| Video Mixer |
| ----------- |
| |
| A generice video mixer, it blends the ayuv buffers from all pads onto |
| a new buffer. The new buffer has by default a checkerboard pattern but |
| its color can be changed with a property. |
| The mixer can mix streams with different framerates and video sizes. It |
| uses the duration value of the buffer to schedule the rendering of the |
| buffers. For streams with a different resoltion than the final output |
| resolution one can specify the position of the top left corner where this |
| image should be placed with the pad properties xpos and ypos. |
| The overall alpha value of a stream can also be specified with a pad |
| property. |
| By default, the streams are blended in the order that the pads were |
| requested from the element. This can be overridden by changing the |
| zorder pad property of the stream, a stream with lower zorder gets |
| drawn first. |
| |
| |
| TODO |
| ---- |
| |
| - really implement zorder |
| - take I420 yuv as well |
| - output AYUV if possible. |
| - implement different blend modes, some code is already done |
| - use filter caps on srcpad to decide on the final output size |
