FFMPEG音频视频开发：QT采集摄像头数据帧与声卡音频通过FFMPEG实时推流到RTMP服务器(v1.0)-阿里云开发者社区

如果已经完成FFMPEG录制视频保存到本地的功能，完成RTMP推流只需要修改几行代码即可完成。

推流到RTMP服务器与保存到本地的代码基本相同，主要是输出地址不一样。保存到本地就是本地文件名称，推流到RTMP服务器，就将文件名称换成RTMP服务器地址即可。

完整项目代码下载地址(下载即可编译运行，不懂可以私信): https://download.csdn.net/download/xiaolong1126626497/19323232

主要修改的代码:

filename="rtmp://js.live-send.acg.tv/live-js/?xxxxxxxx"
avformat_alloc_output_context2(&oc,nullptr,"flv",filename); //文件名称替换成网络地址
//指定编码器
fmt->video_codec=AV_CODEC_ID_H264;
fmt->audio_codec=AV_CODEC_ID_AAC;

FFMPEG保存视频到本地的文章:

https://blog.csdn.net/xiaolong1126626497/article/details/104858499

video_audio_encode.cpp的完整代码:

#include "video_audio_encode.h"
class VideoAudioEncode videoaudioencode;
Thread_VideoAudioEncode thread_VideoenCode; //视频音频编码的线程
char audio_buffer[AUDIO_BUFFER_MAX_SIZE];     //音频缓存
int audio_buffer_r_count=0;
int audio_buffer_w_count=0;
//音频相关参数设置
#define AUDIO_RATE_SET 44100      //音频采样率
#define AUDIO_BIT_RATE_SET  64000 //设置码率
#define AUDIO_CHANNEL_SET   AV_CH_LAYOUT_MONO  //AV_CH_LAYOUT_MONO 单声道   AV_CH_LAYOUT_STEREO 立体声
#define STREAM_DURATION   60*10.0   //录制时间秒单位
#define STREAM_FRAME_RATE 30     /* 30 images/s   图片是多少帧1秒*/
#define STREAM_PIX_FMT    AV_PIX_FMT_YUV420P /* default pix_fmt 视频图像格式 */
#define SCALE_FLAGS SWS_BICUBIC
// 单个输出AVStream的包装器
typedef struct OutputStream {
    AVStream *st;
    AVCodecContext *enc;
    /* 下一帧的点数*/
    int64_t next_pts;
    int samples_count;
    AVFrame *frame;
    AVFrame *tmp_frame;
    float t, tincr, tincr2;
    struct SwsContext *sws_ctx;
    struct SwrContext *swr_ctx;
} OutputStream;
static int write_frame(AVFormatContext *fmt_ctx, const AVRational *time_base, AVStream *st, AVPacket *pkt)
{
    /*将输出数据包时间戳值从编解码器重新调整为流时基 */
    av_packet_rescale_ts(pkt, *time_base, st->time_base);
    pkt->stream_index = st->index;
    /*将压缩的帧写入媒体文件*/
    return av_interleaved_write_frame(fmt_ctx, pkt);
}
/* 添加输出流。 */
static void add_stream(OutputStream *ost, AVFormatContext *oc,
                       AVCodec **codec,
                       enum AVCodecID codec_id)
{
    AVCodecContext *c;
    int i;
    /* find the encoder */
    *codec = avcodec_find_encoder(codec_id);
    if (!(*codec)) {
        qDebug("Could not find encoder for '%s'\n",avcodec_get_name(codec_id));
        exit(1);
    }
    ost->st = avformat_new_stream(oc, nullptr);
    if (!ost->st) {
        qDebug("Could not allocate stream\n");
        exit(1);
    }
    ost->st->id = oc->nb_streams-1;
    c = avcodec_alloc_context3(*codec);
    if (!c) {
        qDebug("Could not alloc an encoding context\n");
        exit(1);
    }
    ost->enc = c;
    switch ((*codec)->type) {
    case AVMEDIA_TYPE_AUDIO:
        //设置数据格式
        //c->sample_fmt  = (*codec)->sample_fmts ? (*codec)->sample_fmts[0] : AV_SAMPLE_FMT_FLTP;
        c->sample_fmt  = AV_SAMPLE_FMT_FLTP;
        c->bit_rate    = AUDIO_BIT_RATE_SET;  //设置码率
        c->sample_rate = AUDIO_RATE_SET;  //音频采样率
        //编码器支持的采样率
        if ((*codec)->supported_samplerates)
        {
            c->sample_rate = (*codec)->supported_samplerates[0];
            for (i = 0; (*codec)->supported_samplerates[i]; i++)
            {
                //判断编码器是否支持
