音视频项目—基于FFmpeg和SDL的音视频播放器解析（二十二）

介绍

在本系列，我打算花大篇幅讲解我的 gitee 项目音视频播放器，在这个项目，您可以学到音视频解封装，解码，SDL渲染相关的知识。您对源代码感兴趣的话，请查看基于FFmpeg和SDL的音视频播放器

如果您不理解本文，可参考我的前一篇文章音视频项目---基于FFmpeg和SDL的音视频播放器解析（二十一）

解析

我们播放器所有的类已经解析完了，我们来看一下 main 函数如何使用函数，实现音视频的播放。

cpp 复制代码

#include <iostream>
#include "log.h"
#include "demuxthread.h"
#include "avframequeue.h"
#include "decodethread.h"
#include "audiooutput.h"
#include "videooutput.h"
using namespace std;

#undef main
int main(int argc, char *argv[])
{
    int ret = 0;
    cout << "Hello World!" << endl;
    LogInit();
    // queue
    AVPacketQueue audio_packet_queue;
    AVPacketQueue video_packet_queue;

    AVFrameQueue audio_frame_queue;
    AVFrameQueue video_frame_queue;

    AVSync avsync;
    avsync.InitClock();

    //1 .解复用
    DemuxThread *demux_thread = new DemuxThread(&audio_packet_queue, &video_packet_queue);
    ret = demux_thread->Init(argv[1]);
    if(ret < 0) {
        LogError("demux_thread.Init failed");
        return -1;
    }

    ret = demux_thread->Start();
    if(ret < 0) {
        LogError("demux_thread.Start() failed");
        return -1;
    }

    // 解码线程初始化
    DecodeThread *audio_decode_thread = new DecodeThread(&audio_packet_queue, &audio_frame_queue);

    ret = audio_decode_thread->Init(demux_thread->AudioCodecParameters());
    if(ret < 0) {
        LogError("audio_decode_thread->Init() failed");
        return -1;
    }
    ret = audio_decode_thread->Start();
    if(ret < 0) {
        LogError("audio_decode_thread->Start() failed");
        return -1;
    }

    DecodeThread *video_decode_thread = new DecodeThread(&video_packet_queue, &video_frame_queue);

    ret = video_decode_thread->Init(demux_thread->VideoCodecParameters());
    if(ret < 0) {
        LogError("video_decode_thread->Init() failed");
        return -1;
    }
    ret = video_decode_thread->Start();
    if(ret < 0) {
        LogError("video_decode_thread->Start() failed");
        return -1;
    }


    // 初始化audio输出
    AudioParams audio_params = {0};
    memset(&audio_params, 0, sizeof(AudioParams));
    audio_params.channels = demux_thread->AudioCodecParameters()->channels;
    audio_params.channel_layout = demux_thread->AudioCodecParameters()->channel_layout;
    audio_params.fmt = (enum AVSampleFormat) demux_thread->AudioCodecParameters()->format;
    audio_params.freq = demux_thread->AudioCodecParameters()->sample_rate;
    audio_params.frame_size =demux_thread->AudioCodecParameters()->frame_size;

    AudioOutput *audio_output = new AudioOutput(&avsync, demux_thread->AudioStreamTimebase(), audio_params, &audio_frame_queue);
    ret = audio_output->Init();
    if(ret < 0) {
        LogError("audio_output->Init() failed");
        return -1;
    }

    VideoOutput *video_output = new VideoOutput(&avsync, demux_thread->VideoStreamTimebase(),
                                                &video_frame_queue, demux_thread->VideoCodecParameters()->width,
                                                demux_thread->VideoCodecParameters()->height);

    ret = video_output->Init();
    if(ret < 0) {
        LogError("video_output->Init() failed");
        return -1;
    }
    video_output->MainLoop();


    // 休眠120秒
//    std::this_thread::sleep_for(std::chrono::milliseconds(120*1000));

    LogInfo("demux_thread->Stop");
    demux_thread->Stop();
    LogInfo("delete demux_thread");
    delete demux_thread;

    LogInfo("audio_decode_thread->Stop()");
    audio_decode_thread->Stop();
    LogInfo("delete audio_decode_thread");
    delete audio_decode_thread;

    LogInfo("video_decode_thread->Stop()");
    video_decode_thread->Stop();
    LogInfo("delete video_decode_thread");
    delete video_decode_thread;

    LogInfo("main finish");

    return 0;
}

基本流程就是解复用------》解码------》输出音频 / 输出视频

好了，未来如果有需要的再深入解析这个 main，现在这个项目先告一段落。