[vdr] eHD, VDR and multimedia files

Georg Acher acher at in.tum.de
Thu Jul 24 15:29:58 CEST 2008


On Thu, Jul 24, 2008 at 05:30:46PM +0400, Goga777 wrote:
> > > may be you know - does Pentium 4 3 GHz will be enough ? 
> > 
> > Even 300MHz are enough. The CPU load is not a load that depends on CPU
> > speed. It depends mainly on the current state of the driver which transfers
> > the video data from the CPU over PCI without using bursts. Autonomous DMA
> > should be possible, but is not yet finished.
> 
> do you mean the transfer of compressed (h264 or mpeg2) video data from dvb
> card to eHD ?

Yes, only the TS (or ES) is transfered. Since the Decypher aborts PCI bursts
(I'm not sure if it is just a config setting to circumvent some PCI erratas
in the first chip version or really a HW block to "fix" them...), you end up
with about 12-15MByte/s transfer rate at most. So a typical 20Mbit/s stream
produces about 16% "load" almost independent on the CPU speed.

There are DMA blocks in the chip, but the documentation is a bit ...er...
weak....

-- 
         Georg Acher, acher at in.tum.de
         http://www.lrr.in.tum.de/~acher
         "Oh no, not again !" The bowl of petunias



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