                if ((*codec)->supported_samplerates[i] == AUDIO_RATE_SET)
                {
                     c->sample_rate = AUDIO_RATE_SET;
                }
            }
        }
        //设置采样通道
        c->channels= av_get_channel_layout_nb_channels(c->channel_layout);
        c->channel_layout = AUDIO_CHANNEL_SET; //AV_CH_LAYOUT_MONO 单声道   AV_CH_LAYOUT_STEREO 立体声
        if ((*codec)->channel_layouts)
        {
            c->channel_layout = (*codec)->channel_layouts[0];
            for (i = 0; (*codec)->channel_layouts[i]; i++)
            {
                if ((*codec)->channel_layouts[i] == AUDIO_CHANNEL_SET)
                {
                    c->channel_layout = AUDIO_CHANNEL_SET;
                }
            }
        }
        c->channels        = av_get_channel_layout_nb_channels(c->channel_layout);
        ost->st->time_base = (AVRational){ 1, c->sample_rate };
        break;
    case AVMEDIA_TYPE_VIDEO:
        c->codec_id = codec_id;
        //码率：影响体积，与体积成正比：码率越大，体积越大；码率越小，体积越小。
        c->bit_rate = 400000; //设置码率 400kps
        /*分辨率必须是2的倍数。 */
        c->width    = 640;
        c->height   = 480;
        /*时基：这是基本的时间单位（以秒为单位）
         *表示其中的帧时间戳。 对于固定fps内容，
         *时基应为1 / framerate，时间戳增量应为
         *等于1。*/
        ost->st->time_base = (AVRational){1,STREAM_FRAME_RATE};
        c->time_base       = ost->st->time_base;
        c->gop_size      = 12; /* 最多每十二帧发射一帧内帧 */
        c->pix_fmt       = STREAM_PIX_FMT;
        if(c->codec_id == AV_CODEC_ID_MPEG2VIDEO)
        {
            /* 只是为了测试，添加了B帧 */
            c->max_b_frames = 2;
        }
        if (c->codec_id == AV_CODEC_ID_MPEG1VIDEO) {
            /*需要避免使用其中一些系数溢出的宏块。
             *普通视频不会发生这种情况，因为
             *色度平面的运动与亮度平面不匹配。 */
            c->mb_decision = 2;
        }
    break;
    default:
        break;
    }
    /* 某些格式希望流头分开。 */
    if (oc->oformat->flags & AVFMT_GLOBALHEADER)
        c->flags |= AV_CODEC_FLAG_GLOBAL_HEADER;
}
/**************************************************************/
/* audio output */
static AVFrame *alloc_audio_frame(enum AVSampleFormat sample_fmt,
                                  uint64_t channel_layout,
                                  int sample_rate, int nb_samples)
{
    AVFrame *frame = av_frame_alloc();
    int ret;
    if (!frame) {
        qDebug("Error allocating an audio frame\n");
        exit(1);
    }
    frame->format = sample_fmt;
    frame->channel_layout = channel_layout;
    frame->sample_rate = sample_rate;
    frame->nb_samples = nb_samples;
    if (nb_samples) {
        ret = av_frame_get_buffer(frame, 0);
        if (ret < 0) {
            qDebug("Error allocating an audio buffer\n");
            exit(1);
        }
    }
    return frame;
}
static void open_audio(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
    AVCodecContext *c;
    int nb_samples;
    int ret;
    AVDictionary *opt = nullptr;
    c = ost->enc;
    /* open it */
    av_dict_copy(&opt, opt_arg, 0);
    ret = avcodec_open2(c, codec, &opt);
    av_dict_free(&opt);
    if (ret < 0) {
        qDebug("无法打开音频编解码器\n");
        exit(1);
    }
    /* 初始化信号发生器 */
    ost->t     = 0;
    ost->tincr = 2 * M_PI * 110.0 / c->sample_rate;
    /* 每秒增加110 Hz的频率 */
