On Fri, Aug 6, 2010 at 18:43, Martin Langhoff <[email protected]> wrote: > On Fri, Aug 6, 2010 at 12:30 PM, Richard A. Smith <[email protected]> wrote: >> Whats the qualifications on that? I assume its raw RGB video? > > No, it's compressed vid + uncompressed audio to be stitched later. > > I have a confession to make: Many years ago I worked in video mixing > with mid-range gear (avid and media100, I *don't* miss you) and with > cheapskates PC-based rigs (which where hell on wheels compared to avid > and media100). > > My take is that our CPU is perfectly capable of capturing and > compressing vid and audio and putting it down to disk, even on a > 2MB/s-capable disk, helped a bit by (limited) linux kernel buffering. > Most importantly, we need to capture audio + vid together, or at least > timestamp them together. Otherwise drift is inevitable. > > I also think our vm.dirty_* settings are wrong and likely causing our > current fill-buffer-and-stutter behaviour. We are using the defaults > and those are for spinning harddrives, with a significant cost to > spinning up the disk on a laptop -- hence long expire_centisecs and > writeback_centisecs and the assumption that once you've started > writing, it'll be written out fast. We have zero seek costs, zero > "spin disk up" costs, but slowish writes -- we have to start writing > buffers out ASAP.
I had also had the impression for some time that some knobs in the kernel could have been better tuned for the XO-1 and the actual workload. Regards, Tomeu > But that's my (naive?) take. I haven't delved into the gstreamer madness. > > > m > -- > [email protected] > [email protected] -- School Server Architect > - ask interesting questions > - don't get distracted with shiny stuff - working code first > - http://wiki.laptop.org/go/User:Martinlanghoff > _______________________________________________ > Devel mailing list > [email protected] > http://lists.laptop.org/listinfo/devel > _______________________________________________ Devel mailing list [email protected] http://lists.laptop.org/listinfo/devel
