On 4 March 2013 09:00, Antoine Martin <[email protected]> wrote: > Hi Nick, > > xpra is a compositing window manager, and AFAIK this requires 24bpp or > higher. I've tried launching Xvfb/Xdummy with 8bpp and Composite gets > turned off. The -pixdepths switch does not help here. FYI: xpra seems to > crash rather than exit gracefully, but that's another problem. > > As for achieving bandwidth savings by reducing the colour depth, x264 > and vpx encodings use colour subsampling when the quality is lowered > (switching from 4:4:4 to 4:2:2 and 4:2:0), this is in the chroma+luma > space rather than plain RGB, but it does save about 50% on image size. > Also note that newer encodings (x264, webp, etc) are vastly superior to > the encodings found in VNC, so the bandwidth usage should already be > much lower (even without colour subsampling).
Alright, that makes sense. My gnome-terminal data transfer showed as 420Mbytes for around 6 hours of operation (using x264). I'll have a go at tuning the quality some more and extend the time between full window refreshes. I wonder if there's some efficiency to be gained by pre-processing the image before compression (at the expense of quality) -- perhaps by masking out the bottom 3 bits of R, G and B values so that the compressors don't have to try to handle subtle colour variations. > > If you find that the quality/bandwidth/framerate/latency isn't good > enough for you use case, let me know - it is quite possible that recent > versions have focused a little bit too much on the LAN usage scenario.. It's not great at the moment -- it can take 2-3 seconds to switch a tab in gnome-terminal, for example. But I'd rather ensure that I've exhausted my client option settings first. Regards, Nick > > > On 03/03/2013 07:26 PM, Nick Burrett wrote: >> Hi, >> >> Is it possible to reduce the colour depth client side when performing >> xpra attach? >> >> I'm attempting to use xpra over a 3G modem link where the X server is >> 140ms away. For a while, I've been using a VNC setup in exactly this >> way and found that reducing the colour from 24bits to 8bits had a >> considerable impact on usability. >> >> Xvfb has a -pixdepths option, which appears to be a list of supported >> colour depths. I just would like to get the client to allow the >> choice to be determined at connection time. >> >> Regards, >> >> Nick. >> _______________________________________________ >> shifter-users mailing list >> [email protected] >> http://lists.devloop.org.uk/mailman/listinfo/shifter-users >> > > _______________________________________________ > shifter-users mailing list > [email protected] > http://lists.devloop.org.uk/mailman/listinfo/shifter-users _______________________________________________ shifter-users mailing list [email protected] http://lists.devloop.org.uk/mailman/listinfo/shifter-users
