linux+QT+FFmpeg 6.0,把多个QImage组合成一个视频

RecordingThread.h

#ifndef RECORDINGTHREAD_H
#define RECORDINGTHREAD_H
#include "QTimer"
#include <QObject>
#include <QImage>
#include <QQueue>

extern "C"{
    //因为FFmpeg是c语言,QT里面调用的话需要extern "C"
    #include "libavcodec/avcodec.h"
    #include "libavformat/avformat.h"
    #include "libswscale/swscale.h"
    #include "libavdevice/avdevice.h"
    #include "libavformat/avio.h"
    #include "libavutil/imgutils.h"
}

class RecordingThread : public QObject
{
    Q_OBJECT

public:
    void FFmpegInit();
    void saveMp4(QImage image);
    void stopMp4();

    void setImage(QImage image);


public slots:
    void recordInit();

signals:
    void send(QString);


private:
    AVFormatContext* formatContext;
    AVCodecParameters* codecParameters;
    const AVCodec* codec;
    AVCodecContext* codecContext;
    AVStream* stream;
    const AVPixelFormat* pixFmt;

    int num = 0;

    QQueue<QImage> gQdata;

    int isRecord = -1;

};

#endif // RECORDINGTHREAD_H

#include "recordingthread.h"
#include <QPainter>
#include <cmath>
#include <QPainterPath>
#include <QDebug>
#include <QTimer>
#include <QDateTime>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>


void RecordingThread::FFmpegInit(){
	isRecord = -1;
    int ret;
    // 初始化 FFmpeg
    qDebug()<<"avdevice_register_all()";
    avdevice_register_all(); //初始化所有设备
    qDebug()<<"formatContext = avformat_alloc_context()";
    formatContext = avformat_alloc_context();//分配format上下文

    qint64 timeT = QDateTime::currentMSecsSinceEpoch();//毫秒级时间戳
    QString outputFileName = QString("/sdcard/").append("ffmpeg").append(QString::number(timeT)).append(".mp4");
    //第三个参数可以直接使用nullptr 根据outputFileName的后缀自动识别
    qDebug()<<"avformat_alloc_output_context2(&formatContext, nullptr, \"mp4\", outputFileName.toUtf8().constData())";
    ret = avformat_alloc_output_context2(&formatContext, nullptr, nullptr, outputFileName.toUtf8().constData());
    qDebug()<<"ret===="<<ret;
    qDebug()<<"formatContext===="<<formatContext;
    qDebug()<<"formatContext->oformat = av_guess_format(nullptr, outputFileName.toUtf8().constData(), nullptr);";
    formatContext->oformat = av_guess_format(nullptr, outputFileName.toUtf8().constData(), nullptr);
    qDebug() << "avio_open(&formatContext->pb, outputFileName.toUtf8().constData(), AVIO_FLAG_WRITE) < 0";
    // 打开输出文件
    if (avio_open(&formatContext->pb, outputFileName.toUtf8().constData(), AVIO_FLAG_WRITE) < 0) {
        qDebug() << "Failed to open output file";
        return;
    }
    qDebug() << "AVStream* stream = avformat_new_stream(formatContext, nullptr);";
    // 创建一个AVStream对象
    stream = avformat_new_stream(formatContext, nullptr);
    if (!stream) {
        qDebug() << "Failed to create output stream";
        return;
    }

    qDebug() << "AVCodecParameters* codecParameters = stream->codecpar;";
     // 配置AVCodecContext
    codecParameters = stream->codecpar;
    codecParameters->codec_type = AVMEDIA_TYPE_VIDEO;
    codecParameters->codec_id = AV_CODEC_ID_H264; // 使用H.264编码器
    codecParameters->width = 400;
    codecParameters->height = 400;
	
	
	
    qDebug() << " const AVCodec* codec = avcodec_find_encoder(codecParameters->codec_id);";
     // 打开编解码器
    codec = avcodec_find_encoder(codecParameters->codec_id);
    codecContext = avcodec_alloc_context3(codec);
    codecContext->width = 400;
    codecContext->height = 400;
    codecContext->pix_fmt = AV_PIX_FMT_YUV420P;
    codecContext->time_base = {1, 25}; // 设置编码器的时间基为 1秒/30帧
    codecContext->framerate = {25, 1}; // 设置编码器的帧率为 30fps
	
	//codecContext->thread_count = 4;
	

    qDebug() << "AV_PIX_FMT_YUV420P====="<<AV_PIX_FMT_YUV420P;
    qDebug() << "codecContext->pix_fmt====="<<codecContext->pix_fmt;
    qDebug() << "avcodec_open2(codecContext, codec, nullptr);";
    //设置完成编码格式以后要立刻打开,要不然调用avcodec_parameters_to_context的时候会重置编码
    ret = avcodec_open2(codecContext, codec, nullptr);
    if(ret < 0){
         qDebug() << "Failed to avcodec_open2";
         return;
    }
    qDebug() << "avcodec_parameters_to_context(codecContext, codecParameters);";
    // 将编码器参数复制到输出流
    avcodec_parameters_to_context(codecContext, codecParameters);
    // 检查编解码器支持的像素格式
    pixFmt = codec->pix_fmts;
    qDebug() << "while";
    while (*pixFmt != AV_PIX_FMT_NONE) {
        qDebug() << av_get_pix_fmt_name(*pixFmt);
        ++pixFmt;
    }
    qDebug() << " avformat_write_header(formatContext, nullptr);";
    // 写入头部信息
    avformat_write_header(formatContext, nullptr);
}
void RecordingThread::saveMp4(QImage image){
    int imagewidth = image.width();
    int imageheight = image.height();
    int ret;
    //qDebug() << "  AVFrame* frame = av_frame_alloc();";
    // 逐个写入图像帧
    AVFrame* frame = av_frame_alloc();
    if (!frame) {
        qDebug() << "Failed to allocate frame.";
        return;
    }


