GSoC 2012 Linux-Media!

The hacks with USB stick are entirely reliant on the chips inside the stick. In this case, the demod (Realtek RTL2832U)has the ability to pass through to the USB bus raw 8-bit sampled RF called I/Q
(http://zone.ni.com/devzone/cda/tut/p/id/4805).

Once you have this raw I/Q data you can demodulate the signals and process them in software. So it's possible to build an FM radio, an AM radio, a DAB radio, Ham radio, Packet radio, slow scan TV, basically anything which modulates a sine wave within the frequency range of the tuner inside the DVB stick. Not all DVB tuners are created equal. Some will be limited to n hundred MHz, some have a range as low as 50 or 60 MHz up to a few GHz.

Chips that have this functionality AND are built in to DVB USB sticks AND cost less than 20 Dollars are few and far between. So it's pretty rare to find a compatible USB stick, and not every USB stick can pull off this neat trick.

There is probably scope to run a project around a single targeted DVB USB stick, but hardware support would be limited. GNU Radio is a good tool to build the remodulators. As an example real world application, how about building one of these sticks in to a laptop and integrating it with the audio stack. Now my laptop comes with a TV tuner, an FM tuner, a DAB tuner, and so on.

I hope that helps set the scene a little bit more. Let me know if you need any
more help.

Cheers, Will

Hi Till!

I am familiar with what a USB-DVB stick is, how it works, the inside of a DVB transport stream, and so on, but... I'm in no way an expert, and I'm in no way a developer!

Depending on what sort of mentoring you had in mind, I would be happy to get involved.

Can you let me know a little more about the project and what kind of input you need from me.

Cheers, Will

Moikka!

As I have mentioned many people already, I have got Google Summer of Code project for the Linux-Media! It means I can do three months full time work starting from the week 21 (21.05.2012). Originally I applied "Open firmware for ath9k_htc" -project as that was listed but I added own topic for Linux-Media related stuff and it was accepted.

It is rather much time I can spend and fix all those problems I have seen during recent years. Schedule is first to fix all DVB USB problems and then move to enhancing DVB CORE / frontend. I planned only general digital television stuff since it is what I know best. But if there is some time I can likely do some other general fixes.

Here is short description.
http://www.google-melange.com/gsoc/project/google/gsoc2012/crope/10001

I will open another thread just discussing what are the most important things and how those should be fixed "correctly".

And there is no blog yet, but sometime ago I created LinuxTV page for Google+. Lets use it:
https://plus.google.com/u/0/111350562770777789175/posts

And my mentor is Hin-Tak Leung.

regards
Antti

Hi Antti,

I promised to put you in touch with some more knowledgeable people, so here they are. Will made a few comments during our discussions (inserted verbatim below - may or may not be relevant)... Please feel free to respond to Mr Cooke and/or write to him and Greg.

Hin-Tak

Quoted 1 line · Will Cooke

The hacks with USB stick are entirely reliant on the chips inside the

stick. In

Quoted 1 line

this case, the demod (Realtek RTL2832U)has the ability to pass

through to the

Quoted 4 lines

USB bus raw 8-bit sampled RF called I/Q
(http://zone.ni.com/devzone/cda/tut/p/id/4805).

Once you have this raw I/Q data you can demodulate the signals and

process them

Quoted 1 line

in software. So it's possible to build an FM radio, an AM radio, a

DAB radio,

Quoted 1 line

Ham radio, Packet radio, slow scan TV, basically anything which

modulates a sine

Quoted 1 line

wave within the frequency range of the tuner inside the DVB stick.

Not all DVB

Quoted 1 line

tuners are created equal. Some will be limited to n hundred MHz, some

have a

Quoted 3 lines

range as low as 50 or 60 MHz up to a few GHz.

Chips that have this functionality AND are built in to DVB USB sticks

AND cost

Quoted 1 line

less than 20 Dollars are few and far between. So it's pretty rare to

find a

Quoted 1 line

compatible USB stick, and not every USB stick can pull off this neat

trick.

Quoted 2 lines

There is probably scope to run a project around a single targeted DVB

USB stick,

Quoted 1 line

but hardware support would be limited. GNU Radio is a good tool to

build the

Quoted 1 line

remodulators. As an example real world application, how about

building one of

Quoted 1 line

these sticks in to a laptop and integrating it with the audio stack.

Now my

Quoted 3 lines

laptop comes with a TV tuner, an FM tuner, a DAB tuner, and so on.

I hope that helps set the scene a little bit more. Let me know if you

need any

Quoted 3 lines

more help.

Cheers, Will

Quoted 3 lines · Will Cooke

Hi Till!

I am familiar with what a USB-DVB stick is, how it works, the inside

of a DVB

Quoted 1 line

transport stream, and so on, but... I'm in no way an expert, and I'm

in no way a

Quoted 3 lines

developer!

Depending on what sort of mentoring you had in mind, I would be happy

to get

Quoted 3 lines

involved.

Can you let me know a little more about the project and what kind of

input you

Quoted 3 lines

need from me.

Cheers, Will