[linux-dvb] Re: video + net with Nexus

["Augusto Cardoso" <augusto@carhil.net>]

Hi!

OK. Thanks for the explanation.

	Augusto

*********** REPLY SEPARATOR  ***********

On 12/21/2003 at 10:41 PM Ralph Metzler wrote:

>Augusto Cardoso writes:
> > I may have miss the point here, however, I have run the skystar2 cards
>at 38Mbps IP payload speeds without dropping any packets for more than 24
>hours. With the FCII/FCIIB the maximum speed that I got is about 41Mbps.
>With FCIII I have tested it at 78Mbps and simulated it at 120Mbps. (Note
>this tests were done at B2C2 with B2C2's drivers).
> > When I used to work at B2C2, we focus on data applications. That is the
>main reason the B2C2 Windows driver is a NDIS driver and the B2C2 Linux
>driver is a network driver. Unfortunately, the B2C2 drivers are
>proprietary and very cumbersome.
> > 
> > We did developed a software package for testing data in Unicast and
>Multicast. We also run the data in the same transponder that we run the
>video/audio. We tested receiving all IP data and video/audio without any
>problems.
> > 
> > I haven't done much data tests with the linuxtv.org drivers, mainly
>because my use is for video/audio MPEG2 data.
> > 
> > Can this be a latency issue in the driver? How are you testing? What
>type of applications/protocol? What's the service provider?
>
>
>What I wrote was only related to the "full-featured" Technotrend cards.
>They basicaly consist of a tuner, an SAA7146 as PCI bridge, a TI AV7110
>(demux,
>MPEG2 decoder, ARM core, etc.) with SDRAM and DRAM and 8KB dual ported
>RAM connecting the AV7110 and SAA7110. 
>The transfer from the AV7110 to main memory (via SAA7146) is the
>problem. The ARM core (40 MHz ARM7TDMI) has to buffer and move
>the data (in software) from SDRAM to the dual ported RAM and from there
>it is DMAed by the SAA7146 to main memory.
>Both the buffering and the moving are very slow on the 40 MHz ARM.
>
>The AV7110 also has internal hardware section filters. They tend
>to have dropouts or even filter lockups when the data rate goes beyond
>10Mbit. So, it basically does not matter if we use hardware filters or
>move the whole PID to the PC memory and filter in software.
>
>
>Ralph
>
>
>
>
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