Re: [Discuss-gnuradio] NTSC Demo

[Prateek Dayal]

Yes .. your code was the starting point for me .... 

Please download the thesis from 

www.geocities.com/pmd_iitgw

It will explain all the stuff ... 

The audio decoding can be done using gnuradio .... I think the best
bet would be to put together a separate decode_ntsc block that can do
the sync extraction and display etc ... the final frame drawing can be
separate ....

I just have to organize the code and I will then put it up on the web
... the video that I sent you was also put together using matlab and a
software for putting the frames together ....
The thesis contains the preliminary color results 

Regards

Prateek 



On 6/13/05, Martin Dvh <address@hidden> wrote:
> Prateek Dayal wrote:
> > Currently I feel that the best place to start off would be to code the
> > monochrome algorithms  in gnuradio frame work .. we need to write the
> > python module for the monochrome decoding .... I will send you my
> > thesis and code soon and then we can write the code .. the problem is
> > that I am not very comfortable in C or python :-(  ....
> I would like to be involved too.
> A while ago I wrote a very simple tv decoder for gnuradio (monochrome only, 
> no synchronisation)
> 
> Is there somewhere where I can download the thesis and any other info.
> 
> All cpu intensive tasks should go into new cpp gnuradio blocks.
> There are already quite some generic blocks so maybe we don't have to write 
> much new ones.
> I think we would need:
> saw_filter (use fir_filter)
> synchronous_am_decoder (new)
> color_comb_filter (use iir_filter)
> audio_filter (use_fir_filter)
> y_(comb)_filter (use iir_filter)
> color_demodulator (new)
> tv_audio_demodulator (use am_detector (abs)for ntsc or fm_demodulator 
> (quadrature_demodulator) for pal)
> synchronisation_block (new)
> streaming_display (new, use SDL)
> audio_output (use audio_sink)
> 
> Then in python we can add all these blocks together:
> 
> fg.connect(usrp_source,saw_filter,synchronous_am_decoder,synchronisation_block)
> fg.connect(synchronous_am_decoder,color_comb_filter)
> fg.connect(synchronous_am_decoder,y_comb_filter)
> fg.connect(color_comb_filter,(color_demodulator,0))
> fg.connect(y_comb_filter,(color_demodulator,1))
> fg.connect(synchronisation_block,(color_demodulator,2))
> 
> fg.connect(color_demodulator,streaming_display)
> fg.connect(synchronous_am_decoder,audio_filter,tv_audio_demodulator,audio_sink)
> 
> 
> We could also put everything into one block. I think we then should start 
> with a  generic monochrome videodecoding block
> gr_videodecoder_analog
> 
> Then write sublasses for ntsc, pal, secam
> 
> There is already code for fm and am audio decoding, Probably we can use this 
> for the audio part.
> Otherwise we could also write tv_audio decoding blocks
> 
> We also wan't to show the decoded video.
> So we could make a
> gr_streaming_bitmap_display
> 
> 
> I think this would be best implemented in a cpp block using SDL 
> (cross-platform)
> This shouldn't be too hard.
> 
> greetings,
> Martin
> >
> > i will send you the files soon
> >
> > regards
> >
> > Prateek
> >
> > On 6/9/05, Matt Chapman <address@hidden> wrote:
> >
> >>I'd like to volunteer, I've been trying to decode NTSC to build a vector
> >>scope. This seems like the perfect project to get me going in the
> >>correct direction.
> >>
> >>Is there something in particular you need help with?
> >>
> >>
> >>
> >>
> >>
> >>
> >>On Thu, 2005-06-09 at 20:32 -0700, Prateek Dayal wrote:
> >>
> >>>Hi,
> >>>
> >>>Take a look at
> >>>
> >>>www.geocities.com/pmd_iitgw/ntsc_final.zip
> >>>
> >>>This video was extracted from data sampled by the USRP ....
> >>>
> >>>The code is currently in matlab and I am in the process of porting it
> >>>to gnuradio but lack the required python and C experience ...
> >>>
> >>>I have written a long thesis on the elements involved and basic color
> >>>decoding is also working ...  I have attached a jpg file ..  note the
> >>>brown color of the wooden stuff hidden below the green tint :)
> >>>
> >>>things remaining -->
> >>>
> >>>1. carrier tracking ... for better comb filter performance
> >>>2. gnuradio code
> >>>
> >>>I would really appreciate if someone with python experience or
> >>>gnuradio experience would like to share his time towards the work ...
> >>>
> >>>Regards
> >>>
> >>>Prateek
> >>>_______________________________________________
> >>>Discuss-gnuradio mailing list
> >>>address@hidden
> >>>http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> >>
> >>--
> >>Matt Chapman <address@hidden>
> >>
> >>
> >
> >
> 
> 
> 
> 
> _______________________________________________
> Discuss-gnuradio mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/discuss-gnuradio
> 


-- 
Prateek Dayal
B.Tech 4th Year
ECE
IIT Guwahati

www.geocities.com/pmd_iitgw