ffmpeg_0">Qt使用ffmpeg获取视频文件封面图

#ifndef __THUM_HELPER_H_
#define __THUM_HELPER_H_

extern "C" {
#include "libavformat/avformat.h"
#include "libavutil/imgutils.h"
#include "libswscale/swscale.h"
}
#include <QObject>
#include <QImage>
namespace Media {

	class ThumHelper :public QObject
	{
		Q_OBJECT
	public:
		ThumHelper();
		~ThumHelper();
		void initGlobal();
		QImage thumnail(const QString& videoPath);
	};
}

#endif  //__THUM_HELPER_H_

#include "ThumHelper.h"



Media::ThumHelper::ThumHelper()
{
	initGlobal();
}

void Media::ThumHelper::initGlobal()
{
	av_register_all();
}

QImage Media::ThumHelper::thumnail(const QString& videoPath)
{

	QImage image;
	AVFormatContext * fmtContext = nullptr;
	if (avformat_open_input(&fmtContext, videoPath.toStdString().c_str(), nullptr, nullptr) < 0) {
		return image;
	}
	if (avformat_find_stream_info(fmtContext, nullptr) < 0) {
		avformat_close_input(&fmtContext);
		return image;
	}
	int nStreamIndex = -1;
	AVCodecParameters *codecParameters = nullptr;
	for (int i = 0; i < fmtContext->nb_streams; i++) {
		if (fmtContext->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
			nStreamIndex = i;
			codecParameters = fmtContext->streams[i]->codecpar;
			break;
		}
	}
	if (nStreamIndex == -1) {
		avformat_close_input(&fmtContext);
		return image;
	}
	AVCodec* codec = avcodec_find_decoder(codecParameters->codec_id);

	if (!codec) {
		avformat_close_input(&fmtContext);
		return image;
	}
	AVCodecContext* codecContext = avcodec_alloc_context3(codec);
	if (!codecContext) {
		// 分配解码器上下文失败
		avformat_close_input(&fmtContext);
		return image;
	}
	if (avcodec_parameters_to_context(codecContext, codecParameters) < 0) {
		// 复制解码器参数到解码器上下文失败
		avcodec_free_context(&codecContext);
		avformat_close_input(&fmtContext);
		return image;
	}
	if (avcodec_open2(codecContext, codec, nullptr) < 0) {
		// 打开解码器失败
		avcodec_free_context(&codecContext);
		avformat_close_input(&fmtContext);
		return image;
	}
	AVPacket packet;
	av_init_packet(&packet);
	packet.data = nullptr;
	packet.size = 0;

	while (av_read_frame(fmtContext, &packet) >= 0) {
		if (packet.stream_index == nStreamIndex) {
			AVFrame* frame = av_frame_alloc();
			if (frame) {
				int ret = avcodec_send_packet(codecContext, &packet);
				if (ret >= 0) {
					ret = avcodec_receive_frame(codecContext, frame);
					if (ret >= 0) {
						// 将第一帧保存为封面图像
						if (frame->key_frame) {
							AVFrame* rgbFrame = av_frame_alloc();
							if (rgbFrame) {
								rgbFrame->format = AV_PIX_FMT_RGB24;
								rgbFrame->width = frame->width;
								rgbFrame->height = frame->height;

								int bufferSize = av_image_get_buffer_size(AV_PIX_FMT_RGB24, frame->width, frame->height, 1);
								uint8_t* buffer = new uint8_t[bufferSize];
								av_image_fill_arrays(rgbFrame->data, rgbFrame->linesize, buffer, AV_PIX_FMT_RGB24, frame->width, frame->height, 1);

								SwsContext* swsContext = sws_getContext(frame->width, frame->height, codecContext->pix_fmt,
									frame->width, frame->height, AV_PIX_FMT_RGB24, SWS_BICUBIC, nullptr, nullptr, nullptr);
								if (swsContext) {
									sws_scale(swsContext, frame->data, frame->linesize, 0, frame->height, rgbFrame->data, rgbFrame->linesize);
									sws_freeContext(swsContext);

