video-pc/AvPlayer2/playercontroller.cpp

#include "playercontroller.h"

#include "common.h"

#include <QApplication>
#include <QElapsedTimer>
#include <QStatusBar>
#include <cassert>
#include <memory>

#include "ffmpeg_init.h"
#include "start_play_thread.h"
#include "video_state.h"

#include "audio_decode_thread.h"
#include "audio_effect_helper.h"
#include "audio_play_thread.h"
#include "play_control_window.h"
#include "read_thread.h"
#include "start_play_thread.h"
#include "stopplay_waiting_thread.h"
#include "subtitle_decode_thread.h"
#include "video_decode_thread.h"
#include "video_play_thread.h"
#include "video_state.h"

Q_LOGGING_CATEGORY(playerControllerLog, "player.controller")

PlayerController::PlayerController(QWidget* parent)
    : QObject(parent)
{
    ffmpeg_init();
    connect(this,
            &PlayerController::asyncInitFinished,
            this,
            &PlayerController::onAsyncInitFinished);
    m_state = PlayerState::Idle;
}

PlayerController::~PlayerController()
{
    if (m_initThread.joinable()) {
        m_initThread.join();
    }
    stopPlay();
}

void PlayerController::startToPlay(const QString& file)
{
    std::lock_guard<std::mutex> lock(m_stopMutex);
    // 自愈：如果状态为Playing但所有线程都已退出，强制Idle
    if (m_state == PlayerState::Playing) {
        if (!m_packetReadThread && !m_decodeVideoThread && !m_decodeAudioThread
            && !m_audioPlayThread && !m_videoPlayThread && !m_decodeSubtitleThread) {
            m_videoState.reset();
            m_currentFile.clear();
            m_state = PlayerState::Idle;
            qCDebug(playerControllerLog)
                << "[PlayerController] All threads stopped, force reset to Idle.";
        }
    }
    if (m_state == PlayerState::Initializing) {
        qCDebug(playerControllerLog) << "Player is initializing. Ignoring request.";
        return;
    }
    if (m_state == PlayerState::Playing) {
        if (m_currentFile == file) {
            qCDebug(playerControllerLog) << "Already playing the same file. Ignoring request.";
            return;
        } else {
            qCDebug(playerControllerLog)
                << "Player is busy with another file, stopping and switching to:" << file;
            stopPlay();
            // 这里直接 fallthrough 到 Idle 状态
        }
    }
    if (m_state == PlayerState::Idle) {
        qCDebug(playerControllerLog) << "Player is idle. Starting playback for:" << file;
        m_state = PlayerState::Initializing;
        m_currentFile = file;
        if (m_initThread.joinable()) {
            m_initThread.join();
        }
        m_initThread = std::thread(&PlayerController::asyncInit, this, file);
    }
}

void PlayerController::asyncInit(const QString& file)
{
    bool success = false;
    QElapsedTimer timer;
    timer.start();
    qCDebug(playerControllerLog) << "[Init] asyncInit started";
    if (file.isEmpty()) {
        qCWarning(playerControllerLog) << "Filename is invalid. Please select a valid media file.";
        success = false;
    } else {
        qCInfo(playerControllerLog) << "Check file: " << toNativePath(file);
        success = true;
    }
    m_initSuccess = success;
    emit asyncInitFinished(file, success);
    qCDebug(playerControllerLog) << "[Init] asyncInit finished in " << timer.elapsed() << " ms";
}

