[linux-dvb] Question about Philips SAA7146A multimedia bridge

[Valery Febvre <vfebvre@easter-eggs.com>]

In the application note DPC7146-23 of the Philips SAA7146A Multimedia
bridge, I have read this:

Page 14:
With its two D1 ports it can provide simultaneous video-capture and
video-play-back capability.

Page 28:
It makes clear that beside the video capture also the video play-back is
possible on the same structure.
...
The drawn case, the video input (video capture) and the video output
(Video Play-Back) operate independently. The video engines of the
SAA7146A provide a strong capability to enable both features
simultaneously, never-theless the need a certain support from the rest
of the system. Early PCI-chip sets and early PCI VGA boards might not
follow completely to PCI requirements. This can have some impact on the
combined video performance.

To test this, I have used 3 different applications:
- a dvdplayer (http://www2.arnes.si/~mthale1/dvb_french.html)
  It uses the last Driver DVB-s driver version 0.9
  It uses device /dev/ost/video, /dev/ost/audio, /dev/ost/osd
  Philips PCI bridge and Texas Intrument mpeg decoder
- the player "tuxplayer" provide with DVB-s driver version 0.9
  It uses device /dev/ost/video, /dev/ost/audio, /dev/ost/osd
  Philips PCI bridge and Texas Intrument mpeg decoder
- a little channel recorder (a software written by myself)
  It uses device /dev/ost/demux (video), /dev/ost/demux (audio),
/dev/ost/dvr
  Demux and Philips PCI bridge

If the PCI bridge is really full-duplex, I can use simultaneous:
- dvdplayer + recorder
or
- tuxplayer + recorder

Here are the results:
1) first the dvdplayer and after the recorder
   When I launch the recoder, the dvdplayer is stopped, and the recorder
doesn't work.
2) first the recorder and after the dvdplayer
   When I launch the dvdplayer, the video screen is black (nothing), but
the recorder works.
3) first tuxplayer and after the recorder
   idem 1)
4) first the recorder and after the dvdplayer
   idem 2)

For me, it doesn't work. I can only tell that the video-capture has
priority on the video-play-back if it's used first.

Can you help me about this hardware feature?
Is it a hardware problem or a Linux DVB-s driver problem?

Thx in advance.
Best regards.

--
Valéry Febvre / Easter-Eggs              Spécialiste GNU/Linux
44-46 rue de l'Ouest  -  75014 Paris  -  France -  Métro Gaité
Phone: +33 (0) 1 43 35 00 37    -   Fax: +33 (0) 1 43 35 00 76
mailto:vfebvre@easter-eggs.com  -   http://www.easter-eggs.com

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