    ost->tincr2 = 2 * M_PI * 110.0 / c->sample_rate / c->sample_rate;
    if (c->codec->capabilities & AV_CODEC_CAP_VARIABLE_FRAME_SIZE)
        nb_samples = 10000;
    else
        nb_samples = c->frame_size;
    ost->frame     = alloc_audio_frame(c->sample_fmt, c->channel_layout,
                                       c->sample_rate, nb_samples);
    ost->tmp_frame = alloc_audio_frame(AV_SAMPLE_FMT_S16, c->channel_layout,
                                       c->sample_rate, nb_samples);
    /*将流参数复制到多路复用器 */
    ret = avcodec_parameters_from_context(ost->st->codecpar, c);
    if (ret < 0) {
        qDebug("无法复制流参数\n");
        exit(1);
    }
    /* 创建重采样器上下文 */
        ost->swr_ctx = swr_alloc();
        if(!ost->swr_ctx)
        {
            qDebug("无法分配重采样器上下文\n");
            exit(1);
        }
       /* 设定选项 */
        av_opt_set_int       (ost->swr_ctx, "in_channel_count",   c->channels,       0);
        av_opt_set_int       (ost->swr_ctx, "in_sample_rate",     c->sample_rate,    0);
        av_opt_set_sample_fmt(ost->swr_ctx, "in_sample_fmt",      AV_SAMPLE_FMT_S16, 0);//带符号16bit
        av_opt_set_int       (ost->swr_ctx, "out_channel_count",  c->channels,       0);
        av_opt_set_int       (ost->swr_ctx, "out_sample_rate",    c->sample_rate,    0);
        av_opt_set_sample_fmt(ost->swr_ctx, "out_sample_fmt",     c->sample_fmt,     0);
        qDebug("音频通道数=%d\n",c->channels);
        qDebug("音频采样率=%d\n",c->sample_rate);
        /* 初始化重采样上下文 */
        if ((ret = swr_init(ost->swr_ctx)) < 0) {
            qDebug("无法初始化重采样上下文\n");
            exit(1);
        }
}
/*准备一个'frame_size'样本的16位虚拟音频帧，然后'nb_channels'频道。 */
static AVFrame *get_audio_frame(OutputStream *ost)
{
    AVFrame *frame = ost->tmp_frame;
    int j, i, v;
    int16_t *q = (int16_t*)frame->data[0];
    /* 检查我们是否要生成更多帧----用于判断是否结束*/
    if(av_compare_ts(ost->next_pts, ost->enc->time_base,
                      STREAM_DURATION, (AVRational){ 1, 1 }) >= 0)
        return nullptr;
    // qDebug("frame->nb_samples=%d\n",frame->nb_samples); //1024
    // qDebug("ost->enc->channels=%d\n",ost->enc->channels);
    //消费者
    // videoaudioencode.audio_encode_mutex.lock();
    // videoaudioencode.audio_encode_Condition.wait(&videoaudioencode.audio_encode_mutex);
    // memcpy(audio_buffer_temp,audio_buffer,sizeof(audio_buffer));
    // videoaudioencode.audio_encode_mutex.unlock();
#if 1
    if(audio_buffer_r_count>=AUDIO_BUFFER_MAX_SIZE)audio_buffer_r_count=0;
    //音频数据赋值
    for(j = 0; j<frame->nb_samples; j++)  //nb_samples: 此帧描述的音频样本数（每个通道）
    {
        for(i=0;i<ost->enc->channels;i++)  //channels:音频通道数
        {
            *q++ = audio_buffer[j+audio_buffer_r_count];  //音频数据
        }
        ost->t     += ost->tincr;
        ost->tincr += ost->tincr2;
    }
    frame->pts = ost->next_pts;
    ost->next_pts  += frame->nb_samples;
    //qDebug()<<"audio_buffer_r_count="<<audio_buffer_r_count;
    audio_buffer_r_count+=1024;
#else
    for(j = 0; j<frame->nb_samples; j++)  //nb_samples: 此帧描述的音频样本数（每个通道）
       {
           v=(int)(sin(ost->t) * 1000);
           for(i=0;i<ost->enc->channels;i++)  //channels:音频通道数
           {
               *q++ = v;  //音频数据
           }
           ost->t     += ost->tincr;
