PlaylistFetcher.h revision 8564e13b37d372da78bce08f34a3610795ae173c
1/* 2 * Copyright (C) 2012 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 PLAYLIST_FETCHER_H_ 18 19#define PLAYLIST_FETCHER_H_ 20 21#include <media/stagefright/foundation/AHandler.h> 22 23#include "mpeg2ts/ATSParser.h" 24#include "LiveSession.h" 25 26namespace android { 27 28struct ABuffer; 29struct AnotherPacketSource; 30struct DataSource; 31struct HTTPBase; 32struct LiveDataSource; 33struct M3UParser; 34class String8; 35 36struct PlaylistFetcher : public AHandler { 37 static const int64_t kMinBufferedDurationUs; 38 static const int32_t kDownloadBlockSize; 39 40 enum { 41 kWhatStarted, 42 kWhatPaused, 43 kWhatStopped, 44 kWhatError, 45 kWhatDurationUpdate, 46 kWhatTemporarilyDoneFetching, 47 kWhatPrepared, 48 kWhatPreparationFailed, 49 kWhatStartedAt, 50 }; 51 52 PlaylistFetcher( 53 const sp<AMessage> ¬ify, 54 const sp<LiveSession> &session, 55 const char *uri, 56 int32_t subtitleGeneration); 57 58 sp<DataSource> getDataSource(); 59 60 void startAsync( 61 const sp<AnotherPacketSource> &audioSource, 62 const sp<AnotherPacketSource> &videoSource, 63 const sp<AnotherPacketSource> &subtitleSource, 64 int64_t startTimeUs = -1ll, // starting timestamps 65 int64_t segmentStartTimeUs = -1ll, // starting position within playlist 66 // startTimeUs!=segmentStartTimeUs only when playlist is live 67 int32_t startDiscontinuitySeq = 0, 68 bool adaptive = false); 69 70 void pauseAsync(); 71 72 void stopAsync(bool clear = true); 73 74 void resumeUntilAsync(const sp<AMessage> ¶ms); 75 76 uint32_t getStreamTypeMask() const { 77 return mStreamTypeMask; 78 } 79 80protected: 81 virtual ~PlaylistFetcher(); 82 virtual void onMessageReceived(const sp<AMessage> &msg); 83 84private: 85 enum { 86 kMaxNumRetries = 5, 87 }; 88 89 enum { 90 kWhatStart = 'strt', 91 kWhatPause = 'paus', 92 kWhatStop = 'stop', 93 kWhatMonitorQueue = 'moni', 94 kWhatResumeUntil = 'rsme', 95 kWhatDownloadNext = 'dlnx', 96 }; 97 98 static const int64_t kMaxMonitorDelayUs; 99 static const int32_t kNumSkipFrames; 100 101 static bool bufferStartsWithTsSyncByte(const sp<ABuffer>& buffer); 102 static bool bufferStartsWithWebVTTMagicSequence(const sp<ABuffer>& buffer); 103 104 // notifications to mSession 105 sp<AMessage> mNotify; 106 sp<AMessage> mStartTimeUsNotify; 107 108 sp<LiveSession> mSession; 109 AString mURI; 110 111 uint32_t mStreamTypeMask; 112 int64_t mStartTimeUs; 113 114 // Start time relative to the beginning of the first segment in the initial 115 // playlist. It's value is initialized to a non-negative value only when we are 116 // adapting or switching tracks. 117 int64_t mSegmentStartTimeUs; 118 119 ssize_t mDiscontinuitySeq; 120 bool mStartTimeUsRelative; 121 sp<AMessage> mStopParams; // message containing the latest timestamps we should fetch. 