void PlayerController::onAsyncInitFinished(const QString& file, bool success)
{
    std::lock_guard<std::mutex> lock(m_stopMutex);
    if (!success) {
        playFailed(m_currentFile);
        m_state = PlayerState::Idle;
        return;
    }
    qCDebug(playerControllerLog) << "[Init] createReadThread...";
    if (!createReadThread()) {
        qCWarning(playerControllerLog) << "Packet read thread creation failed";
        playFailed(m_currentFile);
        m_state = PlayerState::Idle;
        return;
    }
    qCDebug(playerControllerLog) << "[Init] createVideoState...";
    if (!createVideoState(m_currentFile)) {
        qCWarning(playerControllerLog) << "Video state creation failed";
        readPacketStopped();
        playFailed(m_currentFile);
        m_state = PlayerState::Idle;
        return;
    }
    assert(m_videoState);
    if (!m_videoState) {
        qCWarning(playerControllerLog) << "Video state initialization error";
        playFailed(m_currentFile);
        m_state = PlayerState::Idle;
        return;
    }
    m_packetReadThread->set_video_state(m_videoState->get_state());
    const bool hasVideo = playingHasVideo();
    const bool hasAudio = playingHasAudio();
    const bool hasSubtitle = playingHasSubtitle();
    if (hasVideo) {
        if (!createDecodeVideoThread() || !createVideoPlayThread()) {
            qCWarning(playerControllerLog) << "Video processing setup failed";
            playFailed(m_currentFile);
            stopPlay();
            m_state = PlayerState::Idle;
            return;
        }
    }
    if (hasAudio) {
        if (!createDecodeAudioThread() || !createAudioPlayThread()) {
            qCWarning(playerControllerLog) << "Audio processing setup failed";
            playFailed(m_currentFile);
            stopPlay();
            m_state = PlayerState::Idle;
            return;
        }
    }
    if (hasSubtitle && !createDecodeSubtitleThread()) {
        qCWarning(playerControllerLog) << "Subtitle processing setup failed";
        playFailed(m_currentFile);
        stopPlay();
        m_state = PlayerState::Idle;
        return;
    }
    if (hasAudio) {
        startPlayThread();
    } else {
        playStarted();
    }
    emit startToPlaySignal();
    m_state = PlayerState::Playing;
}

void PlayerController::stopPlay()
{
    std::lock_guard<std::mutex> lock(m_stopMutex);
    if (m_state == PlayerState::Idle)
        return;
    m_state = PlayerState::Stopping;
    auto stopAndReset = [](auto& threadPtr) {
        if (threadPtr) {
            qCDebug(playerControllerLog) << "[stopAndReset] try stop/join thread, isRunning=" << threadPtr->isRunning();
            threadPtr->stop();
            threadPtr->join();
            qCDebug(playerControllerLog) << "[stopAndReset] thread joined and will reset.";
            threadPtr.reset();
        }
    };
    stopAndReset(m_stopPlayWaitingThread);
    stopAndReset(m_beforePlayThread);
    stopAndReset(m_packetReadThread);
    stopAndReset(m_decodeVideoThread);
    stopAndReset(m_decodeAudioThread);
    stopAndReset(m_decodeSubtitleThread);
    stopAndReset(m_videoPlayThread);
    stopAndReset(m_audioPlayThread);
    m_videoState.reset();
    m_currentFile.clear();
    m_state = PlayerState::Idle;
}

void PlayerController::pausePlay()
{
    if (!m_videoState)
        return;

    if (auto state = m_videoState->get_state())
        toggle_pause(state, !state->paused);

    emit updatePlayControlStatus();
}

void PlayerController::playMute(bool mute)
{
    if (!m_videoState)
        return;

    if (auto state = m_videoState->get_state())
        toggle_mute(state, mute);
}

void PlayerController::playStartSeek()
{
    emit playSeek();
    pausePlay();
}

void PlayerController::playSeekPre()
{
    videoSeekInc(-2);
}

void PlayerController::playSeekNext()
{
    videoSeekInc(2);
}

void PlayerController::setVolume(int volume, int maxValue)
{
    if (!m_audioPlayThread)
        return;

    const float vol = static_cast<float>(volume) / maxValue;
    m_audioPlayThread->set_device_volume(vol);
}

void PlayerController::setPlaySpeed(double speed)
{
    if (m_videoState) {
        if (auto state = m_videoState->get_state()) {
#if USE_AVFILTER_AUDIO
            set_audio_playspeed(state, speed);
#endif
        }
    }
}

// 状态访问接口
QString PlayerController::playingFile() const
{
    return isPlaying() ? m_currentFile : QString();
}

bool PlayerController::isPlaying() const
{
    return m_state == PlayerState::Playing;
}

bool PlayerController::playingHasVideo()
{
    return m_videoState ? m_videoState->has_video() : false;
}

bool PlayerController::playingHasAudio()
{
    return m_videoState ? m_videoState->has_audio() : false;
}

bool PlayerController::playingHasSubtitle()
{
    return m_videoState ? m_videoState->has_subtitle() : false;
}

