一、了解vlc常用API
libvlc_new
LIBVLC_API libvlc_instance_t *
libvlc_new( int argc , const char *const *argv );
返回值是
libvlc_instance_t*vlc播放器实例
看起来很简单的函数，里面学问很大，我个人喜欢这样使用它
/* Load the VLC engine */
const char* const vlc_args[] = {
"--demux=h264",
"--ipv4",
"--no-prefer-system-codecs",
"--rtsp-caching=300",
"--network-caching=500", //网络额外缓存值 (ms)
"--rtsp-frame-buffer-size=10000000",
"--rtsp-tcp", //RTSP采用TCP传输方式
};
libvlc_inst = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);
当然也可以通过libvlc_media_add_option设置这些参数
libvlc_media_add_option(vlc_media, ":demux=h264");
如果是本地文件，非网络串流，你只要了解 demux 解码方式即可，解码方式有哪些呢？
--demux={
any,mp4,avi,asf,es,flacsys,tta,nuv,mpc,wav,caf,sid,sap,mkv,ogg,diracsys,live555,smf,adaptive,webvtt,ttml,voc,gme,rawvid,pva,image,ts,aiff,mod,directory,xa,au,nsv,ps,ty,h26x,h26x,mjpeg,mpgv,dvdnav,libbluray,rawdv,demux_cdg,nsc,avcodec,ps,vobsub,demux_stl,vc1,demuxdump,webvtt,real,subtitle,stats,es,rawaud,none}
vlc很强大，支持解码当下几乎所有数据流，当然自定义的私有流不在此列
libvlc_media_new_location/libvlc_media_new_path
LIBVLC_API libvlc_media_t *libvlc_media_new_location(
libvlc_instance_t *p_instance,
const char * psz_mrl );
LIBVLC_API libvlc_media_t *libvlc_media_new_path(
libvlc_instance_t *p_instance,
const char *path );
返回值是
libvlc_media_t *vlc音视频文件指针
libvlc_media_new_location 和 libvlc_media_new_path 这两个函数是一对
libvlc_media_new_location 用于加载网络串流，例如rtsp流，加载的通常是形如 rtsp://wowzaec2demo.streamlock.net/vod/mp4:BigBuckBunny_115k.mov的网络串流
libvlc_media_new_path 用于加载本地文件播放
libvlc_media_player_new_from_media
LIBVLC_API libvlc_media_player_t * libvlc_media_player_new_from_media( libvlc_media_t *p_md );
创建vlc播放环境，返回一个
libvlc_media_player_t*指针
libvlc_media_release
libvlc_media_release 和 libvlc_media_player_new_from_media是一对，当视频文件被加载到vlc播放环境之后要释放掉
//从音视频文件中创建vlc播放器
libvlc_media_player_t*libvlc_mp = libvlc_media_player_new_from_media(libvlc_m);
//释放音视频文件资源
libvlc_media_release(libvlc_m);
libvlc_media_player_play
LIBVLC_API int libvlc_media_player_play ( libvlc_media_player_t *p_mi );
当这个函数执行的时候视频才开始播放
libvlc_media_player_set_hwnd
这个函数是设置播放器的播放窗口，在UI设置里面要用到
MFC直接就可以获取 hwnd 窗口句柄，qt中需要先获取WId,然后才可以设置播放窗口
//qt下设置播放窗口
WId libvlc_WId = libvlc_mainWindow->winId();
libvlc_media_player_set_hwnd(libvlc_mp, (void*)libvlc_WId);
libvlc_media_player_stop
LIBVLC_API void libvlc_media_player_stop ( libvlc_media_player_t *p_mi );
结束播放
libvlc_media_player_release
LIBVLC_API void libvlc_media_player_release( libvlc_media_player_t *p_mi );
释放播放器资源
libvlc_release
LIBVLC_API void libvlc_release( libvlc_instance_t *p_instance );
释放播放器实例资源
这三个函数几乎是放在一起用的，具体看后面的VlcPlayer播放器对象封装
二、了解vlc播放状态
typedef enum libvlc_state_t
{
libvlc_NothingSpecial=0, //播放准备状态
libvlc_Opening, //libvlc_media_player_new_from_media调用后触发该状态
libvlc_Buffering, /* XXX: Deprecated value. Check the
* libvlc_MediaPlayerBuffering event to know the
* buffering state of a libvlc_media_player */
libvlc_Playing,
libvlc_Paused,
libvlc_Stopped,
libvlc_Ended,
libvlc_Error
} libvlc_state_t;
这个状态看着没啥用，但是对于理解播放器的播放过程至关重要
三、了解vlc事件处理
libvlc_event_e ：事件类型
libvlc_event_manager_t：事件管理器
