Our freestyle ski team is looking to invest in a system that allows athletes to immediately review their competition ski runs with their coach after they get to the bottom. While they're playing back the video of their run, the camera will need to be available to shoot the next athlete. In an ideal world, a tethered camera would record directly and automatically to a folder on a laptop so that the athlete would be able to replay their run independently of the camera, leaving the camera free to keep recording the next athlete.

I've experimented with a Canon 5Dmk4 and the EOS Utility, which seems to automatically detect when the camera finishes shooting a video, and then prompts you the option of saving that file to your computer. This involves a lot of manual interaction, can take 30+ seconds to transfer a minute of footage, and ties up the camera during that transfer, preventing you from shooting the next skier if the transfer isn't completed in time. It's also a bit tedious and requires a coordinated effort between the videographer and the coach doing the video review.

We are hoping to invest in the GH5 due to it's slow motion capabilities, but am uncertain if this will pose new challenges (i.e. file sizes), or offer any solutions.

I'm familiar with the Ninja recording monitors being able to save to an SSD, but I'm curious of a solution that would allow me to instantly view recorded footage on a laptop, while leaving the camera free to shoot more video. I'm open to anything that would allow us to achieve what we're after as cheaply as possible!

  • What is your budget? Jan 3, 2018 at 23:17
  • @MichaelLiebman Our budget is as small as we can get away with. We're a non-profit organization with limited resources, but we'd like to be effective at getting the job done, as it would be a very important training tool. Ideally, under $1000 for the replay solution, excluding the camera body and lenses. We're willing to consider anything, even hotswapping SD cards from the camera to a laptop and from the laptop back to the camera between every run, but I feel like there has to be a better way. Jan 7, 2018 at 3:07

3 Answers 3

  1. look for a camera that can trigger recording on/off by it's HDMI output (used when you have something like a atomos recorder), not sure which current models can/can't but any dslr that's marketed as a video camera should do it.
  2. run a hdmi cable to a hdmi capture box ( I think HDMI can do 15m without a repeater )
  3. hook the capture box to a laptop
  4. use software that will start recording when the camera presses record.
  5. use software like stream to me
  6. coaches can use another device ( tablet/laptop etc ) to display the recorded run

Using this setup you can have the camera recording runs while multiple people can stream any previously recorded run at the same time. As long as the software can detect the record flag from the camera the whole process is automatic, playback can begin for a file the moment after recording has stopped.

I'd recommend a black magic thunderbolt ultra studio mini for the capture box, it comes with Media Express software which will auto trigger when it receives a record flag from the camera. The mini is bus powered & small so it's keeping your cables down & means everything is running of batteries if needed

Stream to me is an iOS app for the playback but the companion app Serve to me is Windows & Mac & that lives on the laptop watching the folder that Media Express records too. Alternatively I'm sure a bit of google will find an android substitute for this part of the link.

All that reasonable cheap, meets the need of recording while simultaneously playback (actually a pretty hard thing to do without spending big bucks) & once it's setup should take care of itself, while you concentrate on practice.


If the camera allows you to output live HDMI while recording, an idea would be to capture the live video with a capture card, and then record every athlet on the computer.

A capture card doesn't cost too much, there are USB HDMI external capture cards that are pretty good even for a low price.

For recording, I'm not sure of what softwares are available, but it wouldn't be difficult to go completely custom. A simple script of one line could launch ffmpeg and record the input interface until you stop the recording. This way you can have a h.264 output file ready as soon as you stop recording. I would recommend using two computers for this, one handling the recording and the other one for playback. You could easily access files from the other computer using the network.

This solution would require manually starting and stopping the recording on the computer, but if you want to avoid the time needed to transfer the recording from the camera to the computer, I'm not sure if there are other solutions (without paying for a complete live replay system, which would be an overkill other than a waste of money).

  • Thanks! I'm not quite sold on this solution due to the multiple computer setup, hardware, and the level of manual coordination needed to start and stop recordings. It may be too much for this particular environment, which is fast paced and chaotic with potentially inclement weather. The more simple the better. Jan 7, 2018 at 3:15

This is a pretty low-tech solution but it would definitely work: buy more than one memory card for the camera and just switch it between runs - shouldn't take more than a few seconds to get the camera recording again and then you just pop the card with the previous run on into your laptop and then it's just how long it takes to find the file before you can review the run.

As I said, low tech but it definitely works and is practically idiot-proof.

EDIT: Ah - sorry, you already suggested this yourself in your first comment! Apologies :D

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