[mythtv-users] recommend PCI DVB-T Tuner Card?

Devin Heitmueller dheitmueller at kernellabs.com
Thu May 6 17:48:02 UTC 2010

On Thu, May 6, 2010 at 12:46 PM, Ed W <lists at wildgooses.com> wrote:
> Also, although Devin can probably confirm (?) I thought I saw that several
> USB devices dump the whole TS stream over the USB bus and leave it for the
> host to demux it?
> Devin can you comment on the Peak above? It identifies itself in dmesg as:
>     af9013: found a 'Afatech AF9013 DVB-T' in warm state.
>     af9013: firmware version:4.95.0
>     usbcore: registered new interface driver dvb_usb_af9015

Antti (the af9013 maintainer) can probably confirm, but I believe the
af9015 does not have any onboard hardware PID filtering.  Hence, it
will send the whole MPEG stream across the wire and it is the kernel's
responsibility to do PID filtering.  That said, most of the LinuxTV
drivers do not support hardware PID filtering, even in cases where the
hardware supports it.  This is usually a combination of the register
documentation not being available and, frankly, that it's just not
worth the effort for 99% of cases.  Very few people would see any
tangible benefit to hardware PID filtering (the only environments
where it matters tend to be embedded targets and cases where
significant optimization of the USB bus utilization is required).  The
time on the part of the developer that would need to be spent is just
better spent working on things that users can actually see.


Devin J. Heitmueller - Kernel Labs

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