audio_player.cpp

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/*
 * Copyright 2015 The Android Open Source Project
 * Copyright 2015-2025 Savoir-faire Linux Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
 
#include "audio_player.h"
#include "logger.h"
 
#include <SLES/OpenSLES_AndroidConfiguration.h>
 
#include <cstdlib>
 
namespace jami {
namespace opensl {
 
/*
 * Called by OpenSL SimpleBufferQueue for every audio buffer played
 * directly pass through to our handler.
 * The regularity of this callback from openSL/Android System affects
 * playback continuity. If it does not callback in the regular time
 * slot, you are under big pressure for audio processing[here we do
 * not do any filtering/mixing]. Callback from fast audio path are
 * much more regular than other audio paths by my observation. If it
 * very regular, you could buffer much less audio samples between
 * recorder and player, hence lower latency.
 */
void
bqPlayerCallback(SLAndroidSimpleBufferQueueItf bq, void* ctx)
{
    (static_cast<AudioPlayer*>(ctx))->processSLCallback(bq);
}
 
void
AudioPlayer::processSLCallback(SLAndroidSimpleBufferQueueItf bq)
{
    std::unique_lock lk(m_, std::defer_lock);
    if (!lk.try_lock())
        return;
 
    // retrieve the finished device buf and put onto the free queue
    // so recorder could re-use it
    sample_buf* buf;
    if (!devShadowQueue_.front(&buf)) {
        JAMI_ERR("AudioPlayer buffer lost");
        /*
         * This should not happen: we got a callback,
         * but we have no buffer in deviceShadowedQueue
         * we lost buffers this way...(ERROR)
         */
        return;
    }
    devShadowQueue_.pop();
 
    if (buf != &silentBuf_) {
        buf->size_ = 0;
        if (!freeQueue_->push(buf)) {
            JAMI_ERR("buffer lost");
        }
    }
 
    if (callback_)
        callback_();
 
    while (playQueue_->front(&buf) && devShadowQueue_.push(buf)) {
        if ((*bq)->Enqueue(bq, buf->buf_, buf->size_) != SL_RESULT_SUCCESS) {
            devShadowQueue_.pop();
            JAMI_ERR("enqueue failed %zu %d %d %d",
                     buf->size_,
                     freeQueue_->size(),
                     playQueue_->size(),
                     devShadowQueue_.size());
            break;
        } else
            playQueue_->pop();
    }
    if (devShadowQueue_.size() == 0) {
        for (int i = 0; i < DEVICE_SHADOW_BUFFER_QUEUE_LEN; i++) {
            if ((*bq)->Enqueue(bq, silentBuf_.buf_, silentBuf_.size_) == SL_RESULT_SUCCESS) {
                devShadowQueue_.push(&silentBuf_);
            } else {
                JAMI_ERR("Enqueue silentBuf_ failed");
            }
        }
    }
}
 
AudioPlayer::AudioPlayer(jami::AudioFormat sampleFormat,
                         size_t bufSize,
                         SLEngineItf slEngine,
                         SLint32 streamType)
    : sampleInfo_(sampleFormat)
{
    JAMI_DBG("Creating OpenSL playback stream %s", sampleFormat.toString().c_str());
 
    SLresult result;
    result = (*slEngine)->CreateOutputMix(slEngine, &outputMixObjectItf_, 0, nullptr, nullptr);
    SLASSERT(result);
 
    // realize the output mix
    result = (*outputMixObjectItf_)->Realize(outputMixObjectItf_, SL_BOOLEAN_FALSE);
    SLASSERT(result);
 
    // configure audio source
    SLDataLocator_AndroidSimpleBufferQueue loc_bufq = {SL_DATALOCATOR_ANDROIDSIMPLEBUFFERQUEUE,
                                                       DEVICE_SHADOW_BUFFER_QUEUE_LEN};
 
    auto format_pcm = convertToSLSampleFormat(sampleInfo_);
    SLDataSource audioSrc = {&loc_bufq, &format_pcm};
 
    // configure audio sink
    SLDataLocator_OutputMix loc_outmix = {SL_DATALOCATOR_OUTPUTMIX, outputMixObjectItf_};
    SLDataSink audioSnk = {&loc_outmix, nullptr};
    /*
     * create fast path audio player: SL_IID_BUFFERQUEUE and SL_IID_VOLUME interfaces ok,
     * NO others!
     */
    SLInterfaceID ids[3] = {SL_IID_BUFFERQUEUE, SL_IID_VOLUME, SL_IID_ANDROIDCONFIGURATION};
    SLboolean req[3] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};
    result = (*slEngine)->CreateAudioPlayer(slEngine,
                                            &playerObjectItf_,
                                            &audioSrc,
                                            &audioSnk,
                                            sizeof(ids) / sizeof(ids[0]),
                                            ids,
                                            req);
    SLASSERT(result);
 
    SLAndroidConfigurationItf playerConfig;
    result = (*playerObjectItf_)
                 ->GetInterface(playerObjectItf_, SL_IID_ANDROIDCONFIGURATION, &playerConfig);
    result = (*playerConfig)
                 ->SetConfiguration(playerConfig,
                                    SL_ANDROID_KEY_STREAM_TYPE,
                                    &streamType,
                                    sizeof(SLint32));
 
    // realize the player
    result = (*playerObjectItf_)->Realize(playerObjectItf_, SL_BOOLEAN_FALSE);
    SLASSERT(result);
 