           ost->tincr += ost->tincr2;
       }
    frame->pts = ost->next_pts;
    ost->next_pts  += frame->nb_samples;
#endif
    return frame;
}
/*
 *编码一个音频帧并将其发送到多路复用器
 *编码完成后返回1，否则返回0
 */
static int write_audio_frame(AVFormatContext *oc, OutputStream *ost)
{
    AVCodecContext *c;
    AVPacket pkt = { 0 }; // data and size must be 0;
    AVFrame *frame;
    int ret;
    int got_packet;
    int dst_nb_samples;
    av_init_packet(&pkt);
    c = ost->enc;
    frame = get_audio_frame(ost);
    if(frame)
    {
        /*使用重采样器将样本从本机格式转换为目标编解码器格式*/
         /*计算样本的目标数量*/
            dst_nb_samples = av_rescale_rnd(swr_get_delay(ost->swr_ctx, c->sample_rate) + frame->nb_samples,
                                            c->sample_rate, c->sample_rate, AV_ROUND_UP);
            av_assert0(dst_nb_samples == frame->nb_samples);
        /*当我们将帧传递给编码器时，它可能会保留对它的引用
         *内部；
         *确保我们不会在这里覆盖它
         */
        ret = av_frame_make_writable(ost->frame);
        if (ret < 0)
            exit(1);
        /*转换为目标格式 */
        ret = swr_convert(ost->swr_ctx,
                          ost->frame->data, dst_nb_samples,
                          (const uint8_t **)frame->data, frame->nb_samples);
        if (ret < 0) {
            qDebug("Error while converting\n");
            exit(1);
        }
        frame = ost->frame;
        frame->pts = av_rescale_q(ost->samples_count, (AVRational){1, c->sample_rate}, c->time_base);
        ost->samples_count += dst_nb_samples;
    }
    ret = avcodec_encode_audio2(c, &pkt, frame, &got_packet);
    if (ret < 0) {
        qDebug("Error encoding audio frame\n");
        exit(1);
    }
    if (got_packet) {
        ret = write_frame(oc, &c->time_base, ost->st, &pkt);
        if (ret < 0) {
            qDebug("Error while writing audio frame\n");
            exit(1);
        }
    }
    return (frame || got_packet) ? 0 : 1;
}
/**************************************************************/
/* video output */
static AVFrame *alloc_picture(enum AVPixelFormat pix_fmt, int width, int height)
{
    AVFrame *picture;
    int ret;
    picture = av_frame_alloc();
    if (!picture)
        return nullptr;
    picture->format = pix_fmt;
    picture->width  = width;
    picture->height = height;
    /* allocate the buffers for the frame data */
    ret = av_frame_get_buffer(picture, 32);
    if(ret < 0)
    {
        qDebug("Could not allocate frame data.\n");
        exit(1);
    }
    return picture;
}
static void open_video(AVFormatContext *oc, AVCodec *codec, OutputStream *ost, AVDictionary *opt_arg)
{
    int ret;
    AVCodecContext *c = ost->enc;
    AVDictionary *opt = nullptr;
    av_dict_copy(&opt, opt_arg, 0);
    /* open the codec */
    ret = avcodec_open2(c, codec, &opt);
    av_dict_free(&opt);
    if (ret < 0) {
        qDebug("Could not open video codec\n");
        exit(1);
    }
    /* allocate and init a re-usable frame */
    ost->frame = alloc_picture(c->pix_fmt, c->width, c->height);
    if (!ost->frame) {
        qDebug("Could not allocate video frame\n");
        exit(1);
    }
    ost->tmp_frame = nullptr;
    /* 将流参数复制到多路复用器 */
    ret = avcodec_parameters_from_context(ost->st->codecpar, c);
