##
Proxies with Alpha channel

Next are some examples of tested and working configurations that maintain the alpha channel:

    Proxy #1
    	Scale factor: 1/4
    	Rescaled to project size (FFMPEG only) = unchecked
    	File Format: FFMPEG | qt
    	Video Preset-->
    		Compression: png.qt
    		Bitrate: 0
    		Quality: -1
    		Pixels: rgba (or rgba64be)

    Proxy #2
    	Scale factor: 1/4
    	Rescaled to project size (FFMPEG only) = unchecked
    	File Format: FFMPEG | qt
    	Video Preset-->
    		Compression: magicyuv.qt
    		Bitrate: 0
    		Quality: -1
    		Pixels: yuva444p

    Proxy #3
    	Scale factor: 1/4
    	Rescaled to project size (FFMPEG only) = unchecked
    	File Format: FFMPEG | qt
    	Video Preset-->
    		Compression: openjpeg.qt
    		Bitrate: 0
    		Quality: -1
    		Pixels: yuva420p

    Proxy #4
    	Scale factor: 1/4
    	Rescaled to project size (FFMPEG only) = unchecked
    	File Format: FFMPEG | pro
    	Video Preset-->
    		Compression: prores_4444.pro
    		prores_4444xq.pro
    		Bitrate: 0
    		Quality: -1
    		Pixels: yuva444p10le

    Proxy #5
    	Scale factor: 1/4
    	Rescaled to project size (FFMPEG only) = unchecked
    	File Format: FFMPEG | mkv
    	Video Preset-->
    		Compression: user_ffvhuff.mkv
    		Bitrate: 0
    		Quality: -1
    		Pixels: yuva4--p
    				   yuva4--p--le