[mythtv] [mythtv-commits] mythtv commit: r10651 by danielk

Janne Grunau janne-mythtv at grunau.be
Fri Jul 28 08:11:23 UTC 2006


On Thursday 27 July 2006 17:32, Daniel Kristjansson wrote:
> > It can, just set filter and mask for all PIDs to 0x00. This is a
> > kind of silly except that it makes the transport stream table
> > monitor obsolete. Updated filters and mask attached.
>
> Right. You could just make the mask and filters 0x0 for every pid,
> but I was afraid doing this could break the very USB DVB devices
> we're trying help.

Most of the devices have probably only a pid filter in hardware an 
filter the section in kernel. So it shouldn't make a difference.

> and it is safe for 
> 0x1ffb since none of these devices are ATSC devices.

Technisat has according to the linuxtv wiki a usb1.1 ATSC device. 
http://www.linuxtv.org/wiki/index.php/DVB_USB#Technisat.2FB2C2_Sky.2FAir.2FCable2PC_USB_.28Flexcop-based.29_.28DVB-S.2FT.2FC_.2F_ATSC.29

> I'm actually a little concerned about the default, since this would be 
> used for the PMT, but if someone complaints we can change it back to
> filter and mask of 0x02 and 0xff, respectively. 

I think it's safe. see above

> > PMTs on these PIDs also fixed but I'm afraid other ATSC can also be
> > on these low PIDs. If this is the case I should stop to change the
> > filter parameters.
>
> In theory ATSC could put other ATSC tables on the NIT and SDT pids,
> but in the wild all I've seen is a PMT on pid 0x10.

Strange, I thought 0x10 is also in the MPEG spec reserved for a NIT 
which isn't specified.

> > Removing the transport stream table monitor should not happen
> > before 0.20 release. But further improvements to the section reader
> > should be possible if they don't touch anythong other.
>
> As long as they section monitor doesn't give the DVBStreamData data
> which the TS monitor doesn't give it, the changes should be safe.

If they listen on the same PIDs and are both bug free I see no reason 
why the should deliver different data. But the sectionreader isn't bug 
free. I get sometimes only partial reads and bad packets and their CRC 
is never checked.

> I'm  out of town all of next week so I won't be around to apply 
> emergency fix patches in that time...

I hope they are not neccessary.

> I'm all for using the section monitor in the DVBSignalMonitor, it's
> just too late for 0.20.

Good, I will look into resurrecting parts from dvbsiparser.

Janne


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