137              mLastSampleDurationUs(0) {}
138        StreamItem(const char *type)
139            : mType(type),
140              mCurDiscontinuitySeq(0),
141              mLastDequeuedTimeUs(0),
142              mLastSampleDurationUs(0) {}
143        AString uriKey() {
144            AString key(mType);
145            key.append("URI");
146            return key;
147        }
148    };
149    StreamItem mStreams[kMaxStreams];
150
151    sp<AMessage> mNotify;
152    uint32_t mFlags;
153    sp<IMediaHTTPService> mHTTPService;
154
155    bool mInPreparationPhase;
156    bool mBuffering[kMaxStreams];
157
158    sp<HTTPBase> mHTTPDataSource;
159    KeyedVector<String8, String8> mExtraHeaders;
160
161    AString mMasterURL;
162
163    Vector<BandwidthItem> mBandwidthItems;
164    ssize_t mCurBandwidthIndex;
165
166    sp<M3UParser> mPlaylist;
167
168    KeyedVector<AString, FetcherInfo> mFetcherInfos;
169    uint32_t mStreamMask;
170
171    // Masks used during reconfiguration:
172    // mNewStreamMask: streams in the variant playlist we're switching to;
173    // we don't want to immediately overwrite the original value.
174    uint32_t mNewStreamMask;
175
176    // mSwapMask: streams that have started to playback content in the new variant playlist;
177    // we use this to track reconfiguration progress.
178    uint32_t mSwapMask;
179
180    KeyedVector<StreamType, sp<AnotherPacketSource> > mDiscontinuities;
181    KeyedVector<StreamType, sp<AnotherPacketSource> > mPacketSources;
182    // A second set of packet sources that buffer content for the variant we're switching to.
183    KeyedVector<StreamType, sp<AnotherPacketSource> > mPacketSources2;
184
185    // A mutex used to serialize two sets of events:
186    // * the swapping of packet sources in dequeueAccessUnit on the player thread, AND
187    // * a forced bandwidth switch termination in cancelSwitch on the live looper.
188    Mutex mSwapMutex;
189
190    int32_t mCheckBandwidthGeneration;
191    int32_t mSwitchGeneration;
192    int32_t mSubtitleGeneration;
193
194    size_t mContinuationCounter;
195    sp<AMessage> mContinuation;
196    sp<AMessage> mSeekReply;
197
198    int64_t mLastDequeuedTimeUs;
199    int64_t mRealTimeBaseUs;
200
201    bool mReconfigurationInProgress;
202    bool mSwitchInProgress;
203    uint32_t mDisconnectReplyID;
204    uint32_t mSeekReplyID;
205
206    bool mFirstTimeUsValid;
207    int64_t mFirstTimeUs;
208    int64_t mLastSeekTimeUs;
209    sp<AMessage> mSwitchDownMonitor;
210    KeyedVector<size_t, int64_t> mDiscontinuityAbsStartTimesUs;
211    KeyedVector<size_t, int64_t> mDiscontinuityOffsetTimesUs;
212
213    sp<PlaylistFetcher> addFetcher(const char *uri);
214
215    void onConnect(const sp<AMessage> &msg);
216    status_t onSeek(const sp<AMessage> &msg);
217    void onFinishDisconnect2();
218
219    // If given a non-zero block_size (default 0), it is used to cap the number of
220    // bytes read in from the DataSource. If given a non-NULL buffer, new content
221    // is read into the end.
222    //
223    // The DataSource we read from is responsible for signaling error or EOF to help us
224    // break out of the read loop. The DataSource can be returned to the caller, so
225    // that the caller can reuse it for subsequent fetches (within the initially
226    // requested range).
227    //
228    // For reused HTTP sources, the caller must download a file sequentially without
229    // any overlaps or gaps to prevent reconnection.
230    ssize_t fetchFile(
231            const char *url, sp<ABuffer> *out,
232            /* request/open a file starting at range_offset for range_length bytes */
233            int64_t range_offset = 0, int64_t range_length = -1,
234            /* download block size */
235            uint32_t block_size = 0,
236            /* reuse DataSource if doing partial fetch */
237            sp<DataSource> *source = NULL,
238            String8 *actualUrl = NULL);
239
240    sp<M3UParser> fetchPlaylist(
241            const char *url, uint8_t *curPlaylistHash, bool *unchanged);
242
243    size_t getBandwidthIndex();
244    int64_t latestMediaSegmentStartTimeUs();
245
246    static int SortByBandwidth(const BandwidthItem *, const BandwidthItem *);
247    static StreamType indexToType(int idx);
248    static ssize_t typeToIndex(int32_t type);
249
250    void changeConfiguration(
251            int64_t timeUs, size_t bandwidthIndex, bool pickTrack = false);
252    void onChangeConfiguration(const sp<AMessage> &msg);
253    void onChangeConfiguration2(const sp<AMessage> &msg);
254    void onChangeConfiguration3(const sp<AMessage> &msg);
255    void onSwapped(const sp<AMessage> &msg);
256    void onCheckSwitchDown();
257    void onSwitchDown();
258    void tryToFinishBandwidthSwitch();
259
260    void scheduleCheckBandwidthEvent();
261    void cancelCheckBandwidthEvent();
262
263    // cancelBandwidthSwitch is atomic wrt swapPacketSource; call it to prevent packet sources
264    // from being swapped out on stale discontinuities while manipulating
265    // mPacketSources/mPacketSources2.
266    void cancelBandwidthSwitch();
267
268    bool canSwitchBandwidthTo(size_t bandwidthIndex);
269    void onCheckBandwidth(const sp<AMessage> &msg);
270
271    void finishDisconnect();
272
273    void postPrepared(status_t err);
274
275    void swapPacketSource(StreamType stream);
276    bool canSwitchUp();
277
278    DISALLOW_EVIL_CONSTRUCTORS(LiveSession);
279};
280
281}  // namespace android
282
283#endif  // LIVE_SESSION_H_
284