c++ - ffmpeg 和 boost::asio NULL 指针

Question

我正在尝试制作一个可以在多台核心机器上运行的特殊视频软件。

我想要许多 c++ 对象来流式传输视频文件和许多其他 c++ 对象来将流式数据存储到文件中。

我创建了一些简单的类，但是当我尝试创建 2 个或更多对象时，我得到了:

opening stream9079.sdp
[udp @ 0xaef5380] bind failed: Address already in use
Could not open input file stream9079.sdp
Segmentation fault (core dumped)

当我只使用一个对象时，一切都很好。

我使用以下代码

int main(int argc, char **argv)
{
    boost::asio::io_service ios;
    boost::asio::io_service ios1;

    Channel *channels[100];

    channels[0] = new Channel(ios, 9078, atoi(argv[1]));
    channels[0]->StartTimer(0);

    channels[1] = new Channel(ios1, 9079, atoi(argv[1]));
    channels[1]->StartTimer(0);

    boost::thread t(boost::bind(&worker, &ios));
    boost::thread t1(boost::bind(&worker, &ios1));


    t.join();
    t1.join();

    CEVLOG_MSG << "done" << std::endl;

    return 0;
}

我的 Channel类实现是:

#include "channel.hpp"
#include "utils.hpp"
#include "boost/lexical_cast.hpp"
Channel::Channel(boost::asio::io_service &ioP, int i, bool to_send):
    Runnable(ioP),
    work( new boost::asio::io_service::work(ioP) ),
    ofmt(NULL),
    ifmt_ctx(NULL),
    ofmt_ctx(NULL)
{
    id = i;
    sender = to_send;

    if (sender)
    {
            input.assign("/home/georgi/Downloads/video/IMG_0019.MOV");
            output.assign("rtp://10.101.3.60:"); output += boost::lexical_cast<std::string>(id);
    }
    else
    {
            input.assign("stream"); input += boost::lexical_cast<std::string>(id); input += ".sdp";
            output.assign("test"); output += boost::lexical_cast<std::string>(id); output += ".mp4";
    }

video_idx = audio_idx = sub_idx = -1;

    if (OpenInput())
    {
            if (sender)
                    OpenOutput(eStreamOutput);
            else
                    OpenOutput(eFileOutput);
    }
}

 Channel::~Channel()
 {
    av_write_trailer(ofmt_ctx);

    avformat_close_input(&ifmt_ctx);

    if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
            avio_closep(&ofmt_ctx->pb);

    avformat_free_context(ofmt_ctx);

    work.reset();
}

bool Channel::OpenInput()
{
    CEVLOG_MSG << "opening " << input << std::endl;

    int ret;
    if ((ret = avformat_open_input(&ifmt_ctx, input.c_str(), 0, 0)) < 0)
    {
            CEVLOG_ERR << "Could not open input file " << input << std::endl;
            return false;
    }

    CEVLOG_MSG << " " << ifmt_ctx << std::endl;

    if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0)
    {
            CEVLOG_ERR << "Failed to retrieve input stream information" << std::endl;
            return false;
    }

    ifmt_ctx->flags |= AVFMT_FLAG_GENPTS;

    //read and set timestamps to 0
av_read_frame(ifmt_ctx, &pkt);
pkt.pts = pkt.dts = 0;

return true;
}

bool Channel::OpenOutput(tOutputType WhatToOpen)
{
    int SDP_size;

    switch (WhatToOpen)
    {
    case eFileOutput:
            avformat_alloc_output_context2(&ofmt_ctx, NULL, NULL, output.c_str());
            break;

    case eStreamOutput:
            avformat_alloc_output_context2(&ofmt_ctx, NULL, "rtp", output.c_str());

            char SDP[4096];
            SDP_size = 4096;

            av_sdp_create(&ofmt_ctx, 1, SDP, SDP_size);
            CEVLOG_DBG << "SDP=" << SDP << std::endl;
            break;

