[mythtv] [mythtv-commits] Ticket #1356: DTVRecorder::FindKeyframes in 0.19 causes video gltiches in firewire recordings

Steven Adeff adeffs.mythtv at gmail.com
Thu Feb 23 19:40:39 UTC 2006

On 2/23/06, Daniel Kristjansson <danielk at cuymedia.net> wrote:
> On Thu, 2006-02-23 at 11:29 -0800, Jim Westfall wrote:
> > Steven Adeff <adeffs.mythtv at gmail.com> wrote [02.22.06]:
> > when looking at both sets of code there is one thing that stands out as
> > not being right.  The use of tspacket->data() as if its going to return a
> > pointer to the start of the entire 188 byte tspacket.  Its like this in
> > both versions of FindKeyFrames, plus a number of locations.
> >
> > The TSPacket class doesnt define a data() function so its getting picked
> > up by TSHeader::data(), which returns a pointer to _tsdata[4].  Accesses
> > past the 4th byte are overflowing and seems to just be a fluke its working
> > since _tsdata[4] and tspayload[184] appear to be next to each other in
> > the stack.
> It's no fluke that they are next to each other on the stack,
> it's very intentional. This allows you to create a TSPacket
> by casting a position within the raw buffer and avoid a memory
> allocation and memory copy.
> -- Daniel

sadly, I have no idea what you guys are talking about, but I sure hope
it will lead to fixing the glitches in the new method that aren't
present in the old method =)

thanks guys!


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