Re: [Discuss-gnuradio] [GSOC17 - Draft proposal] Implement SigMF functionality for GNU Radio

[Bastian Bloessl]

Hi Kostis,

great to see a proposal on SigMF!

I really like the proposal and your experience in the the area is
impressive. When reading through the document, some points were not
completely clear to me.

- You mention that sources and sinks will handle PDUs and Tagged
Streams. I wonder what would be one PDU. A SigMF "capture segment" or
some other chunk of samples. Also are you sure you want to use Tagged
Streams? Maybe you meant normal streams with tags? With Tagged Streams,
you would have to fit the whole capture segment in the input buffer of
the block. That might not be possible.

- You mention that RapidJSON code is messy. Does it auto-generate code?
That could even be an advantage, since SigMF might well go through some
more iterations. Did you plan to also create wrappers for Python?

- The goal of SigMF seems to be to provide a very minimal spec, and I
think many users will have to rely on custom extension in namespaces.
Maybe you could describe a bit how source/sinks and the GUI could deal
with these extensions.

- You will provide the means to filter data. Did you only plan to filter
specific capture segments or also arbitrary samples based on
annotations? Since you mentioned modulation, which is, AFAIK, currently
not specified, did you plan to allow filtering on custom properties?

- Regarding the GUI, it seems as if you plan to develop something from
scratch. Did you consider extending projects like "such samples" from
Tim or Inspectrum?

- I wonder what would be the workflow when creating a SigMF recording.
An issue might be that you cannot immediately write the SigMF meta file
during recording. (For example, the hash has to be calculated after the
recording. Or the annotations have to be written after the capture
segments.). Did you plan to create the meta data in memory and write the
file when the flow graph shuts down (which might cause data loss when
you experience a segfault) or do you write meta data to disk in an
intermediate format that you have to post-process manually to create the
final SigMF files.

Would be great to hear your thoughts on that.

Best,
Bastian



On 03/23/2017 07:37 PM, Kostis Triantafyllakis wrote:
> Hello,
> 
> My name is Kostis Triantafyllakis, graduate student of Computer Science
> at the University of Crete.
> I'm interested in the project of SigMF functionality implementation for
> GNU Radio.
> 
> I have started working on my proposal and I kindly ask for your feedback.
> Please find the draft below:
> 
> https://github.com/ctriant/GSoC17-Proposal/blob/master/README.md
> https://github.com/ctriant/GSoC17-Proposal/blob/master/gsoc17_proposal.pdf
> 
> Thank you in advance,
> 
> Kostis
> 
> 
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