Re: Format of /dev/video or where to get MPEG TS stream?

[Terry Hardie <terryh@orcas.net>]

    [ The following text is in the "X-UNKNOWN" character set. ]
    [ Your display is set for the "ISO-8859-1" character set.  ]
    [ Some characters may be displayed incorrectly. ]

On Thu, 23 Mar 2000, Ralph Metzler wrote:

> Terry Hardie writes:
>  > The /dev/vbi stuff work mostly, but if I set filters in a loop, two at a
>  > time as you suggest, with at least 1 second pauses between checks, after
>  > 30 or so iterations, the filters won't report any more data, even though I
>  > know there's data there, and it will show up if I start the scan closer to
>  > the PID with know data. I've tried it with calling VIDIOCSSHUTDOWNFILTER
>  > on each pass, and without, and it doesn't seem to change. Any suggestions?
>  > 
>  > Also, during the scan, it's possible for the kernel to start reporting
>  > "outcommand error", and the only way to get rid of it is to remove the
>  > modules and reload them.
> 
> "outcommand error" indicates that the firmware is no longer responding 
> to command requests of the driver. This can e.g. happen when there is 
> too much data coming in for the PID filters.
> There is some overflow recovery code in the firmware but I guess it does
> not always work.
> 
> I donīt understand why you have at least 1 second pause between
> checks. This way you are actually asking for buffer overflows.
> If you always expect data you should use an extra thread which always
> waits for data using poll() or select().
> Keep in mind that the current firmware is not really written to handle
> high data rates >10MBits/s. The memory allocated for buffering on 
> the card is rather small.

I use the flag on the filter that should only give me one packet (I
beleive it the 0x0 flag). I wait 1 second to be sure whether there is data
on that PID or not. Surely with the 1 second pause and the "give me 1
packet only" option, I shouldn't get any buffer overflows?

---
Terry Hardie					terry@gxc.com
Founder and Chief Technology officer		ICQ#: 977679
Convergence Equipment Co, Manassas, VA, USA	V: +1-703-361-5566
"Home of the BOB Class 4 convergence switch"