Is there any way to render low size file rgba quicktime mov ?
You can render it as a H264 file. Render the first file with the RGB and name it like so: “filename.mov”. Then render a second file with the alpha channel and name it like so: “filename_A.mov”. Caspar will automatically play them as one, if you play the first file.
Depending on the content QT animation files can be tiny. You can also use ProRes with alpha. Another option is using webm VP8 or VP9 with alpha in HTML.