无法在 SDL_Surface 上显示 YUV 叠加 [英] Cannot display YUV Overlay on SDL_Surface

问题描述

我想通过隐藏其 SDL 视频播放器窗口来修改 ffplay.相反，我想将叠加层作为逐个像素的位图抓取，以便在我的程序中的其他地方使用.

I want to modify ffplay by hiding its SDL video player window. Rather, I want to grab the overlay as pixel-by-pixel bitmaps to be used elsewhere in my program.

现在ffplay可以简化如下:

1. 从SDL_SetVideoMode()

从SDL_CreateYUVOverlay()创建SDL_Overlay *bmp并将其与screen

重复直到视频结束

解码电影帧并填充 bmp

Decode movie frames and populate bmp

使用 SDL_DisplayYUVOverlay()

根据这篇文章的提示，我已将第 1 步替换为如下所示:

Following hints from this article, I have replaced Step 1 as below:

/* Don't want video player window showing on screen
* int flags = SDL_HWSURFACE|SDL_ASYNCBLIT|SDL_HWACCEL;
* screen = SDL_SetVideoMode(w, h, 24, flags);
*/
Uint32 rmask, gmask, bmask, amask;
#if SDL_BYTEORDER == SDL_BIG_ENDIAN
rmask = 0xff000000;
gmask = 0x00ff0000;
bmask = 0x0000ff00;
amask = 0x00000000;
#else
rmask = 0x000000ff;
gmask = 0x0000ff00;
bmask = 0x00ff0000;
amask = 0x00000000;
#endif
screen = SDL_CreateRGBSurface(SDL_SWSURFACE, w, h, 24, rmask, gmask, bmask, amask);

和步骤 4 为

SDL_DisplayYUVOverlay(bmp, &rect);
SDL_SaveBMP(screen, filenameN); N++;

问题:如果我只修改第 4 步，位图文件将得到正确保存，这正是我想要的，除了视频播放窗口是可见的.另一方面，如果我也修改步骤 2，则窗口成功隐藏，位图全部变黑.

Issue: If I modify only Step 4, the bitmap files are getting saved properly which is what I want, except that the video playing window is visible. On the other hand, if I modify Step 2 as well, the window gets successfully hidden the bitmaps are all blacked out.

我是 SDL 的新手，所以除了解决方案之外，解释为什么我的方法不起作用会很有帮助.

I am new to SDL, so apart from just the solution, an explanation on why my approach does not work will be helpful.

推荐答案

使用 SDL_putenv("SDL_VIDEODRIVER=dummy"); 使用 虚拟 视频驱动程序，不产生输出.

Use SDL_putenv("SDL_VIDEODRIVER=dummy"); to use the dummy video driver, which produces no output.

这篇关于无法在 SDL_Surface 上显示 YUV 叠加的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！