[linux-dvb] Re: tech questions 2 - non-mpeg content and fps conversion

[Ralph Metzler <rjkm@convergence.de>]

Arpi writes:
 > > Arpi writes:
 > >  > Is it possible to pass non-mpeg content (PCM audio and YUV 4:2:0/4:2:2
 > >  > video) to the card?
 > > 
 > > Only PCM audio and currently I only support it in PCM PES packets.
 > You mean PCM packets in 0x1BD streams, with additinal 0x0180 PCM header?

Yes.
 

 > > Transmitting uncompressed YUV needs too much bandwidth.
 > Hmm. Is 15MB/sec too much? Some PCI videocards supports YUV and it's
 > very fast...

Well, that's the difference between a video memory connected to
a PCI or AGP bus and one that is somewhere behind a DPRAM.
The data first has to be copied via the DEBI port of the SAA7146 
to the DPRAM. AFAIR the maximum transfer speed is 12MB/s in the 
mode used in the driver. I tried faster ones but this did not work.
This all happens in blocks of max. 8KB. So, add a lot of IRQ handler
overhead. Then the data has to be copied from the DPRAM to the video 
memory by a 40 MHz ARM ... 


 > > No, the card cannot do this. It also cannot create PAL60 signals. 
 > > 
 > > The EM8400 based MPEG2 decoder cards can do this.
 > > 
 > Ok, thanks.
 > I'll do that in software then...
 > 
 > Btw, does the card uses PTS values for something?
 > (except A-V sync if both A and V sterams are present)

No.


Ralph


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