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This option allows the videomixer2 element to output a valid alpha channel when the inputs contain a valid alpha channel. This allows mixing to occur in multiple stages serially. The following pipeline shows an example of such a pipeline: gst-launch videotestsrc background-color=0x000000 pattern=ball ! video/x-raw-yuv,format=\(fourcc\)AYUV ! videomixer2 background=transparent name=mix1 ! videomixer2 name=mix2 ! ffmpegcolorspace ! autovideosink videotestsrc ! video/x-raw-yuv,format=\(fourcc\)AYUV ! mix2. The first videotestsrc in this pipeline creates a moving ball on a transparent background. It is then passed to the first videomixer2. Previously, this videomixer2 would have forced the alpha channel to 1.0 and given a background of checker, black, or white to the stream. With this patch, however, you can now specify the background as transparent, and the alpha channel of the input will be preserved. This allows for further mixing downstream, as is shown in the above pipeline where the a second videomixer2 is used to mix in a background of an smpte videotestsrc. So the result is a ball hovering over the smpte test source. This could, of course, have been accomplished with a single mixer element, but staged mixing is useful when it is not convenient to mix all video at once (e.g. a pipeline where a foreground and background bin exist and are mixed at the final output, but the foreground bin needs an internal mixer to create transitions between clips). Fixes bug #639994. |
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| .. | ||
| blend.c | ||
| blend.h | ||
| blendorc-dist.c | ||
| blendorc-dist.h | ||
| blendorc.orc | ||
| gstcollectpads2.c | ||
| gstcollectpads2.h | ||
| Makefile.am | ||
| README | ||
| videomixer.c | ||
| videomixer.h | ||
| videomixer.vcproj | ||
| videomixer2.c | ||
| videomixer2.h | ||
| videomixer2pad.h | ||
| videomixerpad.h | ||
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