他们怎么联系起来呢？通过 libvlc_media_player_event_manager 订阅事件
LIBVLC_API libvlc_event_manager_t * libvlc_media_player_event_manager ( libvlc_media_player_t *p_mi );
订阅完事件需要给事件注册事件处理函数
libvlc_event_attach
LIBVLC_API int libvlc_event_attach( libvlc_event_manager_t *p_event_manager,
libvlc_event_type_t i_event_type,
libvlc_callback_t f_callback,
void *user_data );
为了不一个个注册，直接循环注册，qt使用如下
// 事件列表
QList<libvlc_event_e> events;
events << libvlc_MediaPlayerOpening
<< libvlc_MediaPlayerBuffering
<< libvlc_MediaPlayerPlaying
<< libvlc_MediaPlayerPaused
<< libvlc_MediaPlayerStopped
<< libvlc_MediaPlayerEncounteredError
<< libvlc_MediaPlayerEndReached;
// 订阅事件
libvlc_eventManager = libvlc_media_player_event_manager(libvlc_mp);
foreach (const libvlc_event_e &event, events) {
libvlc_event_attach(libvlc_eventManager, event, handleEvents, this);
}
事件处理函数如下
void VlcPlayer::handleEvents(const libvlc_event_t *event, void *userData)
{
VlcPlayer* player = static_cast<VlcPlayer*>(userData);
switch (event->type) {
// 播放状态改变
case libvlc_MediaPlayerOpening:{
qDebug()<<"libvlc_MediaPlayerOpening"<<endl;
break;
}
case libvlc_MediaPlayerBuffering:{
break;
}
case libvlc_MediaPlayerPlaying: {
break;
}
case libvlc_MediaPlayerPaused: {
break;
}
case libvlc_MediaPlayerStopped: {
//当 libvlc_media_player_stop(libvlc_mp); 被调用才会触发该信号
break;
}
case libvlc_MediaPlayerEncounteredError: {
break;
}
// 时长改变时获取一次总时长
case libvlc_MediaPlayerLengthChanged: {
break;
}
// 播放时间改变
case libvlc_MediaPlayerTimeChanged: {
//播放时间是一直在变的
break;
}
// 播放位置改变
case libvlc_MediaPlayerPositionChanged: {
//播放位置是一直在变的,个人认为等同 libvlc_MediaPlayerTimeChanged
break;
}
case libvlc_MediaPlayerEndReached:
//当视频播放结束时触发该信号
break;
default:
break;
}
}
四、了解vlc辅助类API
libvlc_audio_set_volume
LIBVLC_API int libvlc_audio_set_volume( libvlc_media_player_t *p_mi, int i_volume );
设置播放声音，i_volume值为 0~100
libvlc_media_player_set_position
LIBVLC_API void libvlc_media_player_set_position( libvlc_media_player_t *p_mi, float f_pos );
设置播放位置，这个位置不是随便设置的,f_pos 0~1
void VlcPlayer::setPosition(float position)
{
float length = libvlc_media_player_get_length(libvlc_mp);
libvlc_media_player_set_position(libvlc_mp,position/length);
}
libvlc_media_player_get_length
LIBVLC_API libvlc_time_t libvlc_media_player_get_length( libvlc_media_player_t *p_mi );
获取视频的长度，在设置播放位置有用到，很实用
libvlc_video_get_width/libvlc_video_get_height
LIBVLC_DEPRECATED LIBVLC_API
int libvlc_video_get_width( libvlc_media_player_t *p_mi );
LIBVLC_DEPRECATED LIBVLC_API
int libvlc_video_get_height( libvlc_media_player_t *p_mi );
获取视频长宽,看着也就是数据，但是如果你要获取视频的每一帧保存就需要获取视频的长宽
五、封装vlc播放器对象
vlcplayer.h
#ifndef PLAYER_H
#define PLAYER_H
#include <QObject>
#include <QWidget>
#include "vlc/vlc.h"
#include "vlc/libvlc.h"
class VlcPlayer : public QObject
{
Q_OBJECT
public:
explicit VlcPlayer(QObject *parent = nullptr);
signals:
void signal_MediaPlayerPlaying();
void signal_MediaPlayerStopped();
signals:
void signal_media_player_time(int curtime);
private:
void MediaPlayerEncounteredError();
public:
bool setURL(QString& URL);
void setPosition(float position);
