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  1. Member
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    Hey everyone, I am setting up a home studio to record training videos..

    The goal: Record video and audio directly to the computer.

    The Problem: When recording directly to the computer the video quality is much worse than when I record to a SD card and transfer the video.

    Equipment I have:

    Magewell capture card gen 2 and the USB 3.0 cable I have that came with it

    Sony mirror less camera a6300

    mini HDMI to HDMI (connects the camera to the capture card)

    3 month old Alien Desk top, 32gigs of ram, NVIDIA Geforce GX 1080 display card

    Vmix trial

    In summery: here is a link to a poor quality that is recorded directly to the computer and good quality video is from the SD card. https://drive.google.com/open?id=1qaFR5DYqB5RZnss864X-j-EwJc6LSVnF

    What I cant figure out is why the big difference in quality in recordings. I have tried this same test with OBS and got the same thing. From what I understand the magewell shouldn't be the issue and I know my computer is not the issue.. What I am not familiar with is the more technical side of things such as settings that may be the cause and bit rates or maybe its the wires connecting it all? I dont know but I have spent a ton of time on this and need some help figuring this out so I can move on to the next step and get to creating.
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    I suspect something in the encoding/capture software; there is an obvious frame rate problem -
    not much movement in your video but you can clearly see some jerky sections as frames appear
    to be dropped.
    Have you checked the CPU utilization during capture? Is the software using HW acceleration
    from the graphics card? If so, try turning it off
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  3. Member Cornucopia's Avatar
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    One thing that would explain the framerate drop: if you use the magewell - which has a usb 3.0 interface - with v2.0 port, it drops the available bitrate limit from 5Gbps to 480Mbps. Basically 1/10 of the capacity. Since that family of devices only supports a few kinds of stream, all of them uncompressed, what happens is your available framerate has to drop down to where the total bitrate can fit within that lower limit. This means dropping from 60p to 10 or 7 or 6p. Literally.

    Scott
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  4. Member dellsam34's Avatar
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    Recording uncompressed requires expensive hardware, and if your camcorder doesn't support uncompressed what happens is it compresses the video during shooting for storage on the media while decompressing it and outputting to HDMI, then the Magewell compresses the stream again and sends it over USB, Double loss which usually leads to incompatible framerates.
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  5. The poor quality recording looks to me like it was downscaled to standard definition interlaced video, output as composite vdieo, captured at SD resolution, deinterlaced somewhere along the way, then upscaled to HD resolution.
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    Originally Posted by davexnet View Post
    I suspect something in the encoding/capture software; there is an obvious frame rate problem -
    not much movement in your video but you can clearly see some jerky sections as frames appear
    to be dropped.
    Have you checked the CPU utilization during capture? Is the software using HW acceleration
    from the graphics card? If so, try turning it off
    No, I am a novice when it comes to video so thats how I ended up here.. I can certainly do that check the CPU.. I suspect its not being impacted much but I dont know..

    I dont really know what HW acceleration.. I an tell you that the Magewell does not come with and software and I can check into the vmix.. I also used OBS and the same thing has happened.. same bad quality that is..

    as for the frame rate, this is a separate issue right? I can adjust the frame rate in the camera pretty easy.. I actually dont remember what this was shot on..
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    Originally Posted by Cornucopia View Post
    One thing that would explain the framerate drop: if you use the magewell - which has a usb 3.0 interface - with v2.0 port, it drops the available bitrate limit from 5Gbps to 480Mbps. Basically 1/10 of the capacity. Since that family of devices only supports a few kinds of stream, all of them uncompressed, what happens is your available framerate has to drop down to where the total bitrate can fit within that lower limit. This means dropping from 60p to 10 or 7 or 6p. Literally.

    Scott
    ugh that sounds really bad.. the only thing believe I know is that others are doing this with the device.. I do have another alternative to get a mounted cpu capture card which I am willing to do.. but I shelled out 300 bones for this one I have cause it was supposed to be one of the best.. Gamers use it often to record game screens with perfect clarity and from what I know frame rate..

    again Im pretty green with this kind of stuff though.
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    Originally Posted by dellsam34 View Post
    Recording uncompressed requires expensive hardware, and if your camcorder doesn't support uncompressed what happens is it compresses the video during shooting for storage on the media while decompressing it and outputting to HDMI, then the Magewell compresses the stream again and sends it over USB, Double loss which usually leads to incompatible framerates.
    So the camera I am using is a Sony a6300... mid range camera that is used to shoot a lot of video for people.. but I have never read or heard of it compressing the video..
    I would think not though..

    https://www.bhphotovideo.com/c/used/1222773/?gclid=Cj0KCQjwoInnBRDDARIsANBVyATnLIhS4m_...&lsft=BI%3A514
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    Originally Posted by jagabo View Post
    The poor quality recording looks to me like it was downscaled to standard definition interlaced video, output as composite vdieo, captured at SD resolution, deinterlaced somewhere along the way, then upscaled to HD resolution.
    Okay sounds like you have a lots of experience.. lol.. what I can do is shoot a video of the set up if that will help.. strange thing to me though as far as I know the capture card should be able to handle what I am doing.. here are the specs below for everyone..

