VLC1.2 播放视频迟滞卡

用libvlc 提供的示例，用1080p播放本事是720p的视频，会有卡住的现象。

后改用32位播放后正常。（R,G,B的掩码需要适当调换。我在ubuntu上编译两个项目，掩码值都需要调换，不知道为什么）

SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_SRCCOLORKEY | SDL_SRCALPHA, w,h, 32, 0xff0000, 0xff00, 0x00ff, 0);

SDL_CreateRGBSurface(SDL_HWSURFACE | SDL_ASYNCBLIT | SDL_SRCCOLORKEY | SDL_SRCALPHA, w, h,32, 0x00ff, 0xff00, 0xff0000, 0);

示例代码：

#include <stdio.h>
#include <stdint.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>

#include <SDL/SDL.h>
#include <SDL/SDL_mutex.h>

#include <vlc/vlc.h>


#define WIDTH 1920
#define HEIGHT 1080

#define VIDEOWIDTH 1920
#define VIDEOHEIGHT 1080

struct ctx
{
    SDL_Surface *surf;
    SDL_mutex *mutex;
};

static void *lock(void *data, void **p_pixels)
{
    struct ctx *ctx = data;

    SDL_LockMutex(ctx->mutex);
    SDL_LockSurface(ctx->surf);
    *p_pixels = ctx->surf->pixels;
    return NULL; /* picture identifier, not needed here */
}

static void unlock(void *data, void *id, void *const *p_pixels)
{
    struct ctx *ctx = data;
/*

     VLC just rendered the video, but we can also render stuff
    uint16_t *pixels = *p_pixels;
    int x, y;

    for(y = 10; y < 40; y++)
        for(x = 10; x < 40; x++)
            if(x < 13 || y < 13 || x > 36 || y > 36)
                pixels[y * VIDEOWIDTH + x] = 0xffff;
            else
                pixels[y * VIDEOWIDTH + x] = 0x0;
*/

    SDL_UnlockSurface(ctx->surf);
    SDL_UnlockMutex(ctx->mutex);

    assert(id == NULL); /* picture identifier, not needed here */
}

static void display(void *data, void *id)
{
    /* VLC wants to display the video */
    (void) data;
    assert(id == NULL);
}

int vlc_main(int argc, char *argv[])
{
    libvlc_instance_t *libvlc;
    libvlc_media_t *m;
    libvlc_media_player_t *mp;
    char const *vlc_argv[] =
    {
        "--no-audio", /* skip any audio track */
        "--no-xlib", /* tell VLC to not use Xlib */
    };
    int vlc_argc = sizeof(vlc_argv) / sizeof(*vlc_argv);

    SDL_Surface *screen, *empty;
    SDL_Event event;
    SDL_Rect rect;
    int done = 0, action = 0, pause = 0, n = 0;

    struct ctx ctx;
/*

    if(argc < 2)
    {
        printf("Usage: %s <filename>
", argv[0]);
        return EXIT_FAILURE;
    }
*/

    /*
     *  Initialise libSDL
     */
    if(SDL_Init(SDL_INIT_VIDEO | SDL_INIT_EVENTTHREAD) == -1)
    {
        printf("cannot initialize SDL
");
        return EXIT_FAILURE;
    }

    empty = SDL_CreateRGBSurface(SDL_SWSURFACE, VIDEOWIDTH, VIDEOHEIGHT,
                                 32, 0, 0, 0, 0);
    ctx.surf = SDL_CreateRGBSurface(SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_SRCCOLORKEY|SDL_SRCALPHA, VIDEOWIDTH, VIDEOHEIGHT,
                                    32, 0x00ff, 0xff00, 0xff0000, 0);

    ctx.mutex = SDL_CreateMutex();

    int options = SDL_ANYFORMAT | SDL_HWSURFACE | SDL_DOUBLEBUF;

    screen = SDL_SetVideoMode(WIDTH, HEIGHT, 0, options);
    if(!screen)
    {
        printf("cannot set video mode
");
        return EXIT_FAILURE;
    }

    /*
     *  Initialise libVLC
     */
    libvlc = libvlc_new(vlc_argc, vlc_argv);
    m = libvlc_media_new_path(libvlc, "./test.mp4");
    mp = libvlc_media_player_new_from_media(m);
    libvlc_media_release(m);

    libvlc_video_set_callbacks(mp, lock, unlock, display, &ctx);
    libvlc_video_set_format(mp, "RV32", VIDEOWIDTH, VIDEOHEIGHT, VIDEOWIDTH*4);
    libvlc_media_player_play(mp);

    /*
     *  Main loop
     */
    rect.w = 0;
    rect.h = 0;

    while(!done)
    {
        action = 0;

        /* Keys: enter (fullscreen), space (pause), escape (quit) */
        while( SDL_PollEvent( &event ) )
        {
            switch(event.type)
            {
            case SDL_QUIT:
                done = 1;
                break;
            case SDL_KEYDOWN:
                action = event.key.keysym.sym;
                break;
            }
        }

        switch(action)
        {
        case SDLK_ESCAPE:
            done = 1;
            break;
        case SDLK_RETURN:
            options ^= SDL_FULLSCREEN;
            screen = SDL_SetVideoMode(WIDTH, HEIGHT, 0, options);
            break;
        case ' ':
            pause = !pause;
            break;
        }

//        rect.x = (int)((1. + .5 * sin(0.03 * n)) * (WIDTH - VIDEOWIDTH) / 2);
//        rect.y = (int)((1. + .5 * cos(0.03 * n)) * (HEIGHT - VIDEOHEIGHT) / 2);
        rect.x=0;
        rect.y=0;

        if(!pause)
            n++;

        /* Blitting the surface does not prevent it from being locked and
         * written to by another thread, so we use this additional mutex. */
        SDL_LockMutex(ctx.mutex);
        SDL_BlitSurface(ctx.surf, NULL, screen, &rect);
        SDL_UnlockMutex(ctx.mutex);

        SDL_Flip(screen);
        SDL_Delay(0);

        SDL_BlitSurface(empty, NULL, screen, &rect);
    }

    /*
     * Stop stream and clean up libVLC
     */
    libvlc_media_player_stop(mp);
    libvlc_media_player_release(mp);
    libvlc_release(libvlc);

    /*
     * Close window and clean up libSDL
     */
    SDL_DestroyMutex(ctx.mutex);
    SDL_FreeSurface(ctx.surf);
    SDL_FreeSurface(empty);

    SDL_Quit();

    return 0;
}