#ifndef IMAGE_PROCESSOR_H
#define IMAGE_PROCESSOR_H#include <QObject>
#include <QImage>
#include <QByteArray>extern "C" {
#include <libavformat/avformat.h>
#include <libavcodec/avcodec.h>
#include <libswscale/swscale.h>
}class ImageProcessor : public QObject
{Q_OBJECT
public:explicit ImageProcessor(QObject *parent = nullptr);~ImageProcessor();void processImage(const QByteArray& imageData, QImage& image);signals:void imageProcessed(const QImage &image);private:AVCodec *decoder;AVCodecContext *decoderContext;SwsContext *swsContext;
};#endif // IMAGE_PROCESSOR_H #include "image_processor.h"
#include <QDebug>
ImageProcessor::ImageProcessor(QObject *parent) : QObject(parent)
{av_register_all();avcodec_register_all();decoder = avcodec_find_decoder(AV_CODEC_ID_MJPEG);if (!decoder) {qDebug() << "Could not find decoder";return;}decoderContext = avcodec_alloc_context3(decoder);if (!decoderContext) {qDebug() << "Could not allocate codec context";return;}if (avcodec_open2(decoderContext, decoder, nullptr) < 0) {qDebug() << "Could not open codec";return;}
}ImageProcessor::~ImageProcessor()
{if (decoderContext) {avcodec_free_context(&decoderContext);}if (swsContext) {sws_freeContext(swsContext);}
}void ImageProcessor::processImage(const QByteArray &imageData, QImage& image)
{AVPacket packet;av_init_packet(&packet);packet.data = reinterpret_cast<uint8_t*>(const_cast<char*>(imageData.data()));packet.size = imageData.size();AVFrame *frame = av_frame_alloc();if (!frame) {qDebug() << "Could not allocate frame";return;}if (avcodec_send_packet(decoderContext, &packet) < 0) {qDebug() << "Error sending packet to decoder";av_frame_free(&frame);return;}if (avcodec_receive_frame(decoderContext, frame) < 0) {qDebug() << "Error receiving frame from decoder";av_frame_free(&frame);return;}int newWidth = decoderContext->width;int newHeight = decoderContext->height;swsContext = sws_getContext(decoderContext->width, decoderContext->height, decoderContext->pix_fmt,newWidth, newHeight, AV_PIX_FMT_RGB24,SWS_BILINEAR, nullptr, nullptr, nullptr);if (!swsContext) {qDebug() << "Could not allocate sws context";av_frame_free(&frame);return;}AVFrame *outputFrame = av_frame_alloc();if (!outputFrame) {qDebug() << "Could not allocate output frame";sws_freeContext(swsContext);av_frame_free(&frame);return;}outputFrame->format = AV_PIX_FMT_RGB24;outputFrame->width = newWidth;outputFrame->height = newHeight;if (av_frame_get_buffer(outputFrame, 0) < 0) {qDebug() << "Could not allocate output frame buffer";sws_freeContext(swsContext);av_frame_free(&outputFrame);av_frame_free(&frame);return;}sws_scale(swsContext, frame->data, frame->linesize, 0, decoderContext->height,outputFrame->data, outputFrame->linesize);QImage img(newWidth, newHeight, QImage::Format_RGB888);for (int y = 0; y < newHeight; ++y) {memcpy(img.scanLine(y), outputFrame->data[0] + y * outputFrame->linesize[0], newWidth * 3);}emit imageProcessed(img);sws_freeContext(swsContext);av_frame_free(&outputFrame);av_frame_free(&frame);img.swap(image);
} 在做网络投屏时，遇到接收数据后在加载到QImage时，时不时的就会出现加载图片失败，导致实时投屏显示花屏、闪烁，就行借用了ffmpeg 对图片数据的处理能力。处理好后绘制到QT界面上。
