Re: [xine-devel] Satellite input plugin - need advice

[Miguel F. <mi...@ce...>]

Hi Andr=E9,

On Tue, 2002-04-09 at 12:58, Andre' Draszik wrote:
> According to Miguel Freitas:
> > On Sat, 2002-04-06 at 20:44, Steve Brown wrote:
> > >  - Yet another is to not filter in the driver at all, but to send the=
=20
> > > whole transport stream to the demuxer and have the filtering done the=
re.=20
> > > Although this seems pretty clean, I doubt that the performance would =
be=20
> > > acceptable.
> >=20
> > Why not? Wouldn't you need to read the data anyway?
>=20
> Please consider that if you want the driver to send the complete TS to th=
e
> app, you are excluding all the people having a full featured (i.e. with M=
PEG
> decoder onboard) DVB card as those aren't able to handle these high
> datarates.
> And - we are speaking of datarates of ~40Mb/s, so imho it would have a
> noticable performance impact, at least the cpu load would go up for
> nothing...

I may be completely clueless here since i don't know how these DVB cards
work. xine architecture shouldn't care much about "sending" large
datarates since there's usually no memory allocation/copying associated
with that. Assuming that you _have_ to read data from a card in order to
filter it (which i don't know if it's true) means just sending a pointer
of the buffer to demuxer.=20

This is why i don't see this performance impact besides wasting some
buffers. If the card itself has other way of filtering data (so you
don't have to read), of course, i agree with you about the wasted cpu
load/bandwidth...


regards,

Miguel