VLC主要结构体

对于Android端客户端，主要是有三个c层的结构体持有数据，是LibVLC.java对应的libvlc_instance_t。Media.java对应的libvlc_media_t，以及播放器对应的libvlc_media_player_t。
三个层次分别对应播放器的配置参数，多媒体信息以及播放器状态
下面简要介绍一下三部分关系，

libvlc_instance_t * libvlc_new( int argc, const char *const *argv )
{
    libvlc_int_t *p_libvlc_int = libvlc_InternalCreate();
   
    libvlc_InternalInit( p_libvlc_int, argc + 1, my_argv )
    
    return p_new;
}

/**
 * Initialize a libvlc instance
 * This function initializes a previously allocated libvlc instance:
 *  - CPU detection
 *  - gettext initialization
 *  - message queue, module bank and playlist initialization
 *  - configuration and commandline parsing
 */
int libvlc_InternalInit( libvlc_int_t *p_libvlc, int i_argc,
                         const char *ppsz_argv[] )
{
    libvlc_priv_t *priv = libvlc_priv (p_libvlc);
    char        *psz_val;
    int          i_ret = VLC_EGENERIC;

    /*
     * Initialize the module bank and load the core config only.
     * 加载core这个模块，
     */
    module_InitBank ();

    /*
     * Load plugin data into the module bank.
     * We need to do this here such that option sets from plugins are added to
     * the config system in order that full commandline argument parsing and
     * saved settings handling can function properly.
     * 对于Android 这是通过shell脚本把需要的modue写完，最终注册打需要的二叉树上的，
     */
    module_LoadPlugins (p_libvlc);

    /*
     * Fully process command line settings.
     * Results are stored as runtime state within `p_libvlc` object variables.
     */
    int vlc_optind;
    if( config_LoadCmdLine( p_libvlc, i_argc, ppsz_argv, &vlc_optind ) )
        goto error;

		//根据平台加载Log日志
    vlc_LogInit(p_libvlc);

    return VLC_SUCCESS;
}

/**
 * Init bank
 *
 * Creates a module bank structure which will be filled later
 * on with all the modules found.
 */
void module_InitBank (void)
{

        /* Fills the module bank structure with the core module infos.
         * This is very useful as it will allow us to consider the core
         * library just as another module, and for instance the configuration
         * options of core will be available in the module bank structure just
         * as for every other module. 
				*VLC_MODULE_ENTRY(core) =========> vlc_entry__core 这是libvlc-module.c中vlc_module_begin预处理出来的方法。方法体就是声明的内容
				*/
        vlc_plugin_t *plugin = module_InitStatic(VLC_MODULE_ENTRY(core));
        if (likely(plugin != NULL))
            vlc_plugin_store(plugin);
        config_SortConfig ();

    /* We do retain the module bank lock until the plugins are loaded as well.
     * This is ugly, this staged loading approach is needed: LibVLC gets
     * some configuration parameters relevant to loading the plugins from
     * the core (builtin) module. The module bank becomes shared read-only data
     * once it is ready, so we need to fully serialize initialization.
     * DO NOT UNCOMMENT the following line unless you managed to squeeze
     * module_LoadPlugins() before you unlock the mutex. */
    /*vlc_mutex_unlock (&modules.lock);*/
}


/**
 * Registers a statically-linked plug-in.
 */
static vlc_plugin_t *module_InitStatic(vlc_plugin_cb entry)
{
    /* Initializes the statically-linked library */
    vlc_plugin_t *lib = vlc_plugin_describe (entry);
    return lib;
}

vlc_plugin_t *vlc_plugin_describe(vlc_plugin_cb entry)
{
    vlc_plugin_t *plugin = vlc_plugin_create();
    //调用vlc_module_begin中的方法体中的内容
    entry(vlc_plugin_desc_cb, plugin)
    return plugin;
}

主要的core初始化大概就这些，下面分析一下media的初始化。主要是通过

void
Java_org_videolan_libvlc_Media_nativeNewFromPath(JNIEnv *env, jobject thiz,
                                                 jobject libVlc, jstring jpath)
{
    Media_nativeNewFromCb(env, thiz, libVlc, jpath, libvlc_media_new_path);
}

最关键的是通过libvlc_media_new_path，拿到libvlc_media_t

// Create a media for a certain file path
libvlc_media_t *libvlc_media_new_path(const char *path)
{
    char *mrl = vlc_path2uri( path, NULL );
    if( unlikely(mrl == NULL) )
    {
        libvlc_printerr( "%s", vlc_strerror_c(errno) );
        return NULL;
    }

    libvlc_media_t *m = libvlc_media_new_location(mrl);
    free( mrl );
    return m;
}

// Create a media with a certain given media resource location
libvlc_media_t *libvlc_media_new_location(const char * psz_mrl)
{
    input_item_t * p_input_item;
    libvlc_media_t * p_md;

    p_input_item = input_item_New( psz_mrl, NULL );

    if (!p_input_item)
    {
        libvlc_printerr( "Not enough memory" );
        return NULL;
    }

    p_md = libvlc_media_new_from_input_item( p_input_item );

    /* The p_input_item is retained in libvlc_media_new_from_input_item */
    input_item_Release( p_input_item );

    return p_md;
}

具体不详细介绍。播放器流程这里就不再详细介绍，下一篇介绍。

后记