[vdr] Re: [PATCH] time warp

Marcel Wiesweg marcel.wiesweg at gmx.de
Wed Jun 22 19:09:32 CEST 2005


Am Mittwoch 22 Juni 2005 00:10 schrieb Rainer Zocholl:
> udo_richter at gmx.de(Udo Richter)  19.06.05 16:40
>
> >Klaus Schmidinger wrote:
> >> Isn't all that data protected by CRC32 checksums?
> >> How could "garbage" get in there?
> >>
> >> Maybe somebody should try to find out why that "garbage"
> >> is produced in the first place...
> >
> >I've seen this - though at least one year ago - with bad reception due
> >to bad weather. For half an hour, the system time was jumping back and
> >forward like crazy, starting and stopping some timers. Luckily, all
> >timers were repeating, so none of them was gone after reception was
> >back.
>
> So: Who is doing the CRC checks?
> Maybe it's turned off or only an error bit is set but nobody
> cares about in further processing? (Maybe the cause for
> "unkown picture type" too?)
>
> It's very unlikely that garbage can so often pass a CRC32 check.

The TDT is not specified to contain a CRC32 checksum.
All larger tables have this, NIT, EIT, SDT, also TOT.
The "small" ones TDT and RST have no checksum.

Marcel

>
>
>
> Rainer
>
>
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