[vdr] future VDR and Net??eiver OEM from Reelmultimedia

Georg Acher acher at in.tum.de
Fri Jun 29 18:24:23 CEST 2007


On Fri, Jun 29, 2007 at 08:21:45AM -0700, Jeremy Jones wrote:
 
> I checked out the latest Reelbox testing svn code and browsed the code to
> see if it supports this device.  I didn't look too thoroughly but it appears
> the reelbox-0.9.0 plugin does support it.  It looks like communication to
> the kernel space driver is done through shared memory and I did see some
> kernel space code to create this shared memory device (/dev/hdshmem).  I'm
> sure there is a closed source firmware or kernel module that is also used
> but since Reelbox is based on vdr this shouldn't be too much of a problem.

Actually there's not much closed source that affects the usage. On the PC
side there's none, on the card side it's only the driver for the HDMI-chip
in the kernel (otherwise Silicon Image would shoot us) and of course the
firmwares for the internal audio/video-coprocessors (delivered by Micronas).

The Linux on the card is a busybox-based MIPS-Linux. In the card itself the
video stuff is done over a modified V4L2. We choose not to expose this API
into the PC, as it would require too much kernel hacking. Instead there's
only the shared memory abstraction with very little kernel code and a
FIFO-channel implementation on top of it. The video player just uses this
comunication and streams raw TS over such a channel. As there is also a IP
network connection over the shm, you can telnet into the card, mount NFS or
stream directly from an application running on the MIPS (with a little
overhead, but it's good enough for >5MB/s).

-- 
         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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