Image Depth

Usage

Starting with version 2.0, you can simply specify which pixel bit depth you want to use when starting a session:

xpra start --pixel-depth=30

Support for each subcommand:

• "xpra start" supports bit depths 16,24 and 30
• "xpra start-desktop" supports 8,16,24 and 30
• "xpra attach" supports 16,24,30,48 (with xpra version 2.1 or later only)

Testing that high bit depth is in use can be tricky, for that we provide a test application: #1553.

Limitations

• the operating system and display must be configured for deep colour support
• transparency is supported in 24-bit mode, which is in effect a 32-bit mode
• with versions older than 4.1, 30-bit rendering is only supported in the opengl enabled client, and only the rgb encoding will preserve high bit depth
• 16-bit mode has no real native encoders and so the pixels are often upsampled to 24-bit before compression which is wasteful
• 8-bit mode is not optimized
• see wiki/Colourspace

Links

• #1445: 8-bit server support
• #1315: 16-bit server support
• #909: 30-bit server support
• #1309, #2839: 30-bit client support
• #2828: 30-bit opengl rendering of video output
• #1584: HDR / Deep Color support in X11
• ​10-bit Color Visual Support Lands In Mesa

Codec support for 10 bit per channel (aka 30 bit):

• #1441: EXR codec
• #1310: vpx
• #1308: nvenc
• #1462: x264