gstreamer/gst/videomixer/README

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
A plugin to add an alpha channel to I420 video. Can optionally do chroma keying. Original commit message from CVS: * configure.ac: * gst/alpha/Makefile.am: * gst/alpha/gstalpha.c: (gst_alpha_method_get_type), (gst_alpha_get_type), (gst_alpha_base_init), (gst_alpha_class_init), (gst_alpha_init), (gst_alpha_set_property), (gst_alpha_get_property), (gst_alpha_sink_link), (gst_alpha_add), (gst_alpha_chroma_key), (gst_alpha_chain), (gst_alpha_change_state), (plugin_init): A plugin to add an alpha channel to I420 video. Can optionally do chroma keying. * gst/multipart/Makefile.am: * gst/multipart/multipart.c: (plugin_init): * gst/multipart/multipartdemux.c: (gst_multipart_demux_base_init), (gst_multipart_demux_class_init), (gst_multipart_demux_init), (gst_multipart_demux_finalize), (gst_multipart_demux_handle_event), (gst_multipart_find_pad_by_mime), (gst_multipart_demux_chain), (gst_multipart_demux_change_state), (gst_multipart_demux_plugin_init): * gst/multipart/multipartmux.c: (gst_multipart_mux_get_type), (gst_multipart_mux_base_init), (gst_multipart_mux_class_init), (gst_multipart_mux_get_sink_event_masks), (gst_multipart_mux_init), (gst_multipart_mux_sinkconnect), (gst_multipart_mux_pad_link), (gst_multipart_mux_pad_unlink), (gst_multipart_mux_request_new_pad), (gst_multipart_mux_handle_src_event), (gst_multipart_mux_next_buffer), (gst_multipart_mux_compare_pads), (gst_multipart_mux_queue_pads), (gst_multipart_mux_loop), (gst_multipart_mux_get_property), (gst_multipart_mux_set_property), (gst_multipart_mux_change_state), (gst_multipart_mux_plugin_init): A Multipart demuxer/muxer. Not sure if it violates specs. Used to send multipart jpeg images to a browser. * gst/videobox/Makefile.am: * gst/videobox/README: * gst/videobox/gstvideobox.c: (gst_video_box_fill_get_type), (gst_video_box_get_type), (gst_video_box_base_init), (gst_video_box_class_init), (gst_video_box_init), (gst_video_box_set_property), (gst_video_box_get_property), (gst_video_box_sink_link), (gst_video_box_i420), (gst_video_box_ayuv), (gst_video_box_chain), (gst_video_box_change_state), (plugin_init): Crops or adds borders around an image. can do alpha channel borders as well. * gst/videomixer/Makefile.am: * gst/videomixer/README: * gst/videomixer/videomixer.c: (gst_videomixer_pad_get_type), (gst_videomixer_pad_base_init), (gst_videomixer_pad_class_init), (gst_videomixer_pad_get_sink_event_masks), (gst_videomixer_pad_get_property), (gst_videomixer_pad_set_property), (gst_videomixer_pad_sinkconnect), (gst_videomixer_pad_link), (gst_videomixer_pad_unlink), (gst_videomixer_pad_init), (gst_video_mixer_background_get_type), (gst_videomixer_get_type), (gst_videomixer_base_init), (gst_videomixer_class_init), (gst_videomixer_init), (gst_videomixer_request_new_pad), (gst_videomixer_handle_src_event), (gst_videomixer_blend_ayuv_i420), (gst_videomixer_fill_checker), (gst_videomixer_fill_color), (gst_videomixer_fill_queues), (gst_videomixer_blend_buffers), (gst_videomixer_update_queues), (gst_videomixer_loop), (gst_videomixer_get_property), (gst_videomixer_set_property), (gst_videomixer_change_state), (plugin_init): Generic video mixer plugin, can handle multiple inputs all with different framerates and video sizes. Is fully alpha channel aware. 2004-05-28 18:01:34 +00:00			`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`