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  1. Hi.

    I hope you guys can help me. I am using an ultrasound device and I would like to grab the video from this over to my computer, but the format that is captured is wrong. The setup is like this: The ultrasound machine sends S-Video to a Sony HDV GV-HD700 which sends via firewire to a computer that uses a specialized video grabber program.

    The HD device has the following ports: S-Video and Video in - HDV/DV, HDMI, Component, A/V out

    And the computer has to use firewire.

    The ultrasound machine produces 800x600 format and that is what I would like to get out. Any ideas on how I should set this up? When I tried Ultrasound -> S-Video cable -> Hd device -> HDV/DV to firewire -> Computer, it produced 768x576. If anyone has any ideas, it would be nice. I'd hate to have to go and buy all different cables to try

    Thanks.
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  2. aBigMeanie aedipuss's Avatar
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    set the HDV cam to DVavi mode including DVavi out from the firewire port. capture over firewire to DVavi 720x480 if you are ntsc or 720x576 for pal. it's 4:3 with odd shaped pixels that convert to 640x480 or 768x576 square pixel format.
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  3. Thanks for your quick reply!

    I will have to check in the morning if I've got 720x576 or 768x576. Two questions:

    How can I check if my files hace odd shaped or square pixels? How does the conversion from odd shaped pixels to square pixels happen (what software would I need, if any)?
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  4. aBigMeanie aedipuss's Avatar
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    DVavi only comes with non-square pixels, it depends on the software you use to convert it. some know to change the size to a square pixel 4:3 like 640x480, 800x600, 768x576, but some require you to set it to a proper size.

    use mediainfo on the files to get a good idea of what the properties of the video are. put mediainfo into text mode then open your file with it.
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    "a lot of people are better dead" - prisoner KSC2-303
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  5. Thanks again! Turns out that the videos captured through firewire are indeed 720x576. From your information, I would think that those are "odd sized pixels". Below is what MediaInfo says. It claims that the aspect ratio is 5:4, which to my limited understanding means that the pixels are interpreted as square...

    I have measured the aspect ratio of the ultrasound image (i.e. excluding some text areas that are also part of the video image), using ImageJ and the ultrasound analysis software. The ratio of the original files (produced on the ultrasound machine) and the files sampled through firewire is not the same. What I'm looking for is to maintain this ratio when I sample the video files on the computer.

    Is there something wrong with the way the file is saved through firewire (incorrect interpretation of the type of pixels?), or do I just need a tool to convert my video? I have got Super, but I can't find any settings related to pixel type.

    Format : AVI
    Format/Info : Audio Video Interleave
    File size : 88.7 MiB
    Duration : 18s 320ms
    Overall bit rate : 40.6 Mbps
    Video
    ID : 0
    Format : JPEG
    Codec ID : MJPG
    Duration : 18s 320ms
    Bit rate : 40.5 Mbps
    Width : 720 pixels
    Height : 576 pixels
    Display aspect ratio : 5:4
    Frame rate : 25.000 fps
    Standard : PAL
    Color space : YUV
    Chroma subsampling : 4:2:2
    Bit depth : 8 bits
    Scan type : Interlaced
    Scan order : Top Field First
    Compression mode : Lossy
    Bits/(Pixel*Frame) : 3.909
    Stream size : 88.5 MiB (100%)
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