    if (ret < 0) {
        qDebug("Could not copy the stream parameters\n");
        exit(1);
    }
}
/*
准备图像数据
YUV422占用内存空间 = w * h * 2
YUV420占用内存空间 = width*height*3/2
*/
static int fill_yuv_image(AVFrame *pict, int frame_index,int width, int height)
{
    unsigned int y_size=width*height;
    //消费者
    while(videoaudioencode.void_data_queue.isEmpty())
    {
        QThread::msleep(10);
        if(videoaudioencode.run_flag==0) //停止编码
        {
            return -1;
        }
    }
    videoaudioencode.video_encode_mutex.lock();
    QByteArray byte=videoaudioencode.void_data_queue.dequeue();
    //qDebug()<<"out="<<videoaudioencode.void_data_queue.size();
    videoaudioencode.video_encode_mutex.unlock();
    //将YUV数据拷贝到缓冲区  y_size=wXh
    memcpy(pict->data[0],byte.data(),y_size);
    memcpy(pict->data[1],byte.data()+y_size,y_size/4);
    memcpy(pict->data[2],byte.data()+y_size+y_size/4,y_size/4);
    return 0;
}
static AVFrame *get_video_frame(OutputStream *ost)
{
    AVCodecContext *c = ost->enc;
    /* 检查我们是否要生成更多帧---判断是否结束录制 */
      if(av_compare_ts(ost->next_pts, c->time_base,STREAM_DURATION, (AVRational){ 1, 1 }) >= 0)
        return nullptr;
    /*当我们将帧传递给编码器时，它可能会保留对它的引用
    *内部； 确保我们在这里不覆盖它*/
    if (av_frame_make_writable(ost->frame) < 0)
        exit(1);
    //制作虚拟图像
    //DTS（解码时间戳）和PTS（显示时间戳）
    int err=fill_yuv_image(ost->frame, ost->next_pts, c->width, c->height);
    if(err)return nullptr;
    ost->frame->pts = ost->next_pts++;
    return ost->frame;
}
/*
*编码一个视频帧并将其发送到多路复用器
*编码完成后返回1，否则返回0
*/
static int write_video_frame(AVFormatContext *oc, OutputStream *ost)
{
    int ret;
    AVCodecContext *c;
    AVFrame *frame;
    int got_packet = 0;
    AVPacket pkt = {0};
    c=ost->enc;
    //获取一帧数据
    frame = get_video_frame(ost);
    if(frame==nullptr)return 1;
    av_init_packet(&pkt);
    /* 编码图像 */
    ret=avcodec_encode_video2(c, &pkt, frame, &got_packet);
    if(ret < 0)
    {
        qDebug("Error encoding video frame\n");
        exit(1);
    }
    if(got_packet)
    {
        ret=write_frame(oc, &c->time_base, ost->st, &pkt);
    }
    else
    {
        ret = 0;
    }
    if(ret < 0)
    {
        qDebug("Error while writing video frame\n");
        exit(1);
    }
    return (frame || got_packet) ? 0 : 1;
}
static void close_stream(AVFormatContext *oc, OutputStream *ost)
{
    avcodec_free_context(&ost->enc);
    av_frame_free(&ost->frame);
    av_frame_free(&ost->tmp_frame);
    sws_freeContext(ost->sws_ctx);
    swr_free(&ost->swr_ctx);
}
int Thread_VideoAudioEncode::StartUp_VideoAudioEncode()
{
    OutputStream video_st = {0}, audio_st = { 0 };
    AVOutputFormat *fmt;
    AVFormatContext *oc;
    AVCodec *audio_codec, *video_codec;
    int ret;
    int have_video = 0, have_audio = 0;
    int encode_video = 0, encode_audio = 0;
    AVDictionary *opt = nullptr;
    QDateTime dateTime(QDateTime::currentDateTime());
    //时间效果: 2020-03-05 16:25::04 周四
    QString qStr="";
    qStr+=SAVE_FILE_PATH;  //Android 手机的照相机文件夹
    qStr+=dateTime.toString("yyyy-MM-dd-hh-mm-ss");
    qStr+=".mp4";
    qStr="rtmp://js.live-send.acg.tv/live-js/?streamname=live_68130189_71037877&key=b95d4cfda0c196518f104839fe5e7573";
    char filename[500];