VideoState* PlayerController::state()
{
    return m_videoState ? m_videoState->get_state() : nullptr;
}

float PlayerController::deviceVolume() const
{
    return m_audioPlayThread ? m_audioPlayThread->get_device_volume() : 0.0f;
}

void PlayerController::setDeviceVolume(float volume)
{
    if (m_audioPlayThread)
        m_audioPlayThread->set_device_volume(volume);
}

// 播放状态回调槽函数
void PlayerController::playStarted(bool success)
{
    if (!success) {
        qCWarning(playerControllerLog) << "Audio device initialization failed!";
        return;
    }

    allThreadStart();
    setThreads();
}

void PlayerController::playFailed(const QString& file)
{
    emit showMessage(QString("Playback failed: %1").arg(toNativePath(file)), "Warning", "");
}

// 线程 finished 槽函数只做日志和信号
void PlayerController::readPacketStopped()
{
    qCDebug(playerControllerLog) << "************* Read packets thread stopped signal received.";
    m_packetReadThread.reset();
    checkAndResetState();
    emit audioStopped();
}
void PlayerController::decodeVideoStopped()
{
    qCDebug(playerControllerLog) << "************* Video decode thread stopped.";
    m_decodeVideoThread.reset();
    checkAndResetState();
}
void PlayerController::decodeAudioStopped()
{
    qCDebug(playerControllerLog) << "************* Audio decode thread stopped.";
    m_decodeAudioThread.reset();
    checkAndResetState();
}
void PlayerController::decodeSubtitleStopped()
{
    qCDebug(playerControllerLog) << "************* Subtitle decode thread stopped.";
    m_decodeSubtitleThread.reset();
    checkAndResetState();
}
void PlayerController::audioPlayStopped()
{
    qCDebug(playerControllerLog) << "************* Audio play thread stopped.";
    emit audioStopped();
    m_audioPlayThread.reset();
    checkAndResetState();
}
void PlayerController::videoPlayStopped()
{
    qCDebug(playerControllerLog) << "************* Video play thread stopped.";
    emit videoStopped();
    m_videoPlayThread.reset();
    checkAndResetState();
}

// 线程管理槽函数
void PlayerController::setThreads()
{
    if (!m_videoState)
        return;

    Threads threads;
    threads.read_tid = m_packetReadThread.get();
    threads.video_decode_tid = m_decodeVideoThread.get();
    threads.audio_decode_tid = m_decodeAudioThread.get();
    threads.video_play_tid = m_videoPlayThread.get();
    threads.audio_play_tid = m_audioPlayThread.get();
    threads.subtitle_decode_tid = m_decodeSubtitleThread.get();

    m_videoState->threads_setting(m_videoState->get_state(), threads);
}

void PlayerController::startSendData(bool send)
{
    if (m_audioPlayThread)
        m_audioPlayThread->send_visual_open(send);
}

void PlayerController::videoSeek(double position, double increment)
{
    if (!m_videoState)
        return;

    auto state = m_videoState->get_state();
    if (!state)
        return;

    if (state->ic->start_time != AV_NOPTS_VALUE
        && position < state->ic->start_time / static_cast<double>(AV_TIME_BASE)) {
        position = state->ic->start_time / static_cast<double>(AV_TIME_BASE);
    }

    stream_seek(state,
                static_cast<int64_t>(position * AV_TIME_BASE),
                static_cast<int64_t>(increment * AV_TIME_BASE),
                0);
}

// 核心私有实现
bool PlayerController::startPlay()
{
    QElapsedTimer timer;
    timer.start();

    if (m_currentFile.isEmpty()) {
        qCWarning(playerControllerLog) << "Filename is invalid. Please select a valid media file.";
        return false;
    }

    qCInfo(playerControllerLog) << "Starting playback:" << toNativePath(m_currentFile);

    // 创建数据包读取线程
    if (!createReadThread()) {
        qCWarning(playerControllerLog) << "Packet read thread creation failed";
        return false;
    }

    // 创建视频状态对象
    if (!createVideoState(m_currentFile)) {
        qCWarning(playerControllerLog) << "Video state creation failed";
        readPacketStopped();
        return false;
    }

