On Fri, 21 Nov 2008, Devin Heitmueller wrote: > hardware pid filter support. > Does anyone have any experience with hardware pid filters, and have > they provided any signficant/visible benefit over the kernel pid > filter (either from a performance perspective or power consumption)? My opinion: Yes. But then, I've just unearthed a 20-year old `portable' PC, and my `production' machine is somewhat long in the tooth (if you, well, not *you*, but someone in my area, throws away a machine faster than 200MHz Pentium, and with more than 5 PCI-or-greater slots, I'll happily upgrade) My software-filtering cards also speak USB, and on my slow machine, the added load both from sending a complete transport stream over USB, then filtering it, takes a noticeable amount of CPU. I can come close to maxing it out with a DVB-T full stream, an internal PCI HD-H.264 stream, and two additional USB multi-radio streams. And at times I've experienced packet loss. Interestingly, on a faster notebook, a full-TS satellite tuner card via USB does not always give error-free results, for reasons I've not deduced -- but could be related to its use as an end-user machine, while my slow workhorse pretty much exists as a server. Oh, that server has only got 32MB RAM too. Too cheap to upgrade. I am. Yeah. > It's probably a good thing to implement in general for completeness, I have a device which according to what I've read, requires a simple register flip to enable internal PID filtering, or not. As it's valuable to me, I'm willing to see if I can add part of the code needed to enable hardware filtering too. Not that I can code, but I'm willing. To see. If. Also, the streams of interest to me do not necessarily fit into USB1 bandwidth -- I'm thinking an 8MHz 256QAM carrier with five or six high-quality SD MPEG-2 videos of dynamic bandwidth, which exceed my USB1 device capabilities. > but if there isn't any power or performance savings then I'm not sure > it's worth my time. Power savings -- some, as the CPU itself doesn't have to be bogged down tossing bits. Performance savings, for me, significant. Also, for me, can mean the difference between a flawless data stream, and a garbled packet-loss mess. Also, I experience ``oddness'' in data transfer over USB when I'm trying to do several things at once, so in case of weaknesses of the Linux USB stack, it's good to allow the end-user to avoid stressing it until it's as reliable as, well, um, I dunno, floppy support or something, my opinion... > Opinions welcome, Sorted. please ignore. after all, i should've left my current server machine in the pile of e-waste from which I recovered it... thanks! barry bouwsma opinion! i mean, mine! opinion! ignore! mine! drink! girls! fe _______________________________________________ linux-dvb mailing list linux-dvb@xxxxxxxxxxx http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