122 123 KeyedVector<LiveSession::StreamType, sp<AnotherPacketSource> > 124 mPacketSources; 125 126 KeyedVector<AString, sp<ABuffer> > mAESKeyForURI; 127 128 int64_t mLastPlaylistFetchTimeUs; 129 sp<M3UParser> mPlaylist; 130 int32_t mSeqNumber; 131 int32_t mNumRetries; 132 bool mStartup; 133 bool mAdaptive; 134 bool mPrepared; 135 int64_t mNextPTSTimeUs; 136 137 int32_t mMonitorQueueGeneration; 138 const int32_t mSubtitleGeneration; 139 140 enum RefreshState { 141 INITIAL_MINIMUM_RELOAD_DELAY, 142 FIRST_UNCHANGED_RELOAD_ATTEMPT, 143 SECOND_UNCHANGED_RELOAD_ATTEMPT, 144 THIRD_UNCHANGED_RELOAD_ATTEMPT 145 }; 146 RefreshState mRefreshState; 147 148 uint8_t mPlaylistHash[16]; 149 150 sp<ATSParser> mTSParser; 151 152 bool mFirstPTSValid; 153 uint64_t mFirstPTS; 154 int64_t mFirstTimeUs; 155 int64_t mAbsoluteTimeAnchorUs; 156 sp<AnotherPacketSource> mVideoBuffer; 157 158 // Stores the initialization vector to decrypt the next block of cipher text, which can 159 // either be derived from the sequence number, read from the manifest, or copied from 160 // the last block of cipher text (cipher-block chaining). 161 unsigned char mAESInitVec[16]; 162 163 // Set first to true if decrypting the first segment of a playlist segment. When 164 // first is true, reset the initialization vector based on the available 165 // information in the manifest; otherwise, use the initialization vector as 166 // updated by the last call to AES_cbc_encrypt. 167 // 168 // For the input to decrypt correctly, decryptBuffer must be called on 169 // consecutive byte ranges on block boundaries, e.g. 0..15, 16..47, 48..63, 170 // and so on. 171 status_t decryptBuffer( 172 size_t playlistIndex, const sp<ABuffer> &buffer, 173 bool first = true); 174 status_t checkDecryptPadding(const sp<ABuffer> &buffer); 175 176 void postMonitorQueue(int64_t delayUs = 0, int64_t minDelayUs = 0); 177 void cancelMonitorQueue(); 178 179 int64_t delayUsToRefreshPlaylist() const; 180 status_t refreshPlaylist(); 181 182 // Returns the media time in us of the segment specified by seqNumber. 183 // This is computed by summing the durations of all segments before it. 184 int64_t getSegmentStartTimeUs(int32_t seqNumber) const; 185 186 status_t onStart(const sp<AMessage> &msg); 187 void onPause(); 188 void onStop(const sp<AMessage> &msg); 189 void onMonitorQueue(); 190 void onDownloadNext(); 191 192 // Resume a fetcher to continue until the stopping point stored in msg. 193 status_t onResumeUntil(const sp<AMessage> &msg); 194 195 const sp<ABuffer> &setAccessUnitProperties( 196 const sp<ABuffer> &accessUnit, 197 const sp<AnotherPacketSource> &source, 198 bool discard = false); 199 status_t extractAndQueueAccessUnitsFromTs(const sp<ABuffer> &buffer); 200 201 status_t extractAndQueueAccessUnits( 202 const sp<ABuffer> &buffer, const sp<AMessage> &itemMeta); 203 204 void notifyError(status_t err); 205 206 void queueDiscontinuity( 207 ATSParser::DiscontinuityType type, const sp<AMessage> &extra); 208 209 int32_t getSeqNumberWithAnchorTime(int64_t anchorTimeUs) const; 210 int32_t getSeqNumberForDiscontinuity(size_t discontinuitySeq) const; 211 int32_t getSeqNumberForTime(int64_t timeUs) const; 212 213 void updateDuration(); 214 215 // Before resuming a fetcher in onResume, check the remaining duration is longer than that 216 // returned by resumeThreshold. 217 int64_t resumeThreshold(const sp<AMessage> &msg); 218 219 DISALLOW_EVIL_CONSTRUCTORS(PlaylistFetcher); 220}; 221 222} // namespace android 223 224#endif // PLAYLIST_FETCHER_H_ 225 226