    // 检查状态有效性
    assert(m_videoState);
    if (!m_videoState) {
        qCWarning(playerControllerLog) << "Video state initialization error";
        return false;
    }

    m_packetReadThread->set_video_state(m_videoState->get_state());

    const bool hasVideo = playingHasVideo();
    const bool hasAudio = playingHasAudio();
    const bool hasSubtitle = playingHasSubtitle();

    // 创建视频相关线程
    if (hasVideo) {
        if (!createDecodeVideoThread() || !createVideoPlayThread()) {
            qCWarning(playerControllerLog) << "Video processing setup failed";
            return false;
        }
    }

    // 创建音频相关线程
    if (hasAudio) {
        if (!createDecodeAudioThread() || !createAudioPlayThread()) {
            qCWarning(playerControllerLog) << "Audio processing setup failed";
            return false;
        }
    }

    // 创建字幕线程
    if (hasSubtitle && !createDecodeSubtitleThread()) {
        qCWarning(playerControllerLog) << "Subtitle processing setup failed";
        return false;
    }

    // 开始播放
    if (hasAudio) {
        startPlayThread(); // 异步启动（处理音频设备初始化）
    } else {
        playStarted(); // 同步启动（无音频流）
    }

    qCDebug(playerControllerLog) << "Playback initialized in " << timer.elapsed() << " ms";
    return true;
}

bool PlayerController::waitStopPlay(const QString& file)
{
    m_stopPlayWaitingThread = std::make_unique<StopWaitingThread>(this, file.toStdString());
    m_stopPlayWaitingThread->setOnFinished([this]() {
        // 可根据需要添加额外处理
    });
    m_stopPlayWaitingThread->start();
    qCDebug(playerControllerLog) << "++++++++++ StopPlay waiting thread started";
    return true;
}

void PlayerController::allThreadStart()
{
    // 启动所有创建的线程
    if (m_packetReadThread) {
        m_packetReadThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Read packets thread started";
    }

    if (m_decodeVideoThread) {
        m_decodeVideoThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Video decode thread started";
    }

    if (m_decodeAudioThread) {
        m_decodeAudioThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Audio decode thread started";
    }

    if (m_decodeSubtitleThread) {
        m_decodeSubtitleThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Subtitle decode thread started";
    }

    if (m_videoPlayThread) {
        m_videoPlayThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Video play thread started";
    }

    if (m_audioPlayThread) {
        m_audioPlayThread->start();
        qCDebug(playerControllerLog) << "++++++++++ Audio play thread started";
    }

    // 通知UI更新
    emit setPlayControlWnd(true);
    emit updatePlayControlVolume();
    emit updatePlayControlStatus();
}

// 辅助函数
void PlayerController::videoSeekInc(double increment)
{
    if (!m_videoState)
        return;

    auto state = m_videoState->get_state();
    if (!state)
        return;

    double position = get_master_clock(state);
    if (std::isnan(position)) {
        position = static_cast<double>(state->seek_pos) / AV_TIME_BASE;
    }

    position += increment;
    videoSeek(position, increment);
}

// 新增自愈机制辅助函数
void PlayerController::checkAndResetState()
{
    std::lock_guard<std::mutex> lock(m_stopMutex);
    if (!m_packetReadThread && !m_decodeVideoThread && !m_decodeAudioThread && !m_audioPlayThread
        && !m_videoPlayThread && !m_decodeSubtitleThread) {
        m_videoState.reset();
        m_currentFile.clear();
        m_state = PlayerState::Idle;
        qCDebug(playerControllerLog)
            << "[PlayerController] All threads stopped, state reset to Idle.";
        emit playbackFinished(); // 新增：通知UI
    } else {
        qCDebug(playerControllerLog) << "[PlayerController] checkAndResetState: "
                                     << "m_packetReadThread:" << (bool) m_packetReadThread
                                     << "m_decodeVideoThread:" << (bool) m_decodeVideoThread
                                     << "m_decodeAudioThread:" << (bool) m_decodeAudioThread
                                     << "m_audioPlayThread:" << (bool) m_audioPlayThread
                                     << "m_videoPlayThread:" << (bool) m_videoPlayThread
                                     << "m_decodeSubtitleThread:" << (bool) m_decodeSubtitleThread;
    }
}

