Isadora 2.0 Video Capture - Expertise and Opinions Needed

  • I'm starting this thread in response to a recent thread here and other threads where video capture, specifically in relation to Blackmagic devices have come up.

    First, thanks to @Fred who supplied me with some sample code that uses the Blackmagic API in a recent post. That's very helpful, and I'll be taking a close look at it in the coming days.
    But to summarize the history of live capture on Mac OS: for many years, Isadora used QuickTime to capture. This system offered a function that would display a "Settings" dialog. This dialog allowed you control specific settings for the device from which you were capturing. Some time ago (one year?) people with Mac Book Airs, and the newer Mac Book Pro Retina machines, could not capture from their internal web cams because QuickTime no longer "saw" them. At that time, I switch to a more recent (though not the _most_ recent) system called QT Kit. This new system saw the internal web cams that QuickTime couldn't see which was obviously necessary. But, QT Kit _does not_ offer the settings dialog that QuickTime offered. So the "Settings" button in the Live Capture Window was disabled... which lots of people weren't too happy about.
    At this point, to ensure that professional users can capture effectively from Blackmagic hardware -- which seems to be an industry standard -- we need to make a further change. I want to get this into Isadora 2.0 if at all possible. I am however nervous about the release date slipping because of this, but I'm going to see what I can do.
    There are two options: **_replace_** QT Kit Capture with Apple's newest Apple system, called "AVFoundation" or _**add**_ support for Blackmagic's proprietary API.
    AVFoundation Advantages: the most current system, should give excellent performance
    AVFoundation Disadvantages: we will lose compatibility with many older devices; like QT Kit Capture, there is no "Settings" dialog
    Blackmagic Advantages: we can access certain settings and ensure that we can capture at 1080 at 30fps.
    Blackmagic Disadvantages: only accesses Blackmagic hardware

    Keep in mind that Blackmagic support we be **in addition to **QT Kit Capture. But if we move to AVFoundation, it would **replace **QT Kit Capture.

    (The ultimate solution would be to support all four systems: QuickTime, QT Kit, AVFoundation and Blackmagic. But I simply don't have the programming resources (i.e., me) to do this and get Isadora 2.0 out the door on in November.)

    Given that I only use Isadora, and that many of you use multiple software tools, I am seeking your advice and/or opinions on these topics:
    1) For software that uses AVFoundation, what pluses or minuses have you encountered? Do you know of important hardware that AVFoundation does not work with AVFoundation?
    2) For software that uses the Blackmagic API, , what pluses or minuses have you encountered? What settings do you need access to? Just being able to select the right format? Or?
    3) Given a choice between A) replacing QT Kit Capture (the current 2.0 system) with AVFoundation or B) adding direct Blackmagic support, which is more critical?
    I appreciate whatever insight or thoughts you all have to offer.
    Best Wishes + Thanks in Advance, Mark

  • Hi Mark,

    This isn't answering your questions, but I'm curious how all this affects Windows users?

    Related:  I wasn't able to get any of the portable BlackMagic stuff to work on Windows, so I went with the Matrox MXO2 Mini as a capture device.  It's a great little unit and I do get the settings dialog in Isadora when using it. Many of the higher resolution settings don't actually work in Isadora, but the Matrox does support them and they would be available if Isadora for Windows did.

    Looking forward to the next beta!

    Many thanks,

  • Hi,

    On windows, I think the biggest point to use BM's API is that this is the way you manage to get the less latency ( less than using directshow ).
    And for what I experimented it was lighter for the system ( I have tried with 3 x 1080p30 capture streams ) when using BM's API too.
    As Blackmagic is becoming more and more popular ( due to their prices... ) I have the feeling it would make sense to had a "native support" of it on Isadora.
    All the best

  • @CitizenJoe

    Did you tried the Usb3 Intensity Shuttle ? I used to work with it in isadora.
  • Beta Platinum

    I am really happy with my BM Intensity shuttle USB3. So every support from Isadora is much apprechiated.

  • Hi, I didn ´t managed to get my intensity usb3 work properly in isadora. Intensity usb3 drivers for osx sucks ! I always use blacksyphon free app to get live video into isadora. But i get vid-cpu stream. For the moment i only capture composite video so it´s not a huge load for my mac. Native blackmagic support would be a great option for me ! Best Philippe

  • My preference would be for AV Foundation as I've no historical equipment baggage and would be purchasing AVF compatible equipment.

    This link floated past in my Twitter stream and it might be of interest in this discussion and may make it easier to support BMD equipment by just using Syphon.

    Black Syphon - [](
    This simple, free utility makes it possible for any [Syphon]( enabled software to efficiently send and receive video streams to and from [Blackmagic Design]( hardware devices such as the Intensity Pro, Intensity Shuttle, DeckLink series, MiniMonitor / MiniRecorder, and UltraStudio 4k.

  • For simplicity and a slow change I would suggest an actor for windows and mac that uses the BM API, just an actor, not changing the capture system. From here you can evaluate how many people use it and get it out fast. AVFoundation and native capture on windows are a must for the future, pretty soon it will be irrelevant to support ageing hardware and capture gear. Apple have been making it harder and harder to use for years, Izzy should keep up, it will be harder to buy also.


  • I agree with @Fred on the dedicated actor idea.

    I would also feel practicle that video capture is fully actor based like all other functions.