    ps loving this forum very helpful bunch!.

    https://www.bhphotovideo.com/c/product/1105735-REG/magewell_xi_100_d_usb_hdmi_one_hd_h...sb.html?sts=pi

    Magewell 32060 Specs
    Host Interface USB 3.0, 300-350MB/s throughput
    USB 2.0 40MB/s throughput
    HDMI Input HDMI 1.4a standard, and support up to 1080p/60Hz 8-bit, (RGB, YUV)
    Output Resolutions Resolutions: 640480 / 720480 / 720576 / 768576 / 800600 / 1024768 / 1280720 / 1280800 / 1280960 / 12801024 / 1368768 / 1440900 / 16001200 / 16801050 / 19201080 / 19201200 / 640360 / 856480 / 960540 / 1024576
    Frame-rate: 25/29.97/30/50/59.94/60 fps
    Sampling Rate HDMI: 165 MHz
    USB Standard Meets the standards of UVC (USB video class) and UAC(USB audio class)
    Color Space YUY2, RGB24
    Hardware adjustable
    Scaling Hardware based
    Image Adjustment Brightness, contrast, hue, saturation
    Operating System Windows 7 (x86 and x64 version)
    Windows Server 2008 R2
    Windows 8
    Windows 8.1
    Linux (Kernel version 2.6.38 and above)
    OS X (10.8 and above)
    Software Compatibility Windows Media Encoder (Windows) Adobe Flash Media Live Encoder(Windows, OS X) Real Producer Plus(Windows)
    VLC (Windows, OS X, Linux)
    QuickTime Broadcaster (OS X)
    QuickTime Player (OS X)
    Wirecast (Windows, OS X)
    APIs DirectShow (Windows), DirectSound (Windows),V4L2 (Linux), ALSA (Linux)
    Onboard Memory 64MB DDR2, 16 bits at 300 MHz
    Upgradeable Firmware Yes
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    *** note I did a test where I unplugged the magewell (micro usb to usb) and hooked up the camera with its (micro HDMI to HDMI) and the same grainy look appeared.. I can create a video of that too..
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  11. Member Cornucopia's Avatar
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    But are you using a USB 2.0 port? Or USB 3.0?

    Btw, fyi I am very familiar with that device as I recommended & support hundreds of them at a University campus. If you set it up properly, it will give you glorious looking (1080p60 or better, depending) video.

    Scott
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  12. Member dellsam34's Avatar
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    Originally Posted by daboat View Post
    Originally Posted by dellsam34 View Post
    Recording uncompressed requires expensive hardware, and if your camcorder doesn't support uncompressed what happens is it compresses the video during shooting for storage on the media while decompressing it and outputting to HDMI, then the Magewell compresses the stream again and sends it over USB, Double loss which usually leads to incompatible framerates.
    So the camera I am using is a Sony a6300... mid range camera that is used to shoot a lot of video for people.. but I have never read or heard of it compressing the video..
    I would think not though..

    https://www.bhphotovideo.com/c/used/1222773/?gclid=Cj0KCQjwoInnBRDDARIsANBVyATnLIhS4m_...&lsft=BI%3A514
    Off course it compresses to store on the card (XAVC, AVCHD, MP4), But from the link you provided and looking at the specs it looks like it has some kind of uncompressed output (4:2:2 8bit, nowhere near true uncompressed, 4:4:4 10/12bit).

    External Recording Modes: 4:2:2 8-Bit (Not sure if it's throu HDMI or USB)
    UHD 4K (3840 x 2160) at 24p/25p/29.97p
    Full HD (1920 x 1080)24p/50i/50p/59.94i/59.94p

    Compressed Recording Modes:
    -XAVC S:
    UHD 4K (3840 x 2160) at 24p/25p/29.97p [60 to 100 Mb/s]
    Full HD (1920 x 1080) at 100p/120p [60 to 100 Mb/s]
    Full HD (1920 x 1080) at 24p/25p/29.97p/50p/59.94p [50 Mb/s]
    -AVCHD:
    Full HD (1920 x 1080) at 50p/59.94p [28 Mb/s]
    Full HD (1920 x 1080) at 24p/25p [17 to 24 Mb/s]
    Full HD (1920 x 1080) at 50i/59.94i [17 to 24 Mb/s]
    -MP4:
    Full HD (1920 x 1080) at 50p/59.94p [28 Mb/s]
    Full HD (1920 x 1080) at 25p/29.97p [16 Mb/s]
    HD (1280 x 720) at 25p/29.97p [6 Mb/s]

    My guess is you are using the wrong output mode.
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