// 线程创建方法
bool PlayerController::createVideoState(const QString& file)
{
    const bool useHardware = false; // 待实现：来自UI设置
    const bool loop = false;        // 待实现：来自UI设置

    if (m_videoState)
        return false;

    m_videoState = std::make_unique<VideoStateData>(useHardware, loop);
    const int ret = m_videoState->create_video_state(file.toUtf8().constData());

    if (ret < 0) {
        m_videoState.reset();
        qCWarning(playerControllerLog) << "Video state creation failed (error: " << ret << ")";
        return false;
    }

    return true;
}

void PlayerController::deleteVideoState()
{
    m_videoState.reset();
}

bool PlayerController::createReadThread()
{
    if (m_packetReadThread)
        return false;
    m_packetReadThread = std::make_unique<ReadThread>(m_videoState ? m_videoState->get_state()
                                                                   : nullptr);
    m_packetReadThread->setOnFinished(
        [this]() { QMetaObject::invokeMethod(this, "readPacketStopped", Qt::QueuedConnection); });
    return true;
}

bool PlayerController::createDecodeVideoThread()
{
    if (!m_videoState || m_decodeVideoThread)
        return false;

    auto state = m_videoState->get_state();
    if (!state)
        return false;

    m_decodeVideoThread = std::make_unique<VideoDecodeThread>(state);
    m_decodeVideoThread->setOnFinished(
        [this]() { QMetaObject::invokeMethod(this, "decodeVideoStopped", Qt::QueuedConnection); });

    auto codecContext = m_videoState->get_contex(AVMEDIA_TYPE_VIDEO);

    // 初始化视频解码器
    int ret = decoder_init(&state->viddec,
                           codecContext,
                           &state->videoq,
                           state->continue_read_thread);
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Video decoder initialization failed (error: " << ret << ")";
        return false;
    }

    ret = decoder_start(&state->viddec, m_decodeVideoThread.get(), "video_decoder");
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Video decoder start failed (error: " << ret << ")";
        return false;
    }

    state->queue_attachments_req = 1;
    return true;
}

bool PlayerController::createDecodeAudioThread()
{
    if (!m_videoState || m_decodeAudioThread)
        return false;

    auto state = m_videoState->get_state();
    if (!state)
        return false;

    m_decodeAudioThread = std::make_unique<AudioDecodeThread>(state);
    m_decodeAudioThread->setOnFinished(
        [this]() { QMetaObject::invokeMethod(this, "decodeAudioStopped", Qt::QueuedConnection); });

    auto codecContext = m_videoState->get_contex(AVMEDIA_TYPE_AUDIO);

    // 初始化音频解码器
    int ret = decoder_init(&state->auddec,
                           codecContext,
                           &state->audioq,
                           state->continue_read_thread);
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Audio decoder initialization failed (error: " << ret << ")";
        return false;
    }

    ret = decoder_start(&state->auddec, m_decodeAudioThread.get(), "audio_decoder");
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Audio decoder start failed (error: " << ret << ")";
        return false;
    }

    return true;
}

bool PlayerController::createDecodeSubtitleThread()
{
    if (!m_videoState || m_decodeSubtitleThread)
        return false;

    auto state = m_videoState->get_state();
    if (!state)
        return false;

    m_decodeSubtitleThread = std::make_unique<SubtitleDecodeThread>(state);
    m_decodeSubtitleThread->setOnFinished([this]() {
        QMetaObject::invokeMethod(this, "decodeSubtitleStopped", Qt::QueuedConnection);
    });

    auto codecContext = m_videoState->get_contex(AVMEDIA_TYPE_SUBTITLE);