  • @keftaparty,
    I did try the Usb3 Intensity Shuttle; I was really hoping it would work, but it didn't. To be fair, this was about a year ago and I've no idea if the situation has changed.

    The MXO2 Mini basically worked out of the box, although I had to spend some time on the phone with Matrox support (they're excellent!) to get full HD working properly - I had downloaded the version of the drivers that appeared to be the right ones, but were not.

  • Tech Staff

    I used a BM usb3 Intensity Shuttle in a show with Isadora back in March.
    Setup was tricky because the Shuttle is very specific about settings, and at first it was unclear the 'real' format I was receiving to the Shuttle (60i vs 30p)
    In the end it worked great, and I was able to change capture resolution very last minute to gain a little system performance.

    I don't know what the API offers, but what I found was that the BlackMagic software didn't give any information about incoming signals unless the settings were exact.
    If the hardware is aware of an input (not sure it is unless settings match), it would be great if it would tell us something about it so that we might be able to check the settings.

  • Across the whole line of blackmagic capture boxes they do not auto select resolutions. For any advanced user (or at least one that knows what they want to capture) this is no problem, if you know what you are plugging into it then set the input to match. I dont understand why people find this difficult or a fault, @Dusx when you say "Setup was tricky because the Shuttle is very specific about settings" - meaning you have to tell it what you are capturing- I am not sure what you mean? Shouldn't you know what signals you have?

    The using the API gives a performance boost- for me less than 1/4 of the cpu use capturing the same format from qtkit vs the API. It also gives the settings that qtkit took away, although @Mark this has to be programmed, but would suit an actor in its structure.
    @[CitizenJoe](  mac or PC? the USB3 devices from BM require a full bandwidth USB3 bus, many manufacturers cut corners here and their chipsets dont stand up, less of a problem now that the integrated USB3 chipsets are better- OSX drivers for USB were and are in Beta, but now the beta is a very useable version.
    Anyway as the price is so low, they are everywhere, it is worth supporting the API directly as there is such an improvement increase.
  • Tech Staff


    In my case I was interfacing a Motion capture software from another machine, that I had never worked with before. The motion capture technician had difficulty telling me what format I should expect, so I spent some additional time on her machine and my own figuring out how to get a supported feed from that system. In this case it was a software issue, mostly since it was unclear what the motion capture software was rendering out to, but an autoscan feature that could have told us where we were with things would have been nice. Not necessary, but nice.

  • i am with fred, that a bm actor would suite the most people

    even that i am not a huge fan of there products
    in fact having 2 actors 
    splitting the control in one (resolution / input port, …) // local /global mode
    and having a mutable bm_device_output (vid-gpu / CI / vid-cpu) would be perfect
    so we could grab the input signal in different scenes without the trouble of different settings etc.
    like a mimikri of the video device setting dialog
    having the option too address multiple logical devices ( 2x mini recorders, 1x 4 ch card) would be pro feature as well
    i like the aja gear and would love to see a native support (better signal analyzing, internal keyer, downconverter )
    but this seams to be a 2.5 feature, if it happens at all ??
    thanks for polling our opinions

  • it would be nice to get the Settings dialogue back in Live Capture Settings. i use a Canopus capture device, but also have a BMD mini recorder that i haven't managed to get working yet.

  • hi all i'm working with blacksyphon and BM thunderbold shuttle and it´s pretty cool... but every solution which would decrease latency will be perfect for me... I'm not enough aware of api's and Qt versus AVF stuff, but for a user which plays with live cams ( 16 for me) a lower latency still the best solution...

  • Hi, for me capture is all about minimum latency. I have both the Thunderbolt Ultrastudio Pro and Mini Recorder and tested on 2013 MacPro (8 core / D700). Using Millumin, which utilises the BM API, I get 3 frame delay with the Ultrastudio Pro at 1080 / 60p = 50ms. Mini Recorder has 4 frame delay, but at maximum of 30p only = 133ms. I tested the Ultrastudio Pro with Izzy 2.0 and got 4 - 4.5 frame delay. I hope to test the Ultrastudio Pro with a genlocked source when I can get my hands on a 1080 / 60p sync generator.


  • I too use the BM ultra studio-TB, but have a 2012 MBPro with only one TB port.  So if I want to use the Matrox 3Head2go I'll need to also get a USB3 Intensity Shuttle.  Aaargh.  But it sounds do-able for corporate shows, which I do a lot of.  133ms is not a small delay but is definitely liveable.  re; the OP, BM support would be a good thing, I'm seeing there gear more and more with AV/Rental house company gear.

  • Dear All,

    I am just wanted to report that, after two weeks of non-stop work, I have integrated support for direct capture from Blackmagic hardware into the Live Capture Settings window. I am seeding this build to some of the top users who I know make use of Blackmagic devices.
    But, If you are are _actively_ using Blackmagic hardware and are willing to give this build a go, I am willing to let you try it. Not everyone on the team has Blackmagic hardware, and so we do need some extra help ensuring this version works well for everyone.
    Please only write me if you are willing to work with something that is potentially _very_ buggy!!!! It is very lightly tested, and I cannot make any guarantees at this point. You must indicate in your mail that you fully understand that this is in alpha test at this point, OK?
    Best Wishes,

  • Great, thanks Mark. Coming late to this party but very excited about BM integration... will request a test version, and will have an exorcist on standby in case the new code has unwanted metaphysical consequences.

    Take care