    // get the play interface
    result = (*playerObjectItf_)->GetInterface(playerObjectItf_, SL_IID_PLAY, &playItf_);
    SLASSERT(result);
 
    // get the buffer queue interface
    result = (*playerObjectItf_)
                 ->GetInterface(playerObjectItf_, SL_IID_BUFFERQUEUE, &playBufferQueueItf_);
    SLASSERT(result);
 
    // register callback on the buffer queue
    result = (*playBufferQueueItf_)->RegisterCallback(playBufferQueueItf_, bqPlayerCallback, this);
    SLASSERT(result);
 
    result = (*playItf_)->SetPlayState(playItf_, SL_PLAYSTATE_STOPPED);
    SLASSERT(result);
 
    silentBuf_ = {(format_pcm.containerSize >> 3) * format_pcm.numChannels * bufSize};
    silentBuf_.size_ = silentBuf_.cap_;
    av_samples_set_silence(&silentBuf_.buf_, 0, (int)bufSize, (int)sampleInfo_.nb_channels, sampleInfo_.sampleFormat);
}
 
AudioPlayer::~AudioPlayer()
{
    JAMI_DBG("Destroying OpenSL playback stream");
    std::lock_guard lk(m_);
 
    // destroy buffer queue audio player object, and invalidate all associated interfaces
    if (playerObjectItf_) {
        (*playerObjectItf_)->Destroy(playerObjectItf_);
    }
 
    // destroy output mix object, and invalidate all associated interfaces
    if (outputMixObjectItf_) {
        (*outputMixObjectItf_)->Destroy(outputMixObjectItf_);
    }
}
 
void
AudioPlayer::setBufQueue(AudioQueue* playQ, AudioQueue* freeQ)
{
    playQueue_ = playQ;
    freeQueue_ = freeQ;
}
 
bool
AudioPlayer::start()
{
    JAMI_DBG("OpenSL playback start");
    std::unique_lock lk(m_);
    SLuint32 state;
    SLresult result = (*playItf_)->GetPlayState(playItf_, &state);
    if (result != SL_RESULT_SUCCESS)
        return false;
    if (state == SL_PLAYSTATE_PLAYING)
        return true;
 
    result = (*playItf_)->SetPlayState(playItf_, SL_PLAYSTATE_STOPPED);
    SLASSERT(result);
 
    devShadowQueue_.push(&silentBuf_);
    result = (*playBufferQueueItf_)->Enqueue(playBufferQueueItf_, silentBuf_.buf_, silentBuf_.size_);
    if (result != SL_RESULT_SUCCESS) {
        JAMI_ERR("Enqueue silentBuf_ failed, result = %d", result);
        devShadowQueue_.pop();
    }
 
    lk.unlock();
    result = (*playItf_)->SetPlayState(playItf_, SL_PLAYSTATE_PLAYING);
    SLASSERT(result);
 
    return true;
}
 
bool
AudioPlayer::started() const
{
    if (!playItf_)
        return false;
    SLuint32 state;
    SLresult result = (*playItf_)->GetPlayState(playItf_, &state);
    return result == SL_RESULT_SUCCESS && state == SL_PLAYSTATE_PLAYING;
}
 
void
AudioPlayer::stop()
{
    JAMI_DBG("OpenSL playback stop");
    SLuint32 state;
 
    std::lock_guard lk(m_);
    SLresult result = (*playItf_)->GetPlayState(playItf_, &state);
    SLASSERT(result);
 
    if (state == SL_PLAYSTATE_STOPPED)
        return;
 
    callback_ = {};
    result = (*playItf_)->SetPlayState(playItf_, SL_PLAYSTATE_STOPPED);
    SLASSERT(result);
 
    // Consume all non-completed audio buffers
    sample_buf* buf = nullptr;
    while (devShadowQueue_.front(&buf)) {
        buf->size_ = 0;
        devShadowQueue_.pop();
        freeQueue_->push(buf);
    }
    while (playQueue_->front(&buf)) {
        buf->size_ = 0;
        playQueue_->pop();
        freeQueue_->push(buf);
    }
}
 
void
AudioPlayer::playAudioBuffers(unsigned count)
{
    while (count--) {
        sample_buf* buf = nullptr;
        if (!playQueue_->front(&buf)) {
            JAMI_ERR("====Run out of buffers in %s @(count = %d)", __FUNCTION__, count);
            break;
        }
        if (!devShadowQueue_.push(buf)) {
            break; // PlayerBufferQueue is full!!!
        }
 
        SLresult result = (*playBufferQueueItf_)->Enqueue(playBufferQueueItf_, buf->buf_, buf->size_);
        if (result != SL_RESULT_SUCCESS) {
            JAMI_ERR("%s Error @( %p, %zu ), result = %d",
                     __FUNCTION__,
                     (void*) buf->buf_,
                     buf->size_,
                     result);
            /*
             * when this happens, a buffer is lost. Need to remove the buffer
             * from top of the devShadowQueue. Since I do not have it now,
             * just pop out the one that is being played right now. Afer a
             * cycle it will be normal.
             */
            devShadowQueue_.front(&buf), devShadowQueue_.pop();
            freeQueue_->push(buf);
            break;
        }
        playQueue_->pop(); // really pop out the buffer
    }
}
 
size_t
AudioPlayer::dbgGetDevBufCount(void)
{
    return devShadowQueue_.size();
}
 
} // namespace opensl
} // namespace jami