FFmpeg——Windows下，视频播放器3：绘制画面、缩放、暂停、拖拽进度条

#include "XFFmpeg.h"

#pragma comment(lib, "avformat.lib")
#pragma comment(lib, "avutil.lib")
#pragma comment(lib, "avcodec.lib")
#pragma comment(lib, "swscale.lib")

static double r2d(AVRational r)
{
    return r.num == 0 || r.den == 0 ? 0. : (double)r.num / (double)r.den;
}

int XFFmpeg::Open(const char *path)
{
    Close();

    mutex.lock();       //考虑多线程, 尽量晚的锁,尽量早的释放
    /*char *path = "video.mp4";*/

    int re = avformat_open_input(&ic, path, 0, 0);  // lib: avformat
    if (re != 0)
    {
        mutex.unlock();
        av_strerror(re, errorbuf, sizeof(errorbuf));    // lib: avutil
        printf("open %s failed: %s\n", path, errorbuf);
        return 0;
    }
    totalMs = ((ic->duration / AV_TIME_BASE) * 1000);

    //找到解码器, 打开解码器
    for (int i = 0; i < ic->nb_streams; i++)
    {
        //AVCodecContext: 解码器的值
        AVCodecContext *enc = ic->streams[i]->codec;
        if (enc->codec_type == AVMEDIA_TYPE_VIDEO)
        {
            videoStream = i;                //记录视频流index
            fps = r2d(ic->streams[i]->avg_frame_rate);

            AVCodec *codec = avcodec_find_decoder(enc->codec_id);
            if (!codec)
            {
                mutex.unlock();
                printf("video code not find! \n");  
                return 0;
            }

            //打开解码器
            int err = avcodec_open2(enc, codec, NULL);
            if (err != 0)
            {
                mutex.unlock();
                char buf[1024] = { 0 };
                av_strerror(err, buf, sizeof(buf));
                printf(buf);
                return 0;
            }
            printf("open codec success!\n");
        }
    }
    mutex.unlock();
    return totalMs;
}

void XFFmpeg::Close()
{
    mutex.lock();
    if (ic) avformat_close_input(&ic);
    if (yuv) av_frame_free(&yuv);
    if (cCtx)
    {
        sws_freeContext(cCtx);
        cCtx = NULL;
    }
    mutex.unlock();
}

std::string XFFmpeg::GetError()
{
    mutex.lock();
    std::string re = this->errorbuf;    //返回出去的是一份复制的空间,不会造成多线程访问出现异常
    mutex.unlock();
    return re;
}//多线程安全, 复制一份

AVPacket XFFmpeg::Read()
{
    AVPacket pkt;
    memset(&pkt, 0, sizeof(AVPacket));
    mutex.lock();
    if (!ic)
    {
        mutex.unlock();
        return pkt;
    }
    int err = av_read_frame(ic, &pkt);
    if (err != 0)
    {
        av_strerror(err, errorbuf, sizeof(errorbuf));
    }
    mutex.unlock();
    if (pkt.size != 0)
    {
        int pts = pkt.pts * r2d(ic->streams[pkt.stream_index]->time_base) * 1000;
        printf("pts = %d \n", pts);
    }
    return pkt;
}

AVFrame *XFFmpeg::Decode(const AVPacket *pkt)
{
    mutex.lock();
    if (!ic)
    {
        mutex.unlock();
        return NULL;
    }

    if (yuv == NULL)
    {
        yuv = av_frame_alloc();
    }

    int re = avcodec_send_packet(ic->streams[pkt->stream_index]->codec, pkt);
    if (re != 0)
    {
        mutex.unlock();
        return NULL;
    }

    re = avcodec_receive_frame(ic->streams[pkt->stream_index]->codec, yuv);
    if (re != 0)
    {
        mutex.unlock();
        return NULL;
    }

    mutex.unlock();

在解码一帧后，获取yuv的显示时间戳pts

    pts = (yuv->pts * r2d(ic->streams[pkt->stream_index]->time_base)) * 1000;   //得到毫秒数
    return yuv;
}

拖动进度条，将拖拽点的位置按照比例换算成显示时间戳pts，清空视频缓存.

bool XFFmpeg::Seek(float pos)
{
    mutex.lock();
    if (!ic)
    {
        mutex.unlock();
        return false;
    }
    int64_t stamp = 0;  //存放时间戳
    stamp = pos * ic->streams[videoStream]->duration;       //实际要seek的位置
    int re = av_seek_frame(ic, 
        videoStream, 
        stamp,
        AVSEEK_FLAG_BACKWARD | AVSEEK_FLAG_FRAME);          //关键帧

    avcodec_flush_buffers(ic->streams[videoStream]->codec); //释放刚刚解码完的数据(seek之前)

    pts = stamp * r2d(ic->streams[videoStream]->time_base) * 1000;  //得到毫秒数
    mutex.unlock();
    if (re > 0)
        return false;

    return true;
}

bool XFFmpeg::ToGRB(char *out, int outwidth, int outheight)
{
    mutex.lock();
    if (!ic || !yuv)
    {
        mutex.unlock();
        return NULL;
    }