    strcpy(filename,qStr.toLatin1().data());
    emit LogSend(tr("当前的文件名称:%1\n").arg(filename));
   /* 分配输出环境 */
    //avformat_alloc_output_context2(&oc,nullptr,nullptr,filename); //存放到文件
    avformat_alloc_output_context2(&oc,nullptr,"flv",filename); //发布到网络
    if(!oc)
    {
        emit LogSend("code error.\n");
        return -1;
    }
    fmt=oc->oformat;
    fmt->video_codec=AV_CODEC_ID_H264;
    fmt->audio_codec=AV_CODEC_ID_AAC;
     /*使用默认格式的编解码器添加音频和视频流，初始化编解码器。 */
    if(fmt->video_codec != AV_CODEC_ID_NONE)
    {
        add_stream(&video_st,oc,&video_codec,fmt->video_codec);
        have_video = 1;
        encode_video = 1;
    }
    if(fmt->audio_codec != AV_CODEC_ID_NONE)
    {
        add_stream(&audio_st, oc, &audio_codec, fmt->audio_codec);
        have_audio = 1;
        encode_audio = 1;
    }
  /*现在已经设置了所有参数，可以打开音频视频编解码器，并分配必要的编码缓冲区。 */
    if (have_video)
        open_video(oc, video_codec, &video_st, opt);
    if (have_audio)
        open_audio(oc, audio_codec, &audio_st, opt);
    av_dump_format(oc, 0, filename, 1);
    /* 打开输出文件（如果需要） */
    if(!(fmt->flags & AVFMT_NOFILE))
    {
        qDebug()<<"存放视频到文件.\n";
        ret = avio_open(&oc->pb, filename, AVIO_FLAG_WRITE);
        if (ret < 0)
        {
            qDebug("Could not open '%s'\n",filename);
            return -1;
        }
    }
    /* 编写流头（如果有）*/
    ret=avformat_write_header(oc,&opt);
    if(ret<0)
    {
        qDebug("Error occurred when opening output file\n");
        return -1;
    }
    while(encode_video || encode_audio)
    {
        /* 选择要编码的流*/
        if(encode_video &&(!encode_audio || av_compare_ts(video_st.next_pts, video_st.enc->time_base,audio_st.next_pts, audio_st.enc->time_base) <= 0))
        {
            QElapsedTimer mstimer;
            mstimer.start();
            encode_video = !write_video_frame(oc,&video_st);
            double time = (double)mstimer.nsecsElapsed()/(double)1000000;
            qDebug() <<"video_encode:"<< time<<"ms";
        }
        else
        {
            QElapsedTimer mstimer;
            mstimer.start();
            encode_audio = !write_audio_frame(oc,&audio_st);
            double time = (double)mstimer.nsecsElapsed()/(double)1000000;
            qDebug() <<"audio_encode:"<< time<<"ms";
        }
    }
    /*编写预告片（如果有）。 预告片必须在之前写好
    *关闭在编写标头时打开的CodecContext； 除此以外
    * av_write_trailer（）可能会尝试使用已释放的内存
    * av_codec_close（）。 */
    av_write_trailer(oc);
    /* Close each codec. */
    if (have_video)
        close_stream(oc, &video_st);
    if (have_audio)
        close_stream(oc, &audio_st);
    if (!(fmt->flags & AVFMT_NOFILE))
        /* Close the output file. */
        avio_closep(&oc->pb);
    /* free the stream */
    avformat_free_context(oc);
    qDebug("编码完成.线程退出.\n");
    return 0;
}
//编码
void Thread_VideoAudioEncode ::run()
{
    while(1)
    {
        qDebug()<<"编码线程开始运行.";
        audio_buffer_r_count=0;
        audio_buffer_w_count=0;
        StartUp_VideoAudioEncode(); //启动视频音频编码
        if(videoaudioencode.run_flag==0) //判断是否停止编码
        {
            break;
        }
    }
}

FFMPEG音频视频开发：QT采集摄像头数据帧与声卡音频通过FFMPEG实时推流到RTMP服务器(v1.0)

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