void media_play();
void media_pause();
void media_stop();
int media_get_length();
void media_set_voice(int value);
void set_media_player_hwnd(QWidget* widget);
libvlc_state_t get_media_player_state();
private:
// 订阅事件
void attachEvents();
static void handleEvents(const libvlc_event_t* event, void* userData);
private:
libvlc_event_manager_t* libvlc_eventManager; /*事件管理器*/
libvlc_instance_t* libvlc_inst; /*vlc播放器实例*/
libvlc_media_player_t* libvlc_mp; /*vlc播放器*/
libvlc_media_t* libvlc_m; /*音视频文件*/
libvlc_state_t libvlc_state; /*播放状态*/
QWidget* libvlc_mainWindow; /*播放器窗口*/
WId libvlc_WId; /*窗口*/
QString libvlc_url; /*播放的URL*/
/*时间相关*/
int m_timeLength;
};
#endif // PLAYER_H
vlcplayer.cpp
#include "vlcplayer.h"
#include <QDebug>
#include <QThread>
#include <windows.h>
VlcPlayer::VlcPlayer(QObject *parent) : QObject(parent)
{
libvlc_eventManager = NULL;
libvlc_inst = NULL;
libvlc_mp = NULL;
libvlc_m = NULL;
libvlc_state = libvlc_NothingSpecial; /*播放状态*/
libvlc_mainWindow = NULL;
libvlc_WId = 0;
}
bool VlcPlayer::setURL(QString &URL)
{
if(URL.isEmpty())
{
qDebug()<<"URL is Empty"<<endl;
return false;
}
libvlc_url = URL;
return true;
}
void VlcPlayer::setPosition(float position)
{
float length = libvlc_media_player_get_length(libvlc_mp);
libvlc_media_player_set_position(libvlc_mp,position/length);
}
void VlcPlayer::media_play()
{
if (libvlc_state != libvlc_NothingSpecial) {
qDebug()<<"Media is playing now."<<endl;
return;
}
const char* version;
version = libvlc_get_version();
qDebug()<<"version:"<<version<<endl;
/* Load the VLC engine */
const char* const vlc_args[] = {
"--demux=h264",
"--ipv4",
"--no-prefer-system-codecs",
"--rtsp-caching=300",
"--network-caching=500", //网络额外缓存值 (ms)
"--rtsp-frame-buffer-size=10000000",
"--rtsp-tcp", //RTSP采用TCP传输方式
};
/* Create a new item */
if (libvlc_url.contains("rtsp")) {
//URL播放rtsp网络流
/* Load the VLC engine */
libvlc_inst = libvlc_new(sizeof(vlc_args) / sizeof(vlc_args[0]), vlc_args);
if (libvlc_inst == NULL)
{
qDebug()<<"libvlc_new error"<<endl;
return;
}
libvlc_m = libvlc_media_new_location(libvlc_inst, libvlc_url.toStdString().c_str());
if (libvlc_m == NULL)
{
qDebug()<<"error :libvlc_media_new_location error"<<endl;
return;
}
}
else
{
libvlc_inst = libvlc_new(0, NULL);
if (libvlc_inst == NULL)
{
qDebug()<<"libvlc_new error"<<endl;
return;
}
//本地播放视频流
libvlc_m = libvlc_media_new_path(libvlc_inst, libvlc_url.toStdString().c_str());
static int index = 0;
qDebug()<<"URL["<<index++<<"]:"<<libvlc_url.toStdString().c_str();
if (libvlc_m == NULL)
{
qDebug()<<"libvlc_media_new_path error";
media_stop();
return;
}
}
/* Create a media player playing environement */
libvlc_mp = libvlc_media_player_new_from_media(libvlc_m);
/*添加事件*/
attachEvents();
/* No need to keep the media now */
libvlc_media_release(libvlc_m);
//on windows
if (libvlc_mainWindow != NULL){
Sleep(45);
libvlc_WId = libvlc_mainWindow->winId();
libvlc_media_player_set_hwnd(libvlc_mp, (void*)libvlc_WId);
}
else
{
Sleep(45);
}
/* play the media_player */
libvlc_media_player_play(libvlc_mp);
libvlc_state = libvlc_Playing;