    default:
            assert(false);
            break;
    }

    if (!ofmt_ctx)
    {
            CEVLOG_ERR << "Could not create output context" << std::endl;
            return false;
    }

    ofmt = ofmt_ctx->oformat;

    video_idx = FindIndex(AVMEDIA_TYPE_VIDEO);

    if (!(ofmt->flags & AVFMT_NOFILE))
    {
            if (avio_open(&ofmt_ctx->pb, output.c_str(), AVIO_FLAG_WRITE) < 0)
            {
                    CEVLOG_ERR << "Could not open output file " << output << std::endl;
                    return false;
            }
    }

    if (avformat_write_header(ofmt_ctx, NULL) < 0)
    {
            CEVLOG_ERR << "Error occurred when opening output file " << output << std::endl;
            return false;
    }

    return true;
}

unsigned int Channel::FindIndex(AVMediaType Type)
{
    int idx;

    for (idx = 0; idx < ifmt_ctx->nb_streams; idx++)
    {
            if (ifmt_ctx->streams[idx]->codec->codec_type == Type)
            {
                    AVStream *in_stream = ifmt_ctx->streams[idx];
                    AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);

                    if (!out_stream)
                    {
                            CEVLOG_ERR << "Failed allocating output stream" << std::endl;
                            break;
                    }

                    if (avcodec_copy_context(out_stream->codec, in_stream->codec) < 0)
                    {
                            CEVLOG_ERR << "Failed to copy context from input to output stream codec context" << std::endl;
                            break;
                    }

                    out_stream->codec->codec_tag = 0;
                    if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
                    {
                            out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
                    }

                    break;
            }
    }

    return idx;
 }

void Channel::Callback()
{
    if (sender)
            SendVideo();
    else
            RecvVideo();
}

void Channel::SendVideo()
{
    int ret = av_read_frame(ifmt_ctx, &pkt);
    int time_ms = 0;

    if (ret != 0)
    {
            av_write_trailer(ofmt_ctx);
            work.reset();
            return;
    }

    if (pkt.stream_index == video_idx)
    {
            AVStream *in_stream  = ifmt_ctx->streams[pkt.stream_index];
            AVStream *out_stream = ofmt_ctx->streams[pkt.stream_index];

            AVRational time_base = ifmt_ctx->streams[video_idx]->time_base;

            char timestamp[100];
            time_ms = 1000 * 1000 * strtof(timestamp2char(timestamp, pkt.duration, &time_base), NULL);

            pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
            pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
            pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
            pkt.pos = -1;

            ret = av_interleaved_write_frame(ofmt_ctx, &pkt);

            if (ret < 0)
            {
                    CEVLOG_ERR << "Error muxing packet" << std::endl;
                    return;
            }
    }

    av_free_packet(&pkt);

    StartTimer(time_ms);
}

void Channel::RecvVideo()
{
    int ret = av_read_frame(ifmt_ctx, &pkt);

    if (ret != 0)
    {
            //Some error or end of stream is detected. Write file trailer
            av_write_trailer(ofmt_ctx);
            work.reset();
            return;
    }

    //if is NOT video just continue reading
    if (pkt.stream_index == video_idx)
    {
            AVStream *in_stream  = ifmt_ctx->streams[pkt.stream_index];
            AVStream *out_stream = ofmt_ctx->streams[pkt.stream_index];

            AVRational time_base = ifmt_ctx->streams[video_idx]->time_base;

            pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
            pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, AV_ROUND_NEAR_INF);
            pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
            pkt.pos = -1;

            ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
            if (ret < 0)
            {
                    CEVLOG_ERR << "Error muxing packet" << std::endl;
                    return;
            }
    }

    av_free_packet(&pkt);

    StartTimer(0);
}

Answer 1

我不知道那些库，但看起来你正在多次抓取端口 9078 和 9079。