[linux-dvb] Re: dec2000-t success

[Holger Waechtler <holger@convergence.de>]

Bruce Janson wrote:
>     From linux-dvb-bounce@linuxtv.org Mon Apr 28 12:46:46 2003
>     ...
>     Date: Mon, 28 Apr 2003 12:43:13 +1000
>     From: Douglas Kosovic <douglask@dstc.edu.au>
>     ...
>     Edward Wildgoose wrote:
>     
>     >>the DEC 2000-t's USB 1.1 interface will impose a 12 Mbits/s limit on
>     >>its USB->PC interface.  I do not know the maximum (compressed)
>     >>throughput that can be required by a 7 MHz, DVB-T transport stream
>     >>(23 Mbits/s?), but I suspect that it does exceed 12 Mbits/s.
>     >>If true, this would impose an unfortunate limitation on the DEC 2000-t.
>     >>(USB 2.x at 480 Mbits/s would have avoided this...)
>     ...
>     >I am under the impression that because Australia is using QAM64 (which I
>     >think means more channels per transport stream) you should find that the
>     >channels have a lower max transmission than 23Mbits/s.  In the UK I think
>     >the QAM64 channels are 6Mbit/s.
>     ...
>     I don't know about the calculations based on QAM64, but the Australian
>     HDTV 1080i broadcasts are approx 4 times the resolution of SDTV 576i,
>     so I would expect something like 4 times the bandwidth would be required.
>      From memory, I think it's 19 Mbit/s, but I could be wrong.
>     
>     I wonder if the Australian DVB-T 720P HDTV broadcasts exceed the 12 Mbits/s
>     USB 1.1 limit? I would imagine the bandwidth for 576p broadcasts wouldn't
>     be a problem, but it would be interesting to see if the built in decoder
>     can handle 576p.
>     
>     At least the Australian SDTV 576i channels which are 6 Mbit/s, should work.
>     ...
>
> Thanks.  Good points, but those of us who would like to grab a
> whole transport stream (and then unpack it later if required)
> are going to be disappointed by the Hauppauge DEC 2000-t.
For these purposes you need a higher-bandwidth bus solution, e.g. a PCI 
card or a USB2.0 device. Does anybody of you knows if there is a 
Firewire DVB solution available (or announced?) somewhere?

Holger



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