Not sure if this is the correct forum category, but it didn't seem to fit anywhere else.

I've been trying to capture using a Blackmagic Decklink SDI card with Kdenlive. Initially, using the Setup Wizard, the Decklink SDI card was not recognised. However, using Record Monitor and the Capture configuration after clicking the Wrench symbol, I was able to setup the card.

I must admit I didn't find the capture all that intuitive. Kdenlive was unable to control the J30 Digibeta deck, even though I had an RS-422 cable connected. There was no way to set in and out points from within Kdenlive. During the capture RAW files seemed to be created, unmuxed so video and audio was separate. Is there some way to change this? Ideally, I'd like to capture a muxed file of some description. IMX50 would be nice. How do I actually view/read these captured RAW files in Kdenlive? They didn't seem to be recognised by the software.

Lastly, it wasn't possible to change the frame size of the capture. I seemed to be stuck with 720x576, whereas ideally I was looking for 720x608 so the VITC was retained. I also couldn't see a 16:9 Anamorphic option. I am quite new to Kdenlive, so if I am missing something, please do let me know.

If Kdenlive cannot perform the type of capture I am looking for, are there some other open source, Linux based options using the MLT framework (or Gstreamer I guess) that I might investigate? It'd be great if there was something like straightforward and dedicated to capture with via SDI.

I should have also added that I have tried Blackmagic's supplied Media Express software for capturing. This actually does a reasonable job. It has deck controls via RS-422 and one can set in and out points for the capture.

However, the capture codecs are pretty limited - uncompressed 10-bit YUV, uncompressed 8-bit YUB, RGB and MJPEG. I've been using the uncompressed 10-bit YUV, but then need to transcode using FFmbc to IMX50.

Unfortunately Media Express 2.3.1 for Linux does also will not capture 720x608 for the VITC. I was also hoping that by using something like Kdenlive, I could have access to all the codecs installed on my machine.

http://stream0.org/2011/06/24/blackmagic-decklink-sdi-and-linux/

The current release version of Kdenlive was the first to support decklink, and consequentially it was mostly an experimental hack. That said, they have done a lot to improve it over the last few weeks, so if you build your own from the development tree, you will find it is quite a bit better, although I wouldn't consider it finished by any means. Be aware that if you do so, you will need to build the development version of MLT as well since the code for decklink capture was moved out of kdenlive and over to the MLT library.

As for your other issues:

- Deck control via RS-422 : Not supported by kdenlive that I am aware of. It _might_ support limited deck control over firewire, but I'm not sure. (Never tired it.)

- Codecs : MPEG2 is the only codec the development version currently captures to reliably

- VITC : I don't know of any linux based software yet that utilizes the support for capturing VITC that is available in Blackmagic's SDK.

- Media Express : Version 3 is to be released this month. Hopefully that will make more options available. Will have to wait and see.

- IMX50 : If you want to capture directly a FFMPEG / FFmbc based codec (provided your system is fast enough to encode real-time), you could pipe video into ffmpeg from the decklink using this tool -> https://github.com/lu-zero/decklink-ffmpeg (Note: it doesn't support all capture options, but it's easy to hack them in. I have a patch if you're interested)


You can also follow this bug: http://www.kdenlive.org/mantis/view.php?id=2130