Qt开源作品2-视频流播放vlc内核

一、前言

上一个作品是ffmpeg内核做的，由于ffmpeg太过于强大，很多初学者会看的云里雾里懵逼状态，也有很多用户只需要一个简单的播放视频流即可，根本不需要涉及到负责的解码转码等，于是vlc就上场了，他就是直接对ffmpeg做了深层次的封装，提供了友好的接口，具备这种境界的还有个mpv之类的，mpv相比于vlc还更牛逼在库文件就一个，貌似是封装成了静态库，不想vlc还要带一堆的动态库文件和插件文件，当然vlc的简单在于只需要几行代码就可以撸起来，让初学者看到效果很重要，很兴奋，可以更快速的进行下一步的编码中，体验编码的乐趣。

二、代码思路

第一步：引入vlc的头文件

# ifdef __cplusplus
extern "C" {
# endif

#ifdef vlc3
#include <libvlc.h>
#include <libvlc_renderer_discoverer.h>
#include <libvlc_media.h>
#include <libvlc_media_player.h>
#include <libvlc_media_list.h>
#include <libvlc_media_list_player.h>
#include <libvlc_media_library.h>
#include <libvlc_media_discoverer.h>
#include <libvlc_events.h>
#include <libvlc_dialog.h>
#include <libvlc_vlm.h>
#include <deprecated.h>
#else
#include <libvlc.h>
#include <libvlc_structures.h>
#include <libvlc_media.h>
#include <libvlc_media_player.h>
#include <libvlc_media_list.h>
#include <libvlc_media_list_player.h>
#include <libvlc_media_library.h>
#include <libvlc_media_discoverer.h>
#include <libvlc_events.h>
#include <libvlc_vlm.h>
#include <deprecated.h>
#endif

# ifdef __cplusplus
}
# endif

第二步：设置句柄打开视频流

bool VlcThread::init()
{
    const char *tempArg = "";
    const char *vlc_args[9] = {"-I", "dummy", "--no-osd", "--no-stats", "--ignore-config", "--no-video-on-top", "--no-video-title-show", "--no-snapshot-preview", tempArg};
    vlcInst = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);
    if (vlcInst == NULL) {
        return false;
    }

    vlcMedia = libvlc_media_new_location(vlcInst, url.toUtf8().constData());
    vlcPlayer = libvlc_media_player_new_from_media(vlcMedia);
    if (vlcPlayer == NULL) {
        return false;
    }

    //设置播放句柄
    VlcWidget *w = (VlcWidget *)this->parent();
#if defined(Q_OS_WIN)
    libvlc_media_player_set_hwnd(vlcPlayer, (void *)w->winId());
#elif defined(Q_OS_LINUX)
    libvlc_media_player_set_xwindow(vlcPlayer, w->winId());
#elif defined(Q_OS_MAC)
    libvlc_media_player_set_nsobject(vlcPlayer, (void *)w->winId());
#endif

    //设置硬件加速 none auto any d3d11va dxva2
    setOption(QString(":avcodec-hw=%1").arg("none"));
    //设置通信协议 tcp udp
    setOption(QString(":rtsp-%1").arg("tcp"));
    //设置缓存时间 默认500毫秒
    setOption(QString(":network-caching=%1").arg(300));

    libvlc_media_player_play(vlcPlayer);
    //qDebug() << TIMEMS << "init vlc finsh";
    return true;
}

第三步：暂停及释放资源

void VlcThread::pause()
{
    if (vlcPlayer != NULL) {
        libvlc_media_player_pause(vlcPlayer);
    }
}

void VlcThread::next()
{
    if (vlcPlayer != NULL) {
        libvlc_media_player_pause(vlcPlayer);
    }
}

void VlcThread::free()
{
    if (vlcInst != NULL) {
        libvlc_release(vlcInst);
        vlcInst = NULL;
    }

    if (vlcMedia != NULL) {
        libvlc_media_release(vlcMedia);
        vlcMedia = NULL;
    }

    if (vlcPlayer != NULL) {
        libvlc_media_player_release(vlcPlayer);
        vlcPlayer = NULL;
    }

    //qDebug() << TIMEMS << "close vlc ok";
}