}
void VlcPlayer::media_pause()
{
libvlc_state = libvlc_media_player_get_state(libvlc_mp);
if (libvlc_state == libvlc_Playing) {
if (libvlc_media_player_can_pause(libvlc_mp))
{
libvlc_media_player_set_pause(libvlc_mp, 1);
libvlc_state = libvlc_Paused;
}
}
else if (libvlc_state == libvlc_Paused) {
libvlc_media_player_set_pause(libvlc_mp, 0);
libvlc_state = libvlc_Playing;
}
}
void VlcPlayer::media_stop()
{
if (libvlc_mp != NULL) {
libvlc_media_player_stop(libvlc_mp);
libvlc_media_player_release(libvlc_mp);
libvlc_release(libvlc_inst);
libvlc_mp = NULL;
libvlc_m = NULL;
libvlc_eventManager = NULL;
libvlc_inst = NULL; /*vlc播放器实例*/
}
libvlc_state = libvlc_NothingSpecial;
}
int VlcPlayer::media_get_length()
{
return m_timeLength;
}
void VlcPlayer::media_set_voice(int value)
{
if(value < 0)
return;
if(libvlc_mp!=NULL){
libvlc_audio_set_volume(libvlc_mp,value);
}
}
void VlcPlayer::MediaPlayerEncounteredError()
{
qDebug()<<"================播放错误=================="<<endl;
}
void VlcPlayer::set_media_player_hwnd(QWidget* widget)
{
libvlc_mainWindow = widget;
}
libvlc_state_t VlcPlayer::get_media_player_state()
{
return libvlc_state;
}
void VlcPlayer::attachEvents()
{
// 事件列表
QList<libvlc_event_e> events;
events << libvlc_MediaPlayerOpening
<< libvlc_MediaPlayerBuffering
<< libvlc_MediaPlayerPlaying
<< libvlc_MediaPlayerPaused
<< libvlc_MediaPlayerStopped
<< libvlc_MediaPlayerEncounteredError
<< libvlc_MediaPlayerMuted
<< libvlc_MediaPlayerUnmuted
<< libvlc_MediaPlayerAudioVolume
<< libvlc_MediaPlayerLengthChanged
<< libvlc_MediaPlayerTimeChanged
<< libvlc_MediaPlayerPositionChanged
<< libvlc_MediaPlayerEndReached;
// 订阅事件
libvlc_eventManager = libvlc_media_player_event_manager(libvlc_mp);
foreach (const libvlc_event_e &event, events) {
libvlc_event_attach(libvlc_eventManager, event, handleEvents, this);
}
}
void VlcPlayer::handleEvents(const libvlc_event_t *event, void *userData)
{
VlcPlayer* player = static_cast<VlcPlayer*>(userData);
switch (event->type) {
// 播放状态改变
case libvlc_MediaPlayerOpening:{
qDebug()<<"libvlc_MediaPlayerOpening"<<endl;
break;
}
case libvlc_MediaPlayerBuffering:{
break;
}
case libvlc_MediaPlayerPlaying: {
emit player->signal_MediaPlayerPlaying();
break;
}
case libvlc_MediaPlayerPaused: {
break;
}
case libvlc_MediaPlayerStopped: {
//当 libvlc_media_player_stop(libvlc_mp); 被调用才会触发该信号
qDebug()<< "播放结束" <<endl;
break;
}
case libvlc_MediaPlayerEncounteredError: {
player->MediaPlayerEncounteredError();
break;
}
// 时长改变时获取一次总时长
case libvlc_MediaPlayerLengthChanged: {
player->m_timeLength = libvlc_media_player_get_length(player->libvlc_mp);
break;
}
// 播放时间改变
case libvlc_MediaPlayerTimeChanged: {
//播放时间是一直在变的
int curtime =libvlc_media_player_get_time(player->libvlc_mp);
player->signal_media_player_time(curtime);
break;
}
// 播放位置改变
case libvlc_MediaPlayerPositionChanged: {
//播放位置是一直在变的,个人认为等同 libvlc_MediaPlayerTimeChanged
break;
}
case libvlc_MediaPlayerEndReached:
//当视频播放结束时触发该信号
emit player->signal_MediaPlayerStopped();
break;
default:
break;
}
}
基本封装完成，具体使用看源代码实例程序，实例程序运行如下
