simtk.org

Hi,

I'm running a study on the field to collect data from athletes running a sidestep cutting. Would you have any suggestions on some factors that may improve upload speed? I'm using a router with a 4G sim card. Pretty sure is is mostly on the internet speed and signal strength, but would like to hear from your experience. Would a more powerful computer improve that, or is it unlikely? I am having from 40s to 5 min for a 5-sec trial to upload.

Thanks for the support

Hello yuri,

If I'm not mistaken, the phones upload the videos to the OpenCap servers and they get processed there in a queue. The pc just allows us to retrieve that processed information to view it. Therefore, using a better pc might not help. However, its okay to continue recording another trial once the indicator turns yellow. You can check back after some time to view the end results (after the indicator turns green).

I have also noticed longer wait times recently compared to when I started using OpenCap a few months ago. This could be due to the large number of people using the service resulting in long queue times for processing.

Someone correct me if I'm wrong.

-Jeevin

Thanks Jeevin, I noticed that they are taking longer to turn green indeed. However, my main issue is the wait time between trials. The fact the we are only able to record a trial after the previous one is uploaded giving me trouble in a fast-pace screening battery in football clubs.

Hi Yuri,

The only way to improve the upload speed is to connect the phones to a better network connection. We have had success if each phone is using data (eg 4G) and has good signal, but if you connect multiple phones to the same hotspot, things are very slow. The hotspot tends to throttle the connection speed of the second device (~5x on ours). The webapp requires minimal bandwidth (just sending start/stop requests to the server), so putting it on a hotspot alongside a phone is usually ok, as long as the phone gets the fast upload speed of the "primary" device (you can set this on some hotspots). You can run network speed tests on all the devices to check (I've found that much less than 10mbps upload speed makes for a slow data collection, but there are more factors than just this number).

The new version of the ios app (1.6 (25) or newer) has an upload speed bar that shows up when you stop a trial. You can see if one of the phones is significantly slower than the other one and diagnose connectivity on each device.

We are aware that data collection is slow in these poor-connection environments. We plan to develop a feature to improve this, but it will be several months away.

Correct, the processing queue is growing as more people begin to use the platform. Our compute resources are limited, but data still tends to finish processing within a few hours.