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wireless streaming video question

KorKor Known to detonate from time to timeRegistered User regular
Hey, so anyone that has seen me mention it, I'm involved in a UAV (unmanned air vehicle) rapid prototyping group, and I was hoping one of you guys could help me out with a quick question.

We're at the point that we're testing streaming video from the plane to the ground station. The camera records in 640x480. So about how much data p/s would I need to be reaching in order to see a viable streaming video.

I ask because I need to see if we need to look at other options for the "router" variant we are using.

DS Code: 3050-7671-2707
Pokemon Safari - Sneasel, Pawniard, ????
Kor on

Posts

  • RookRook Registered User regular
    edited June 2008
    It depends if it's compressed or not and what framerate you're looking at. Raw YUV 640x480 30 fps capture is 18 MBps

    Rook on
  • KorKor Known to detonate from time to time Registered User regular
    edited June 2008
    yes, its compressed, and encrypted.

    Kor on
    DS Code: 3050-7671-2707
    Pokemon Safari - Sneasel, Pawniard, ????
  • GrimReaperGrimReaper Registered User regular
    edited June 2008
    Kor wrote: »
    yes, its compressed, and encrypted.

    In that case you need to determine the bitrate you're giving to the compressed video.

    Also, compressing video plus encrypting it may eat into the electricity budget of the vehicle. Depends on how it's powered and how big it is I guess.

    Also, by compressed do you mean lossy or lossless and what kind of compression codec. Is it something relatively simple or something fancier like mpeg 1/2/4. (or even h264)

    GrimReaper on
    PSN | Steam
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    I've got a spare copy of Portal, if anyone wants it message me.
  • KorKor Known to detonate from time to time Registered User regular
    edited June 2008
    mpeg 4, and its powered by an alternator on the engine (and a backup battery) thats feeding it 12V.

    Kor on
    DS Code: 3050-7671-2707
    Pokemon Safari - Sneasel, Pawniard, ????
  • GrimReaperGrimReaper Registered User regular
    edited June 2008
    Kor wrote: »
    mpeg 4, and its powered by an alternator on the engine (and a backup battery) thats feeding it 12V.

    So I assume this is a hardware mpeg4 encoder chip?

    What is your quality preference? Is it just for basic flight control or something where you're needing a decently high quality picture?

    It'll be encoding at a constant bitrate so you should aim for around 50KB/sec, that should give you an okayish picture at 25fps, you'll get blocking but if it's just for basic flight control then you should be okay. Higher data rates will probably mean a decrease in range. Do you know the data encoding used for the radio transmission? If you can get that sucker transmitting on multiple frequencies using something like space–time block coding then you should be sailing. Radio stuff though isn't my speciality.

    When I get time at the weekend i'll do some quick encoding comparison at different bitrates.

    However, if you can get it usable above 50KB/sec then go for it. At that kind of res i'd normally go for anything above 100KB/sec, but I doubt you're looking for pristine image quality.

    EDIT: Also, this is a project i've been thinking about for ages. Building a remote controlled plane and sticking a camera in that sucker for control. But, I don't have a limitless well of money alas.

    GrimReaper on
    PSN | Steam
    ---
    I've got a spare copy of Portal, if anyone wants it message me.
  • KorKor Known to detonate from time to time Registered User regular
    edited June 2008
    Well, I can share that the encoder is a Bosch VIP x2. Most of this stuff was just handed down to me from the last team, that didn't document shit.

    The image needs to have a pretty good quality, as the auto-pilot has an onpoint targetting system. In other words, if you clicked on a car driving down the highway, the plane would do whatever it needed to make sure that car was within view.

    The camera has a 26x optical zoom/12x digital zoom. We need a quality image because one of our customers (the local police force) are wanting to be able to read a license plate with this thing.

    Kor on
    DS Code: 3050-7671-2707
    Pokemon Safari - Sneasel, Pawniard, ????
  • GrimReaperGrimReaper Registered User regular
    edited June 2008
    Kor wrote: »
    Well, I can share that the encoder is a Bosch VIP x2. Most of this stuff was just handed down to me from the last team, that didn't document shit.

    The image needs to have a pretty good quality, as the auto-pilot has an onpoint targetting system. In other words, if you clicked on a car driving down the highway, the plane would do whatever it needed to make sure that car was within view.

    The camera has a 26x optical zoom/12x digital zoom. We need a quality image because one of our customers (the local police force) are wanting to be able to read a license plate with this thing.

    Ah, I thought this was just a fun project someone was doing.

    So, some kind of targetting system like this? By the way, check out the videos there.. some pretty cool stuff.
    Ok, quality.. then you'll need to be going above 100KB/sec. 200KB/sec should give good quality.
    If you've got the chip and some software you could do simple tests anyway.

    Ah, just looked up what you're using. It's a bit of a weird way to approach things, I take it a lot of the stuff isn't custom but more off the shelf things?

    GrimReaper on
    PSN | Steam
    ---
    I've got a spare copy of Portal, if anyone wants it message me.
  • KorKor Known to detonate from time to time Registered User regular
    edited June 2008
    Yeah, its a rapid prototyping team with a small budget of around 30,000 dollars. Though, it definitely is a fun project. :D

    But we're got a team of 4 people working on this, a mechanic, a double-e, a comp programmer (me), and a managerial chick who writes our test plans and safety plans and such.

    This is our auto-pilot. http://www.procerusuav.com/

    Thankfully, none of this stuff is classified or anything, since you can just look it up on wikipedia anyway.

    Kor on
    DS Code: 3050-7671-2707
    Pokemon Safari - Sneasel, Pawniard, ????
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