Home | History | Annotate | Download | only in libstagefright 
      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 //#define LOG_NDEBUG 0
     18 #define LOG_TAG "MediaSourceSplitter"
     19 #include <utils/Log.h>
     20 
     21 #include <media/stagefright/MediaSourceSplitter.h>
     22 #include <media/stagefright/MediaDebug.h>
     23 #include <media/stagefright/MediaBuffer.h>
     24 #include <media/stagefright/MetaData.h>
     25 
     26 namespace android {
     27 
     28 MediaSourceSplitter::MediaSourceSplitter(sp<MediaSource> mediaSource) {
     29     mNumberOfClients = 0;
     30     mSource = mediaSource;
     31     mSourceStarted = false;
     32 
     33     mNumberOfClientsStarted = 0;
     34     mNumberOfCurrentReads = 0;
     35     mCurrentReadBit = 0;
     36     mLastReadCompleted = true;
     37 }
     38 
     39 MediaSourceSplitter::~MediaSourceSplitter() {
     40 }
     41 
     42 sp<MediaSource> MediaSourceSplitter::createClient() {
     43     Mutex::Autolock autoLock(mLock);
     44 
     45     sp<MediaSource> client = new Client(this, mNumberOfClients++);
     46     mClientsStarted.push(false);
     47     mClientsDesiredReadBit.push(0);
     48     return client;
     49 }
     50 
     51 status_t MediaSourceSplitter::start(int clientId, MetaData *params) {
     52     Mutex::Autolock autoLock(mLock);
     53 
     54     LOGV("start client (%d)", clientId);
     55     if (mClientsStarted[clientId]) {
     56         return OK;
     57     }
     58 
     59     mNumberOfClientsStarted++;
     60 
     61     if (!mSourceStarted) {
     62         LOGV("Starting real source from client (%d)", clientId);
     63         status_t err = mSource->start(params);
     64 
     65         if (err == OK) {
     66             mSourceStarted = true;
     67             mClientsStarted.editItemAt(clientId) = true;
     68             mClientsDesiredReadBit.editItemAt(clientId) = !mCurrentReadBit;
     69         }
     70 
     71         return err;
     72     } else {
     73         mClientsStarted.editItemAt(clientId) = true;
     74         if (mLastReadCompleted) {
     75             // Last read was completed. So join in the threads for the next read.
     76             mClientsDesiredReadBit.editItemAt(clientId) = !mCurrentReadBit;
     77         } else {
     78             // Last read is ongoing. So join in the threads for the current read.
     79             mClientsDesiredReadBit.editItemAt(clientId) = mCurrentReadBit;
     80         }
     81         return OK;
     82     }
     83 }
     84 
     85 status_t MediaSourceSplitter::stop(int clientId) {
     86     Mutex::Autolock autoLock(mLock);
     87 
     88     LOGV("stop client (%d)", clientId);
     89     CHECK(clientId >= 0 && clientId < mNumberOfClients);
     90     CHECK(mClientsStarted[clientId]);
     91 
     92     if (--mNumberOfClientsStarted == 0) {
     93         LOGV("Stopping real source from client (%d)", clientId);
     94         status_t err = mSource->stop();
     95         mSourceStarted = false;
     96         mClientsStarted.editItemAt(clientId) = false;
     97         return err;
     98     } else {
     99         mClientsStarted.editItemAt(clientId) = false;
    100         if (!mLastReadCompleted && (mClientsDesiredReadBit[clientId] == mCurrentReadBit)) {
    101             // !mLastReadCompleted implies that buffer has been read from source, but all
    102             // clients haven't read it.
    103             // mClientsDesiredReadBit[clientId] == mCurrentReadBit implies that this
    104             // client would have wanted to read from this buffer. (i.e. it has not yet
    105             // called read() for the current read buffer.)
    106             // Since other threads may be waiting for all the clients' reads to complete,
    107             // signal that this read has been aborted.
