临时显示出图像，延迟大，cpu占用太高

src/convert.cpp

@@ -72,8 +72,7 @@ bool Convert::convert(AVFrame* srcFrame, AVFrame* dstFrame)
     if(!m_convertCtx || !srcFrame || !dstFrame) {
         return false;
     }
-    qint32 ret = sws_scale(m_convertCtx, (const uint8_t* const*)srcFrame->data, srcFrame->linesize, 0, m_srcHeight, dstFrame->data, dstFrame->linesize);
-    qDebug() << "Convert::convert sws_scale return " << ret;
+    qint32 ret = sws_scale(m_convertCtx, (const uint8_t* const*)srcFrame->data, srcFrame->linesize, 0, m_srcHeight, dstFrame->data, dstFrame->linesize);    
     if (0 == ret) {
         return false;
     }

src/convert.h

@@ -4,6 +4,7 @@
 
 extern "C"
 {
+#include "libavcodec/avcodec.h"
 #include "libswscale/swscale.h"
 #include "libavutil/frame.h"
 }

src/decoder.cpp

@@ -93,6 +93,7 @@ void Decoder::run()
     AVFrame* rgbDecoderFrame = Q_NULLPTR;
     yuvDecoderFrame = av_frame_alloc();
     rgbDecoderFrame = av_frame_alloc();
+    quint8 *outBuffer = Q_NULLPTR;
 
     bool isFormatCtxOpen = false;
     bool isCodecCtxOpen = false;
@@ -164,12 +165,19 @@ void Decoder::run()
         if (!ret) {
             // a frame was received
             if (!m_conver.isInit()) {
+                qDebug() << "decoder frame format" << yuvDecoderFrame->format;
                 m_conver.setSrcFrameInfo(codecCtx->width, codecCtx->height, AV_PIX_FMT_YUV420P);
-                m_conver.setDstFrameInfo(codecCtx->width, codecCtx->height, AV_PIX_FMT_RGB24);
+                m_conver.setDstFrameInfo(codecCtx->width, codecCtx->height, AV_PIX_FMT_RGB32);
                 m_conver.init();
             }
+            if (!outBuffer) {
+                outBuffer=new quint8[avpicture_get_size(AV_PIX_FMT_RGB32, codecCtx->width, codecCtx->height)];
+                avpicture_fill((AVPicture *)rgbDecoderFrame, outBuffer, AV_PIX_FMT_RGB32, codecCtx->width, codecCtx->height);
+            }
             m_conver.convert(yuvDecoderFrame, rgbDecoderFrame);
-            //push_frame(decoder);
+            QImage tmpImg((uchar *)outBuffer, codecCtx->width, codecCtx->height, QImage::Format_RGB32);
+            QImage image = tmpImg.copy(); //把图像复制一份 传递给界面显示
+            emit getOneImage(image);
         } else if (ret != AVERROR(EAGAIN)) {
             qCritical("Could not receive video frame: %d", ret);
             av_packet_unref(&packet);
@@ -215,6 +223,9 @@ runQuit:
             avcodec_free_context(&codecCtx);
         }
 
+        if (outBuffer) {
+            delete[] outBuffer;
+        }
         if (yuvDecoderFrame) {
          av_free(yuvDecoderFrame);
         }

src/decoder.h

@@ -4,6 +4,7 @@
 #include <QThread>
 #include <QTcpSocket>
 #include <QPointer>
+#include <QImage>
 
 #include "convert.h"
 extern "C"
@@ -28,6 +29,8 @@ public:
     bool startDecode();
     void stopDecode();
 
+signals:
+    void getOneImage(QImage img);
 protected:
     void run();
 

src/dialog.cpp

@@ -23,6 +23,14 @@ Dialog::Dialog(QWidget *parent) :
             decoder.startDecode();
         }
     });
+
+    // must be Qt::QueuedConnection, ui update must be main thread
+    connect(&decoder, &Decoder::getOneImage, this, [this](QImage img){
+        // 将图像按比例缩放成和窗口一样大小
+        QImage img2 = img.scaled(ui->imgLabel->size(), Qt::IgnoreAspectRatio);
+        ui->imgLabel->setPixmap(QPixmap::fromImage(img2));
+        qDebug() << "getOneImage";
+    }, Qt::QueuedConnection);
 }
 
 Dialog::~Dialog()

src/dialog.ui

@@ -6,8 +6,8 @@
    <rect>
     <x>0</x>
     <y>0</y>
-    <width>400</width>
-    <height>300</height>
+    <width>716</width>
+    <height>757</height>
    </rect>
   </property>
   <property name="windowTitle">
@@ -52,6 +52,22 @@
     <string>stopServer</string>
    </property>
   </widget>
+  <widget class="QLabel" name="imgLabel">
+   <property name="geometry">
+    <rect>
+     <x>230</x>
+     <y>20</y>
+     <width>451</width>
+     <height>701</height>
+    </rect>
+   </property>
+   <property name="styleSheet">
+    <string notr="true">background-color: rgb(0, 0, 0);</string>
+   </property>
+   <property name="text">
+    <string/>
+   </property>
+  </widget>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <resources/>