Hi Konstantin!
I received your "present" :-) - many thanks! I already ported my base-
band
demux code to the current linux media master branch (in the v4l-dvb
git repo).
It currently allows drivers/frontends to pass base-band frames to the
bb-demux.
The bb-demux allows user-space filtering for BBFrames, TS packets, etc
via
the demux handle or dvr device. It also allows other kernel components
to do
base-band filtering (e.g. receive BBFrames on a specific ISI).
Currently, the bb-demux only accepts a single, complete BBFrame in a
single buffer, but I think
it should also be able to cope with a stream of data (for ease of
driver integration), including
synchronization (search for frame start) and buffering (for assembling
frames).
Besides checking whether the current user-space API for base-band
filtering is useful,
there are a few remaining design questions to think about:
* How to allow pes/section filtering when receiving multiple TSs in
parallel (on different ISIs)
- allow to "stack" filters, e.g. a bb-demux filter delivers TS from a
certain
ISI and forwards it to a section filter (which then passes sections
to user-space).
- dmx / dvr device for each?
* When and how to bring frontend into base-band data mode (a mode
where it delivers
BBFrames instead of TS)?
- Should this be set by the user or happen automatically?
* How to set ISI on demux if we receive TS on a channel with MIS
(if this is not already possible, didn't check it yet)
- this could be covered by the bb-demux filtering API, although the
base-band
demux is not directly involved in this case (since TS data is
delivered to dvb-core).
For now, I'm working to setup a public GIT repository, so you can have
a look at the current status.
Do you have a repository for the TBS drivers or should I use the
official ones? Do you have
an idea of how to program the STV900 to output BBFrames?
Thanks again and kind regards,
Christian.
Am 17.01.2012 um 21:04 schrieb Konstantin Dimitrov:
hi Christian,
it's great that you find it interesting too. i already prepared the
package and i will send it tomorrow - you should get in shorty - i
believe even with the most inexpensive shipping service within Europe
you will get in just a week or so. i hope you will have fun with the
TBS 6925 board - even if not for anything else just to receive DVB-S2
in Linux.
kind regards,
konstantin
On Thu, Jan 12, 2012 at 3:06 PM, Christian Prähauser
<cpraehaus@xxxxxxxxxxxxxx> wrote:
Hi Konstantin!
Thank you, and a happy new year to you too!
The way to proceed you suggested sounds very interesting too me! I'd
be more than happy if you could send me the TBS 6925 card to my
university
address:
Christian Prähauser
c/o Department of Computer Sciences
University of Salzburg
Jakob Haringer Str. 2
A 5020 Salzburg
AUSTRIA
I will start to update my patches to match recent LinuxDVB sources
and
try to integrate Baseband demux support into the TBS linux driver.
If this works, we can also put in GSE-support (S2-native
encapsulation for
carrying IP packets in DVB). This would then probably start to be
interesting
for some people...
Thanks and kind regards,
Christian.
Am 10.01.2012 um 20:40 schrieb Konstantin Dimitrov:
hello Christian,
and Happy New Year to you!
thank you for joining the discussion, but apparently and
unfortunately
Mauro current priorities are not to bring V4L to a next-level, as
you
call it in your article to next-generation. anyway, i think your
work
is very interesting and the least i can do is to offer you, if you
agree and give me your address, to send you as gift one TBS 6925
card
- i had two samples of such card, because i made the Linux drivers
for
it and i can send you one of those two boards to you. what is
interesting about the card that in Windows TBS has tool called "TBS
Recorder" that can capture BBFrames - i'm not sure if the capture is
entirely correct, but at least checking with hex-editor the BBFrames
headers are present in the data dump. also, datasheets of the
demodulator in use on the board confirm that it can output
BBFreames.
so, we can try just for fun to merge your work on BB-demux to V4L
tree
with TBS 6925 support and see if we can get real hardware take use
of
the BB-demux. what you think about such idea?
kind regards,
konstantin
On Tue, Dec 27, 2011 at 12:12 PM, Christian Prähauser
<cpraehaus@xxxxxxxxxxxxxx> wrote:
Yes, I'm meaning something like what it was described there. I
think
that the code written by Christian were never submitted upstream.
Hello Mauro,
Konstantin drew my attention to this discussion. Indeed, some
time ago I
wrote
a base-band demux for LinuxDVB. It was part of a project to
integrate
support
for second-generation IP/DVB encapsulations (GSE). The BB-demux
allows to
register filters for different ISIs and data types (raw, generic
stream,
transport stream).
I realized that the repo hosted at our University is down. If
there is
interest,
I can update my patches to the latest LinuxDVB version and we can
put
them on a
public repo e.g. at linuxdvb.org.
Kind regards,
Christian.
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---
Dipl.-Ing. Christian Praehauser <cpraehaus@xxxxxxxxxxxxxx>
|| //\\//\\ || Multimedia Communications Group,
||// \/ \\|| Department of Computer Sciences, University of
Salzburg
http://www.cosy.sbg.ac.at/~cpraehaus/
http://www.network-research.org/
http://www.uni-salzburg.at/
---
Dipl.-Ing. Christian Praehauser <cpraehaus@xxxxxxxxxxxxxx>
|| //\\//\\ || Multimedia Communications Group,
||// \/ \\|| Department of Computer Sciences, University of Salzburg
http://www.cosy.sbg.ac.at/~cpraehaus/
http://www.network-research.org/
http://www.uni-salzburg.at/
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