									// 保存封面图像到文件
										int outputBufferSize = rgbFrame->width * rgbFrame->height * 3;
										uchar* outputBuffer = new uchar[outputBufferSize];

										for (int i = 0; i < rgbFrame->height; i++) {
											memcpy(outputBuffer + i * rgbFrame->width * 3, rgbFrame->data[0] + i * rgbFrame->linesize[0], rgbFrame->width * 3);
										}
										image = QImage(outputBuffer, rgbFrame->width, rgbFrame->height, QImage::Format_RGB888).copy();
										if (outputBuffer) {
											delete [] outputBuffer;
											outputBuffer = nullptr;
										}


									}
								
								if (buffer) {
									delete[] buffer;
									buffer = nullptr;
								}
								
								av_frame_free(&rgbFrame);
							}
						}
					}
				}

				av_frame_free(&frame);
			}
			break;
		}

		av_packet_unref(&packet);
	}

	avcodec_free_context(&codecContext);
	avformat_close_input(&fmtContext);
	return image;

}

Media::ThumHelper::~ThumHelper()
{

}

调用demo

#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QPushButton>
#include <QListWidget>

class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = 0);
    ~Widget();
	


private:
	QPushButton* m_loadVideo = nullptr;
	QListWidget *m_imageList;
};

#endif // WIDGET_H

#include "widget.h"
#include "ThumHelper.h"
#include <QVBoxLayout>
#include <QFileDialog>
#include <QPixmap>
#include <QLabel>
#include <QDebug>
#include <QDateTime>
Widget::Widget(QWidget *parent)
    : QWidget(parent)
{
	QVBoxLayout  *layout = new QVBoxLayout;

	m_loadVideo = new QPushButton(this);
	m_loadVideo->setText("Load Image");
	m_imageList = new QListWidget;
	layout->addWidget(m_loadVideo);
	layout->addWidget(m_imageList);
	this->setLayout(layout);
	connect(m_loadVideo, &QPushButton::clicked, [&]() {
		QStringList paths = QFileDialog::getOpenFileNames(nullptr, QString("Open File"), "",tr("Videos(*.mp4 *.irgd)"));
		Media::ThumHelper  helper;
		QDateTime dateTime = QDateTime::currentDateTime();
		qDebug() << "Begin Load:" << QDateTime::currentDateTime().toString("yyyy-mm-DD-hh-MM-ss");

		for (int i = 0; i < paths.count(); i++) {
			QString videoPath = paths.at(i);
			
			QListWidgetItem*  item = new QListWidgetItem(m_imageList);
			QImage image = helper.thumnail(videoPath);
			item->setSizeHint(QSize(image.width() / 4, image.height() / 4));
			QLabel* label = new QLabel(m_imageList);
			label->setPixmap(QPixmap::fromImage(image).scaled(image.width()/4, image.height()/4));
			m_imageList->addItem(item);
			m_imageList->setItemWidget(item, label);
		}
		qDebug() << "finish Load:" << QDateTime::currentDateTime().toString("yyyy-mm-DD-hh-MM-ss");
	});
}

Widget::~Widget()
{

}

#-------------------------------------------------
#
# Project created by QtCreator 2023-12-21T13:13:56
#
#-------------------------------------------------

QT       += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = Media
TEMPLATE = app

# The following define makes your compiler emit warnings if you use
# any feature of Qt which as been marked as deprecated (the exact warnings
# depend on your compiler). Please consult the documentation of the
# deprecated API in order to know how to port your code away from it.
DEFINES += QT_DEPRECATED_WARNINGS

# You can also make your code fail to compile if you use deprecated APIs.
# In order to do so, uncomment the following line.
# You can also select to disable deprecated APIs only up to a certain version of Qt.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0


SOURCES += main.cpp\
        widget.cpp

HEADERS  += widget.h




INCLUDEPATH +=$$PWD/ffmpeg/4.2.1/include

message($$PWD/ffmpeg/4.2.1/include)

win32{
    CONFIG(debug,debug|release){
        LIBS+= -L$$PWD/ffmpeg/4.2.1/x64/lib
        message($$PWD/ffmpeg/4.2.1/x64/lib)

    }
}


LIBS+= -lavcodec \
       -lavfilter \
       -lavformat \
       -lswresample \
       -lswscale \
       -lpostproc \
       -lavutil \
       -lavdevice