[Jim Sustacek]

What have you looked at? What are you looking for?

I think Justin.tv and Livestream.com both offer free streaming plans. You can check them out and see if they will meet your bandwidth needs, otherwise they have paid services too.

On the encoder side, I think Flash Media Live Encoder will work fine for a simple stream, and that is free also.

[Jim Sustacek]

Check the Media Express preferences to make sure you are writing to the correct folder and with the correct codec. (You can also un-check the box to stop capture on dropped frames to suppress those alerts, although if you are not recording live, it’s definitely good to be notified when it happens.)

What’s your disk write speed, using the Blackmagic Disk Speed utility? Maybe your target drive has slowed for some reason (could it be too full)?

I usually record to a regular SATA drive so I can’t use the uncompressed codec, I had to install the ProRes codecs and use ProRes LT:
https://www.jonathangrubbs.com/journal/pro-quicktime-codecs-no-fcp/

Depending on your source footage, ProRes LT might be sufficient for you too, if the other solutions above do not help.

[Jim Sustacek]

Okay, here’s a PlistBuddy terminal command that should do the trick (this will affect all Blackmagic devices for a particular system):

for dict in `/usr/libexec/PlistBuddy -c 'Print :' /Library/Preferences/com.blackmagic-design.desktopvideo.prefspanel.plist | awk '{ print $1 }' | grep com.blackmagic-design.desktopvideo.prefspanel`; do sudo /usr/libexec/PlistBuddy -c "Set $dict:AnalogVideoOutput Composite" /Library/Preferences/com.blackmagic-design.desktopvideo.prefspanel.plist; done

It uses sudo so it will probably prompt for a password when you run it.

And to change it back, just switch Composite to Component in the command:

for dict in `/usr/libexec/PlistBuddy -c 'Print :' /Library/Preferences/com.blackmagic-design.desktopvideo.prefspanel.plist | awk '{ print $1 }' | grep com.blackmagic-design.desktopvideo.prefspanel`; do sudo /usr/libexec/PlistBuddy -c "Set $dict:AnalogVideoOutput Component" /Library/Preferences/com.blackmagic-design.desktopvideo.prefspanel.plist; done

Note: I haven’t tested this beyond verifying the correct option was selected in the Blackmagic preference pane.

[Jim Sustacek]

Same thing happens for me — must be a Blackmagic bug?

There seems to be a workaround:

1) Open /Library/Preferences/com.blackmagic-design.desktopvideo.prefspanel.plist

(I used the Property List Editor app that comes with or within Xcode, you could also use PlistBuddy in one nice terminal command)

2) Change the value for key “AnalogVideoOutput” from “Component” to “Composite” and save the file. (If you have multiple Blackmagic devices, you will find multiple “AnalogVideoOutput” keys in the plist tree.)

3) Re-open System Preferences and you should see the change. The change seems to hold so well, it seems like the only way to change it back is to edit the plist file again!

[Jim Sustacek]

This seems to be good advice, although I was unable to get it to work just now, but other people have reported success:

https://blog.grio.com/2012/01/fast-and-slow-motion-video-with-ffmpeg.html

[Jim Sustacek]

I don’t know anything about the Avid DNxHD codec, but if you have the codec installed and QuickTime Pro can open the files, I would use that to identify your edit points (GUI). Then, assuming FFMPEG can decode/encode that codec, you could use that to do the actual editing (no GUI).

When trimming segments, if you are simply copying the Avid DNxHD codec (no re-encoding), you may have to begin your trim segments on keyframes — at least that is what I have to do with H.264:
https://trac.ffmpeg.org/wiki/Seeking%20with%20FFmpeg

If that’s the case, use ffprobe to find keyframe locations:
https://stackoverflow.com/a/14013439/2096063

Otherwise, you could do a “Lossless H.264” transcode when cutting all of your segments, then you shouldn’t lose quality nor have to worry about keyframes — see here:
https://trac.ffmpeg.org/wiki/x264EncodingGuide

And finally, if your edit segments all have the same codecs and settings, you should be able to use the “concat demuxer” referenced at the following link to join them without re-encoding:
https://trac.ffmpeg.org/wiki/How%20to%20concatenate%20(join,%20merge)%20media%20files

Ultimately, if you went the Lossless H.264 route, you’d eventually have to encode it back to non-lossless so it could be read by other programs. I’ve found “-crf 18” is a great-looking libx264 encoding option.

[Jim Sustacek]

Sonnet has a number of products that might fit your needs:

https://www.sonnettech.com/product/thunderbolt/index.html

If you don’t find the exact Thunderbolt hub you are looking for, you could also try a Thunderbolt PCIe enclosure with two Intensity Pro PCIe cards installed instead of two Intensity Extreme/Shuttle units.

I haven’t done anything like this yet, so you will want to research it further before purchasing (or get a good return policy), but theoretically it should be possible. I would be curious to hear your results if you try this too.

[Jim Sustacek]

Amending my other post, which assumed 240 pixel cropping, here’s a 210 pixel crop:
ffmpeg -f image2 -r 25 -i frame-%05d.jpg <b>filter="-vf crop=1500:1080:210:0"</b> -target pal-dvd output.mpg

[Jim Sustacek]

Here’s a basic command to concatenate your images into a movie, based on this blog post about time-lapse movies:
ffmpeg -f image2 -r 25 -i frame-%05d.jpg -c:v libx264 output.mp4
“-r 25” is your frame rate, and “-c:v libx264” would be your codec/quality settings. Feel free to adjust those or swap in other codec/quality settings you may find around the web.

You should also be able to use the crop filter (format width:height:x:y, see filtering guide here) and the “pal-dvd” target for your PAL DVD encode like this (although I haven’t tried it yet):
ffmpeg -f image2 -r 25 -i frame-%05d.jpg filter="-vf crop=1440:1080:240:0" -target pal-dvd output.mpg

[Jim Sustacek]

We’ve had good success with Epiphan VGA2USB devices:

https://www.epiphan.com/products/frame-grabbers/

The included software can record directly from the device and looks really crisp. The lower-end devices may not give you a full frame rate when capturing higher resolutions, but it’s definitely fine for more static presentations. (Although we can generally get higher frame rates than those listed in Epiphan’s specs.) Also, you can access the Epiphan device signal in many other video encoding programs if you so desire, although the image is less crisp going through them.

Another option would be Wirecast to record/stream a remote screen using their Desktop Presenter utility. Again, it won’t be as crisp as the direct VGA2USB, although you’ll probably get a consistently higher frame rate, and you have more flexibility for outputs and mixing, if you want to get into that.

Otherwise, you’re going to be scan converting or scaling to get it to HDMI/component video, which can get expensive and will probably never equal the quality of the direct VGA2USB signal.