Live Video Input Thoughts
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    gmint
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    Live Video Input Thoughts

    by gmint » Mon Jun 03, 2013 7:03 am

    I just wanted to share a few insights that I've had recently while really working with getting live video into Modul8. Currently, I'm using a Blackmagic Decklink Pro (via HDMI) and a Logitech USB webcam into a MacPro that is, in turn, driving 5 720P displays and 1 1024x768 display. Initially, when tried the Decklink, I was not impressed with the framerate. The quality was not bad, but the framerate was really what I would call unacceptable. The same could be said for the Logitech cam except that the quality was also awful. After much tweaking, I discovered a few things that I haven't really seen documented in a particularly concise manner. Those things are as follows:

    • In my experience the quality slider in Modul8 really needs to be set about 90% up (to the right) or better. Anything less is practically unusable and really doesn't seem to minimize the hit on the processor anyways. I don't know if others have had different experiences, but this is what I've seen.

    • The Low / Default / High radio buttons again really need to all be set to high to get usable quality video.

    • 8-bit 4:2:2 Uncompressed or 10-bit 4:2:2 is the best codec for the Blackmagic card. 10-bit 4:2:2 seems to use just slightly more processor but doesn't really seem to result in noticeably better quality, so it's probably not worth using unless you really need it for some reason. This is just my experience, but I asked this question in this forum and didn't get a response so I'm posting it here if anyone has the same question.

    Personally, I was very pleasantly surprised at the quality of live video that I can play through Modul8 when using the aforementioned approach. I have no problem using the source from the Decklink and the Logitech simultaneously. That said, I do want to say that I really feel like this whole area could be better described in the dialogs or in the manual. I know that I have really shied away from using live video in the past because of what the default settings would give me in terms of quality and framerate whenever I tried some sort of video input. It seems to me that the defaults ought to offer the settings you would probably want to use, not something that will make the user think that the program sucks at live video input (which is exactly what it has done to me for several years).
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    lotech
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    Re: Live Video Input Thoughts

    by lotech » Mon Jun 03, 2013 11:31 pm

    It would be great if Modul8 added native Blackmagic support in app and not just use Quicktime Capture. That would likely bring down CPU usage and minimise delay.
  • vanakaru
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    Re: Live Video Input Thoughts

    by vanakaru » Tue Jun 04, 2013 9:40 pm

    I have great experience with Matrox MXO2 mini with analog (S-Video) and HDMI capture. Latency is even acceptable for lip-sync.
    I think 8bit 4.2.2 uncompressed is the most usable.
    BTW Modul8 performs better than Quicktime(and Isadora) with this device.
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    gmint
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    Re: Live Video Input Thoughts

    by gmint » Tue Jun 04, 2013 11:03 pm

    vanakaru wrote:I have great experience with Matrox MXO2 mini with analog (S-Video) and HDMI capture. Latency is even acceptable for lip-sync.
    I think 8bit 4.2.2 uncompressed is the most usable.
    BTW Modul8 performs better than Quicktime(and Isadora) with this device.


    If it wasn't clear in my initial post, I'm very pleased with the latency and the framerate from both of my sources. And, as I also said, I concur that 8-bit 4:2:2 is the format of choice for live video.

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