On Fri, 2008-10-31 at 15:46 -0400, Jeff Campbell wrote: > Hi Andy, > > My apologies for not getting back with the pci details, I've been away > from the hardware that has the problem for a few weeks (and using my > other box). I'm now getting back at it. > > I wanted to followup on your suggestion that I use mplayer with a 16MB > buffer to play the stream if reading directly off /dev/video0. > > While that works, I was curious if there are any plans, or if it is > even possible, to do some buffering on the driver side so that the > resulting native TS is more stable.
First what do you mean by native TS? Analog captures default to an MPEG PS, but supposedly the chip can also be set to do a TS for analog capture (I haven't tested it yet). Digital captures are just a pass-through of the TS from another chip. Well, I have some plans for buffers changes, but buffering up 8 or 16 MB in kernel space wasn't one of them. The problem is one of non-uniform rate of delivery of audio and video buffers, I think. I don't know how to get the chip to transfer 1 video buffer per frame, so the solution is to use smaller transfer buffers to get the chip to hand them over sooner. The problem is the driver is simply written to stay with in the buffer count limit of 63 buffers usable by the firmware at any one time. Making the buffers smaller to smooth out transfers while staying under 63 buffers makes for a very small overall buffer. I plan to change the driver to manage more than 63 buffers per stream and let the user control buffer sizes to meet their latency needs. But right now I investigating some interrupt and mailbox problems to try to resolve problems with simultaneous analog and digital capture. Hopefully that will make things better too. > VLC really chokes on it if you try and play it directly, due to late > picture and late sound. OK. I never tested VLC. I've been away for the better part of two weeks, so I'm catching up on things (home, family, and linux hobby) as I can. Regards, Andy > Thanks, > > -Jeff _______________________________________________ ivtv-devel mailing list [email protected] http://ivtvdriver.org/mailman/listinfo/ivtv-devel
