[mythtv] [mythtv-commits] Ticket #2664: Backend SEGFAULT on invalid PMT

[Daniel Kristjansson]

On Mon, 2006-11-13 at 14:37 +0100, Janne Grunau wrote:
> On Sunday 12 November 2006 23:34, MythTV wrote:
> >  This can only happen with broken hardware for which we have to
> > disable CRC checking,
> This is unfortunately not true. The packet assembler has bugs left. 
> Several people (including me) still see bogus EIT packets though at a 
> much lower rate.
Hmmm, that sucks. But I don't think it is related to this
problem, PAT's and PMT's are usually in one or two TS packets
which I think we handle ok.

> Starting end of october/begin of november Stuart Morgen and I started to 
> see more pes packet assembler warnings ("Started pespaket 
> but !payloadstart",...). Strange thing is that I haven't found a 
> related change set since 0.20 release.
I don't think anything has changed in MythTV, but it's possible
something changed in the transmission or DVB drivers to give us
packets that we don't handle correctly.

> I'm not sure if our handling of DVB SI packets is part of the problem. 
> We handle them currently in the assembler as PES packets which they 
> clearly aren't. They have for example no HAS_CRC flag since they have 
> all crc.
I plan to address this when I fix #799, fixing both will require
me to study the MPEG standards with respect to PES packets to fix
intelligently (i.e. both efficiently and correctly). But for now
couldn't we just make the HasCRC() method virtual and have it
always return true for SI sections?

-- Daniel