    // 初始化字幕解码器
    int ret = decoder_init(&state->subdec,
                           codecContext,
                           &state->subtitleq,
                           state->continue_read_thread);
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Subtitle decoder initialization failed (error: " << ret << ")";
        return false;
    }

    ret = decoder_start(&state->subdec, m_decodeSubtitleThread.get(), "subtitle_decoder");
    if (ret < 0) {
        qCWarning(playerControllerLog) << "Subtitle decoder start failed (error: " << ret << ")";
        return false;
    }

    return true;
}

bool PlayerController::createVideoPlayThread()
{
    if (!m_videoState || m_videoPlayThread)
        return false;

    auto state = m_videoState->get_state();
    if (!state)
        return false;

    m_videoPlayThread = std::make_unique<VideoPlayThread>(state);
    m_videoPlayThread->setOnFinished(
        [this]() { QMetaObject::invokeMethod(this, "videoPlayStopped", Qt::QueuedConnection); });
    m_videoPlayThread->setOnFrameReady([this](AVFrame* frame) { this->onFrameReady(frame); });
    m_videoPlayThread->setOnSubtitleReady([this](const QString& text) {
        // TODO: 实现 PlayerController::onSubtitleReady(const QString&) 处理字幕
        // onSubtitleReady(text);
    });

    // 初始化参数
    auto videoContext = m_videoState->get_contex(AVMEDIA_TYPE_VIDEO);
    const bool useHardware = m_videoState->is_hardware_decode();

    if (!m_videoPlayThread->init_resample_param(videoContext, useHardware)) {
        qCWarning(playerControllerLog) << "Video resample parameters initialization failed";
        return false;
    }

    return true;
}

bool PlayerController::createAudioPlayThread()
{
    if (!m_videoState || m_audioPlayThread)
        return false;

    auto state = m_videoState->get_state();
    if (!state)
        return false;

    m_audioPlayThread = std::make_unique<AudioPlayThread>(state);
    m_audioPlayThread->setOnFinished(
        [this]() { QMetaObject::invokeMethod(this, "audioPlayStopped", Qt::QueuedConnection); });
    m_audioPlayThread->setOnUpdatePlayTime([this]() {
        // TODO: 实现 PlayerController::onUpdatePlayTime() 处理播放时间更新
        // onUpdatePlayTime();
    });
    m_audioPlayThread->setOnDataVisualReady([this](const AudioData& data) {
        // TODO: 实现 PlayerController::onDataVisualReady(const AudioData&) 处理可视化数据
        // onDataVisualReady(data);
    });

    // 连接信号
    // connect(m_audioPlayThread.get(),
    //         &AudioPlayThread::update_play_time,
    //         this,
    //         &PlayerController::updatePlayTime);
    // connect(m_audioPlayThread.get(),
    //         &AudioPlayThread::data_visual_ready,
    //         this,
    //         &PlayerController::audioData);

    // 音频设备初始化在独立线程中完成
    return true;
}

bool PlayerController::startPlayThread()
{
    if (m_beforePlayThread)
        return false;

    m_beforePlayThread = std::make_unique<StartPlayThread>(this);
    m_beforePlayThread->setOnFinished([this]() {
        qCDebug(playerControllerLog) << "[StartPlayThread] finished, call playStarted()";
        playStarted();
    });
    m_beforePlayThread->start();
    qCDebug(playerControllerLog) << "++++++++++ StartPlay thread (audio init) started";

    return true;
}

// 调试辅助函数
void PlayerController::printDecodeContext(const AVCodecContext* codecCtx, bool isVideo) const
{
    if (!codecCtx)
        return;

    qCInfo(playerControllerLog) << (isVideo ? "Video" : "Audio") << " codec: " << codecCtx->codec->name;
    qCInfo(playerControllerLog) << "  Type:" << codecCtx->codec_type << "ID:" << codecCtx->codec_id << "Tag:" << codecCtx->codec_tag;

    if (isVideo) {
        qCInfo(playerControllerLog) << "  Dimensions: " << codecCtx->width << "x" << codecCtx->height;
    } else {
        qCInfo(playerControllerLog) << "  Sample rate: " << codecCtx->sample_rate << " Hz, Channels: " << codecCtx->ch_layout.nb_channels << ", Format: " << codecCtx->sample_fmt;
        qCInfo(playerControllerLog) << "  Frame size: " << codecCtx->frame_size << ", Block align: " << codecCtx->block_align;
    }
}

// 在合适位置实现 onFrameReady
void PlayerController::onFrameReady(AVFrame* frame)
{
    // 这里可以做帧处理、缓存、同步等操作
    emit frameReady(frame); // 直接转发给 UI 层
}