    108             signalReadComplete_lock(true);
    109         }
    110         return OK;
    111     }
    112 }
    113 
    114 sp<MetaData> MediaSourceSplitter::getFormat(int clientId) {
    115     Mutex::Autolock autoLock(mLock);
    116 
    117     LOGV("getFormat client (%d)", clientId);
    118     return mSource->getFormat();
    119 }
    120 
    121 status_t MediaSourceSplitter::read(int clientId,
    122         MediaBuffer **buffer, const MediaSource::ReadOptions *options) {
    123     Mutex::Autolock autoLock(mLock);
    124 
    125     CHECK(clientId >= 0 && clientId < mNumberOfClients);
    126 
    127     LOGV("read client (%d)", clientId);
    128     *buffer = NULL;
    129 
    130     if (!mClientsStarted[clientId]) {
    131         return OK;
    132     }
    133 
    134     if (mCurrentReadBit != mClientsDesiredReadBit[clientId]) {
    135         // Desired buffer has not been read from source yet.
    136 
    137         // If the current client is the special client with clientId = 0
    138         // then read from source, else wait until the client 0 has finished
    139         // reading from source.
    140         if (clientId == 0) {
    141             // Wait for all client's last read to complete first so as to not
    142             // corrupt the buffer at mLastReadMediaBuffer.
    143             waitForAllClientsLastRead_lock(clientId);
    144 
    145             readFromSource_lock(options);
    146             *buffer = mLastReadMediaBuffer;
    147         } else {
    148             waitForReadFromSource_lock(clientId);
    149 
    150             *buffer = mLastReadMediaBuffer;
    151             (*buffer)->add_ref();
    152         }
    153         CHECK(mCurrentReadBit == mClientsDesiredReadBit[clientId]);
    154     } else {
    155         // Desired buffer has already been read from source. Use the cached data.
    156         CHECK(clientId != 0);
    157 
    158         *buffer = mLastReadMediaBuffer;
    159         (*buffer)->add_ref();
    160     }
    161 
    162     mClientsDesiredReadBit.editItemAt(clientId) = !mClientsDesiredReadBit[clientId];
    163     signalReadComplete_lock(false);
    164 
    165     return mLastReadStatus;
    166 }
    167 
    168 void MediaSourceSplitter::readFromSource_lock(const MediaSource::ReadOptions *options) {
    169     mLastReadStatus = mSource->read(&mLastReadMediaBuffer , options);
    170 
    171     mCurrentReadBit = !mCurrentReadBit;
    172     mLastReadCompleted = false;
    173     mReadFromSourceCondition.broadcast();
    174 }
    175 
    176 void MediaSourceSplitter::waitForReadFromSource_lock(int32_t clientId) {
    177     mReadFromSourceCondition.wait(mLock);
    178 }
    179 
    180 void MediaSourceSplitter::waitForAllClientsLastRead_lock(int32_t clientId) {
    181     if (mLastReadCompleted) {
    182         return;
    183     }
    184     mAllReadsCompleteCondition.wait(mLock);
    185     CHECK(mLastReadCompleted);
    186 }
    187 
    188 void MediaSourceSplitter::signalReadComplete_lock(bool readAborted) {
    189     if (!readAborted) {
    190         mNumberOfCurrentReads++;
    191     }
    192 
    193     if (mNumberOfCurrentReads == mNumberOfClientsStarted) {
    194         mLastReadCompleted = true;
    195         mNumberOfCurrentReads = 0;
    196         mAllReadsCompleteCondition.broadcast();
    197     }
    198 }
    199 
    200 status_t MediaSourceSplitter::pause(int clientId) {
    201     return ERROR_UNSUPPORTED;
    202 }
    203 
    204 // Client
    205 
    206 MediaSourceSplitter::Client::Client(
    207         sp<MediaSourceSplitter> splitter,
    208         int32_t clientId) {
    209     mSplitter = splitter;
    210     mClientId = clientId;
    211 }
    212 
    213 status_t MediaSourceSplitter::Client::start(MetaData *params) {
    214     return mSplitter->start(mClientId, params);
    215 }
    216 
    217 status_t MediaSourceSplitter::Client::stop() {
    218     return mSplitter->stop(mClientId);
    219 }
    220 
    221 sp<MetaData> MediaSourceSplitter::Client::getFormat() {
    222     return mSplitter->getFormat(mClientId);
    223 }
    224 
    225 status_t MediaSourceSplitter::Client::read(
    226         MediaBuffer **buffer, const ReadOptions *options) {
    227     return mSplitter->read(mClientId, buffer, options);
    228 }
    229 
    230 status_t MediaSourceSplitter::Client::pause() {
    231     return mSplitter->pause(mClientId);
    232 }
    233 
    234 }  // namespace android
    235