1/* 2 * Copyright (C) 2009 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 IMEDIA_SOURCE_BASE_H_ 18 19#define IMEDIA_SOURCE_BASE_H_ 20 21#include <map> 22 23#include <binder/IInterface.h> 24#include <binder/IMemory.h> 25#include <media/MediaSource.h> 26#include <media/stagefright/MediaBuffer.h> 27#include <media/stagefright/MediaErrors.h> 28 29namespace android { 30 31class MediaBufferGroup; 32 33class IMediaSource : public IInterface { 34public: 35 DECLARE_META_INTERFACE(MediaSource); 36 37 enum { 38 // Maximum number of buffers would be read in readMultiple. 39 kMaxNumReadMultiple = 128, 40 }; 41 42 // To be called before any other methods on this object, except 43 // getFormat(). 44 virtual status_t start(MetaData *params = NULL) = 0; 45 46 // Any blocking read call returns immediately with a result of NO_INIT. 47 // It is an error to call any methods other than start after this call 48 // returns. Any buffers the object may be holding onto at the time of 49 // the stop() call are released. 50 // Also, it is imperative that any buffers output by this object and 51 // held onto by callers be released before a call to stop() !!! 52 virtual status_t stop() = 0; 53 54 // Returns the format of the data output by this media source. 55 virtual sp<MetaData> getFormat() = 0; 56 57 // Returns a new buffer of data. Call blocks until a 58 // buffer is available, an error is encountered or the end of the stream 59 // is reached. 60 // End of stream is signalled by a result of ERROR_END_OF_STREAM. 61 // A result of INFO_FORMAT_CHANGED indicates that the format of this 62 // MediaSource has changed mid-stream, the client can continue reading 63 // but should be prepared for buffers of the new configuration. 64 // 65 // TODO: consider removing read() in favor of readMultiple(). 66 virtual status_t read( 67 MediaBufferBase **buffer, 68 const MediaSource::ReadOptions *options = NULL) = 0; 69 70 // Returns a vector of new buffers of data, where the new buffers are added 71 // to the end of the vector. 72 // Call blocks until an error is encountered, or the end of the stream is 73 // reached, or format change is hit, or |kMaxNumReadMultiple| buffers have 74 // been read. 75 // End of stream is signaled by a result of ERROR_END_OF_STREAM. 76 // A result of INFO_FORMAT_CHANGED indicates that the format of this 77 // MediaSource has changed mid-stream, the client can continue reading 78 // but should be prepared for buffers of the new configuration. 79 // 80 // ReadOptions may be specified. Persistent options apply to all reads; 81 // non-persistent options (e.g. seek) apply only to the first read. 82 virtual status_t readMultiple( 83 Vector<MediaBufferBase *> *buffers, uint32_t maxNumBuffers = 1, 84 const MediaSource::ReadOptions *options = nullptr) = 0; 85 86 // Returns true if |readMultiple| is supported, otherwise false. 87 virtual bool supportReadMultiple() = 0; 88 89 // Returns true if |read| supports nonblocking option, otherwise false. 90 // |readMultiple| if supported, always allows the nonblocking option. 91 virtual bool supportNonblockingRead() = 0; 92 93 // Causes this source to suspend pulling data from its upstream source 94 // until a subsequent read-with-seek. Currently only supported by 95 // OMXCodec. 96 virtual status_t pause() = 0; 97}; 98 99class BnMediaSource: public BnInterface<IMediaSource> 100{ 101public: 102 BnMediaSource(); 103 104 virtual status_t onTransact(uint32_t code, const Parcel& data, Parcel* reply, 105 uint32_t flags = 0); 106 107 virtual status_t pause() { 108 return ERROR_UNSUPPORTED; 109 } 110 111 // TODO: Implement this for local media sources. 112 virtual status_t readMultiple( 113 Vector<MediaBufferBase *> * /* buffers */, uint32_t /* maxNumBuffers = 1 */, 114 const MediaSource::ReadOptions * /* options = nullptr */) { 115 return ERROR_UNSUPPORTED; 116 } 117 118 virtual bool supportReadMultiple() { 119 return false; 120 } 121 122 // Override in source if nonblocking reads are supported. 123 virtual bool supportNonblockingRead() { 124 return false; 125 } 126 127 static const size_t kBinderMediaBuffers = 4; // buffers managed by BnMediaSource 128 static const size_t kTransferSharedAsSharedThreshold = 4 * 1024; // if >= shared, else inline 129 static const size_t kTransferInlineAsSharedThreshold = 64 * 1024; // if >= shared, else inline 130 static const size_t kInlineMaxTransfer = 256 * 1024; // Binder size limited to BINDER_VM_SIZE. 131 132protected: 133 virtual ~BnMediaSource(); 134 135private: 136 uint32_t mBuffersSinceStop; // Buffer tracking variable 137 138 std::unique_ptr<MediaBufferGroup> mGroup; 139 140 // To prevent marshalling IMemory with each read transaction, we cache the IMemory pointer 141 // into a map. 142 // 143 // This is converted into an index, which is used to identify the associated memory 144 // on the receiving side. We hold a reference to the IMemory here to ensure it doesn't 145 // change underneath us. 146 147 struct IndexCache { 148 IndexCache() : mIndex(0) { } 149 150 // Returns the index of the IMemory stored in cache or 0 if not found. 151 uint64_t lookup(const sp<IMemory> &mem) { 152 auto p = mMemoryToIndex.find(mem.get()); 153 if (p == mMemoryToIndex.end()) { 154 return 0; 155 } 156 if (MediaBuffer::isDeadObject(p->second.first)) { 157 // this object's dead 158 ALOGW("Attempting to lookup a dead IMemory"); 159 (void)mMemoryToIndex.erase(p); 160 return 0; 161 } 162 ALOGW_IF(p->second.first.get() != mem.get(), "Mismatched buffers without reset"); 163 return p->second.second; 164 } 165 166 // Returns the index of the IMemory stored in the index cache. 167 uint64_t insert(const sp<IMemory> &mem) { 168 auto p = mMemoryToIndex.find(mem.get()); 169 if (p == mMemoryToIndex.end()) { 170 if (mIndex == UINT64_MAX) { 171 ALOGE("Index overflow"); 172 mIndex = 1; // skip overflow condition and hope for the best 173 } else { 174 ++mIndex; 175 } 176 (void)mMemoryToIndex.emplace(// C++11 mem.get(), std::make_pair(mem, mIndex)) 177 std::piecewise_construct, 178 std::forward_as_tuple(mem.get()), std::forward_as_tuple(mem, mIndex)); 179 return mIndex; 180 } 181 ALOGW("IMemory already inserted into cache"); 182 return p->second.second; 183 } 184 185 void reset() { 186 mMemoryToIndex.clear(); 187 mIndex = 0; 188 } 189 190 void gc() { 191 for (auto it = mMemoryToIndex.begin(); it != mMemoryToIndex.end(); ) { 192 if (MediaBuffer::isDeadObject(it->second.first)) { 193 it = mMemoryToIndex.erase(it); 194 } else { 195 ++it; 196 } 197 } 198 } 199 200 private: 201 uint64_t mIndex; 202 // C++14 unordered_map erase on iterator is stable; C++11 has no guarantee. 203 // Could key on uintptr_t instead of IMemory * 204 std::map<IMemory *, std::pair<sp<IMemory>, uint64_t>> mMemoryToIndex; 205 } mIndexCache; 206}; 207 208} // namespace android 209 210#endif // IMEDIA_SOURCE_BASE_H_ 211