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Reply-To: "Nasser Abbasi" <nma@12000.org>
From: "Nasser Abbasi" <nma@12000.org>
Newsgroups: comp.soft-sys.matlab
References: <gi2bgg$c4c$1@fred.mathworks.com> <fu21l.14039$Ws1.5531@nlpi064.nbdc.sbc.com> <gi2dpg$s87$1@fred.mathworks.com>
Subject: Re: Lossy video transmission
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Date: Sun, 14 Dec 2008 00:06:32 -0800
Xref: news.mathworks.com comp.soft-sys.matlab:506831



<please do not top post>

>
> news:gi2bgg$c4c$1@fred.mathworks.com...
>> >I am trying to simulate a video transmission over lossy wireless channel 
>> >in
>> >Simulink. My project is at the initial stage so there need not be actual
>> >transmission. I just need to introduce errors so that the video played 
>> >at
>> >the receiver is choppy, jittered, loss of data. how do i do that?
>> > I have so far used the video and image processing blockset in MATLAB
>> > r2008a to insert a video source and viewer. I need to add errors in
>> > between these.
>> >
>> > please help me
>>
>> I do not know what the "lossy" part has to do with this. If you want to 
>> just
>> simulate noise in the message itself, then add AWGN noise to the message
>> before the receiver end. This is the most basic way to add noise to a
>> message which account to noise in the transmission channel and to thermal
>> noise at the receiver side as well
>>
>> --Nasser


>> "Sohaib Mansoor" <contact.sohaib@gmail.com> wrote in message
> what I mean is that the video at the receiver's end should be 
> discontinuous,  with some frames missing as well.
> I want it to be simple at this stage, so something in between the source 
> and the viewer, which could randomly drop frames with a certain 
> probability should be sufficient. Any ideas?
>
> thanks in advance

Ok. So what you want is 'custom' made noise.

Then may be just add a block before the receiver end, where it accepts the 
message on one end it does whatever it wants, and generates the result. This 
block/function could drop a frame, delay transmission, or do whatever you 
think needed to simulate the type of noise you want.

Decide of probability distribution to use (flip a coin, or whatever), and 
based on this, do the damage you want to the message, when done, hand it 
over to the receiver end.

--Nasser