    AVCodecContext *videoCtx = ic->streams[this->videoStream]->codec;
    cCtx = sws_getCachedContext(cCtx, videoCtx->width,
        videoCtx->height,
        videoCtx->pix_fmt,      //源参数       解码之后视频帧, 存的是什么格式, 现在我们还没有解码 (1.可以直接写死, 但通用性低.  2.解码一次以上再调用这段代码)
        outwidth,
        outheight,
        AV_PIX_FMT_BGRA,
        SWS_BICUBIC,            //转码用什么算法
        NULL, NULL, NULL
        );
    if (!cCtx)
    {
        mutex.unlock();
        //printf("sws_gegCachedContext success!\n");
        printf("sws_gegCachedContext failed!\n");
        return false;
    }

    uint8_t *data[AV_NUM_DATA_POINTERS] = { 0 };
    data[0] = (uint8_t *)out;
    int linesize[AV_NUM_DATA_POINTERS] = { 0 };
    linesize[0] = outwidth * 4;     //一行的大小, 宽 * 4
    int h = sws_scale(cCtx, yuv->data, yuv->linesize, 0, videoCtx->height,  //返回转码后的高度
        data,
        linesize);

    if (h > 0)
    {
        printf("(h:%d) ", h);
    }

    mutex.unlock();
    return true;
}

XFFmpeg::XFFmpeg()
{
    errorbuf[0] = '\0';
    av_register_all();
}


XFFmpeg::~XFFmpeg()
{
}

绘制画面

重写QOpenGLWidget的draw方法，利用GPU定时刷新界面.

#include "VideoWidget.h"
#include 
#include "XFFmpeg.h"
#include "XVideoThread.h"

VideoWidget::VideoWidget(QWidget *p) : QOpenGLWidget(p)
{
    startTimer(20);
    XVideoThread::Get()->start();
}


VideoWidget::~VideoWidget()
{
}

void VideoWidget::paintEvent(QPaintEvent *e)
{
    static QImage *image = NULL;
    static int w = 0;
    static int h = 0;

缩放

记录上一次的宽高，对比宽高. 若宽高改变，丢弃画面，再绘制画面。

    if (w != width() || h != height())
    {
        if (image)
        {
            delete image->bits();
            delete image;
            image = NULL;
        }
    }

    if (image == NULL)
    {
        uchar *buf = new uchar[width() * height() * 4];
        image = new QImage(buf, width(), height(), QImage::Format_ARGB32);
    }

    XFFmpeg::Get()->ToGRB((char*)image->bits(), width(), height());

    QPainter painter;

    painter.begin(this);
    painter.drawImage(QPoint(0, 0), *image);
    painter.end();
}

void VideoWidget::timerEvent(QTimerEvent *e)
{
    this->update();     
}

#include "czyplayer.h"
#include 
#include "XFFmpeg.h"
#include 

static bool isPressSlider = false;
static bool isPlay = true;

显示播放时间

CzyPlayer::CzyPlayer(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    startTimer(100);
}

void CzyPlayer::timerEvent(QTimerEvent *e)
{
    int min = (XFFmpeg::Get()->pts / 1000) / 60;
    int sec = (XFFmpeg::Get()->pts / 1000) % 60;

    char buf[1024] = { 0 };

    sprintf(buf, "%02d:%02d", min, sec);

    ui.playtime->setText(buf);

    if (XFFmpeg::Get()->totalMs > 0)
    {
        float rate = (float)XFFmpeg::Get()->pts / (float)XFFmpeg::Get()->totalMs;
        if (!isPressSlider) //按下的时候不显示
            ui.playSlider->setValue(rate * 1000);
    }
}

void CzyPlayer::resizeEvent(QResizeEvent *e)
{
    ui.openGLWidget->resize(size());
    ui.playButton->move(10, this->height() - 46);
    ui.openButton->move(this->width() - 60, this->height() - 48);
    ui.playtime->move(64, this->height() - 40);
    ui.totaltime->move(this->width() - 110, this->height() - 40);
    ui.playSlider->move(114, this->height() - 34);
    ui.playSlider->resize(this->width() - 240, ui.playSlider->height());

}

拖动进度条

void CzyPlayer::sliderPress()
{
    isPressSlider = true;
}


void CzyPlayer::sliderRelease()
{
    isPressSlider = false;
    float pos = 0;
    pos = (float)ui.playSlider->value() / (float)(ui.playSlider->maximum() + 1);
    XFFmpeg::Get()->Seek(pos);
}

播放、暂停切换

void CzyPlayer::play()
{
    //border-image: url(:/CzyPlayer/Resources/play_normal.png);
    isPlay = !isPlay;
    XFFmpeg::Get()->isPlay = isPlay;
    if (isPlay)
    {
        ui.playButton->setStyleSheet("border-image: url(:/CzyPlayer/Resources/pause_normal.png)");
    }
    else
    {
        ui.playButton->setStyleSheet("border-image: url(:/CzyPlayer/Resources/play_normal.png)");
    }
}

void CzyPlayer::open()      
{
    QString name = QFileDialog::getOpenFileName(
        this,
        QString::fromLocal8Bit("选择视频文件"));

    if (name.isEmpty())
    {
        return;
    }

    this->setWindowTitle(name);
    int totalMs = XFFmpeg::Get()->Open(name.toLocal8Bit());
    if (totalMs <=0)
    {
        QMessageBox::information(this, "err", "file open failed!");
        return;
    }

    int min = (totalMs / 1000) / 60;
    int sec = (totalMs / 1000) % 60;
    char buf[1024] = { 0 };

    sprintf(buf, "%02d:%02d", min, sec);

    ui.totaltime->setText(buf);

    isPlay = false;
    play();

}


CzyPlayer::~CzyPlayer()
{

}

程序运行结果

源码下载  密码:6hsp