    //qDebug() << "frame->format = AV_PIX_FMT_YUV420P";
    frame->format = AV_PIX_FMT_YUV420P;
    frame->width = imagewidth;
    frame->height = imageheight;


    // 在循环中设置每一帧的时间戳 如果没有这个可能就是0秒视频
    frame->pts = (((AV_TIME_BASE / 25))/10 * num);
   // qDebug() << "frame->pts===========" << frame->pts;


    if (av_frame_get_buffer(frame, 0) < 0) {
        qDebug() << "Failed to allocate frame buffer.";
        av_frame_free(&frame);
        return;
    }

    // 图像格式转换
    SwsContext* swsContext = sws_getContext(imagewidth, imageheight, AV_PIX_FMT_RGB32,
                                            frame->width, frame->height, AV_PIX_FMT_YUV420P,
                                            SWS_BICUBIC, nullptr, nullptr, nullptr);
    if (!swsContext) {
        qDebug() << "Failed to create SwsContext.";
        av_frame_free(&frame);
        return;
    }


    uint8_t* destData[4] = {frame->data[0], frame->data[1], frame->data[2], nullptr};
    int destLinesize[4] = {frame->linesize[0], frame->linesize[1], frame->linesize[2], 0};

    //av_image_fill_arrays(frame->data, frame->linesize, destData[0], codecContext->pix_fmt, codecContext->width, codecContext->height, 1);

    image = image.convertToFormat(QImage::Format_RGB32);
    const uchar* bits = image.constBits();
    int bytesPerLine = image.bytesPerLine();

    // 函数返回的值是转换后的图像的输出行数。输出的图像高度为图像像素。
    ret = sws_scale(swsContext, &bits, &bytesPerLine, 0, image.height(), destData, destLinesize);

    //qDebug() << "sws_scale ret==="<<ret;
    //函数用于释放由 sws_getContext 函数创建的图像格式转换上下文
    sws_freeContext(swsContext);

    //qDebug() << "AVPacket packet;";
    // 编码并写入视频帧
    AVPacket packet;
    av_init_packet(&packet);
    packet.data = nullptr;
    packet.size = 0;

    int code = -1;
    // 接收输出包
    while (code < 0) {
        ret = avcodec_send_frame(codecContext, frame);
       // qDebug() << "avcodec_send_frame ret===="<<ret;
        code = avcodec_receive_packet(codecContext, &packet);
        //qDebug() << "while avcodec_receive_packet====" << code;
        if(code == 0){
            // 处理输出包
            ret = av_interleaved_write_frame(formatContext, &packet);
          //  qDebug() << "av_interleaved_write_frame==================" << ret;
            av_packet_unref(&packet);  // 释放输出包
        } else if (code == AVERROR(EAGAIN)) {
            // 当输出队列为空时，需要重新发送帧进行编码
            continue;
        } else {
            qDebug() << "Error encoding frame: " << code;
            break;
        }
    }

    //qDebug() << "av_frame_free(&frame);";
    av_frame_free(&frame);
    //qDebug()<<"num==============================================="<<num;
    ++num;
}
void RecordingThread::stopMp4(){
	isRecord = 0;
}


void RecordingThread::setImage(QImage image){
	isRecord = 1;
	gQdata.push_back(image);
}

void RecordingThread::recordInit(){
	 while (1) {
        if(!gQdata.isEmpty() && gQdata.size()>0){
            QImage qimage = gQdata.dequeue();
			saveMp4(qimage);
        }else{
			if(isRecord == 0){
				isRecord = -1;
				num = 0;
				//写入尾部信息
				qDebug() << "av_write_trailer(formatContext)";	
				int ret = av_write_trailer(formatContext);
				qDebug() << "av_write_trailer(formatContext) ret==="<<ret;	
				emit send("stopRecode");
			}		
		}
        usleep(5000);
    }
}

我在使用FFmpeg的时候主要出现两个比较明显的情况:

1.pix_fmt为-1的情况,原因是

设置完成编码格式以后要立刻打开,要不然调用avcodec_parameters_to_context的时候会重置编码

2.合成的视频只有一帧的情况

//主要是因为这个参数导致的,你们可以根据自己的需求微调
// 在循环中设置每一帧的时间戳 如果没有这个可能就是0秒视频 
frame->pts = ((baseTimestamp + (num * (AV_TIME_BASE / 30)))/10);

嵌入式编译FFmpeg6.0版本并且组合x264_想取一个与众不同的名字好难的博客-CSDN博客

嵌入式编译x264源码_想取一个与众不同的名字好难的博客-CSDN博客