QTime t;
QIODevice ioDevice;
t.restart();
AVPacket *pkt = readPacket();
if (pkt->stream_index == videoIndex) { // 当前为视频帧，计算视频播放每帧的间隔时间（1000/fps） - 解码消耗的时间（毫秒） = 实际解码间隔时间interval
    codecPacket(pkt);int el = t.elapsed();int interval = 1000 / fps - el > 0 ? 1000 / fps - el : 1;QThread::msleep(interval);
}
else if (pkt->stream_index == audioIndex) { // 当前为音频帧，直接让Qt的音频播放器播放
    codecPacket(pkt);char data[10000] = { 0 };int len = toPCM(data);ioDevice->write(data, len);
}

AVPacket *pkt = readPacket();if (pkt->stream_index == audioIndex) {codecPacket(pkt);char data[AUDIO_IODEVICE_WRITE_SIZE] = { 0 };int len = toPCM(data);ioDevice->write(data, len);
}
else if (pkt->stream_index == videoIndex) {videoPacketList.push_back(pkt);
}while (videoPacketList.size() > 0 && videoPts < audioPts) {AVPacket *pkt = videoPacketList.front();videoPacketList.pop_front();codecPacket(pkt);
}

AVRational r;
frame->pts * (double)r.num / (double)r.den;

class Decoder : protected QThread
{
public:Decoder();virtual ~Decoder();bool open(const char *filename);void close();// 从文件中读取一个压缩报文AVPacket* readPacket();// 解码报文并释放空间，返回值为当前解码报文的pts时间（毫秒）int codecPacket(AVPacket* pkt);// 将解码帧Frame转码为RGB或PCMint toRGB(char *outData, int outWidth, int outHeight);int toPCM(char *outData);int durationMsec; // 文件时长int fps; // 视频FPSint srcWidth; // 视频宽度int srcHeight; // 视频高度int videoIndex; // 视频通道int audioIndex; // 音频通道int sampleRate; // 音频采样率int channels; // 声道int sampleSize; // 样本位数bool endFlag; // 线程结束标志bool pauseFlag; // 线程暂停标志// 记录当前的音视频所处在的pts时间戳（毫秒）int videoPts;int audioPts;// 记录音视频的编解码格式int sampleFmt;int pixFmt;/************************************************************************//* default: CD音质（16bit 44100Hz stereo）                              *//************************************************************************/int dstSampleRate = 44100; // 采样率int dstSampleSize = 16; // 采样大小int dstChannels = 2; // 通道数// 线程启动的代理方法void start();// 音频输出QAudioOutput *audioOutput = NULL;
protected:void run();
private:QMutex mtx;AVFormatContext *pFormatCtx = NULL;SwsContext *videoSwsCtx = NULL;AVFrame *yuv = NULL;SwrContext *audioSwrCtx = NULL;AVFrame *pcm = NULL;QIODevice *ioDevice = NULL;std::list<AVPacket*> videoPacketList;AVInputTypeEnum avType = AVInputTypeEnum::NOTYPE;QString fileName;
};

class PlayerWidget : public QOpenGLWidget
{
public:PlayerWidget(Decoder *dec, QWidget *parent, int interval);virtual ~PlayerWidget();/************************************************************************//* default: 720p 25fps                                                  *//************************************************************************/int videoWidth = 720;int videoHeight = 480;int m_interval = 40;/************************************************************************//* default: CD音质（16bit 44100Hz stereo）                              *//************************************************************************/int sampleRate = 44100; // 采样率int sampleSize = 16; // 采样大小int channels = 2; // 通道数
protected:void timerEvent(QTimerEvent *e);void paintEvent(QPaintEvent *e);
private:Decoder *decoder = NULL;QAudioOutput *out;QIODevice *io;
};

struct AspectRatio {double width;double height;
};static AspectRatio* fitRatio(int outWidth, int outHeight, int inWidth, int inHeight) {double r1 = ((double)outWidth / (double)outHeight);double r2 = ((double)inWidth / (double)inHeight);AspectRatio *ar = new AspectRatio;if (r1 > r2) {int newWidth = (double)(outHeight * inWidth) / (double)inHeight;ar->width = newWidth;ar->height = outHeight;return ar;}else {int newHeight = (double)(inHeight * outWidth) / (double)inWidth;ar->width = outWidth;ar->height = newHeight;return ar;}
}