Synchronized LM-Cams in live production software (OBS, WireCast, VMix)

Updated: Dec 7, 2021

Three LM-Cam's using different HX2 encoding formats (HEVC, H.264, and H.264 with low latency) were added as sources in live production software. The three cameras live streamed an online stopwatch displayed on a monitor. The goal was to measure the delay between streams. Live production software usually requires some adjustments when using multiple cameras. Having more cameras generally means more adjustments.

Test results and recommended settings when using LM-Cam are listed down below.


NDI Smartphone App LM-Cam

https://www.lm-cam.net/?lang=en


Testing Environment

Network: Flets Hiraki Cross (10GB)

Smartphones Used: iPhone 13 x 1, iPhone 12 x 2

* Wi-Fi from the same network was used

LM-Cam App: 1080@29.97, bit rate 20M

Camera: JVC 550 x 1

NDI Converter: Magewell Pro Convert SDI Plus x 1

PC OS: Windows 10

CPU: i9-9900K; Memory: 32GB; GPU: GTX 1660 Super

Live Production Software:

- OBS: 1080@29.97

- WireCast: 1080@29.97

- vMix: 1080@29.97


Method

Live footage of an online stopwatch was streamed from three separate LM-Cams and one JVC camera (via an NDI converter) into live production software (OBS, WireCast, vMix). Footage was regularly checked. Stopwatch times were recorded and later compared.

* The smartphones were connected to the same Wi-Fi network.


Online Stopwatch used for testing: https://stopwatch.onl.jp/


Results

The JVC via NDI converter was established as the baseline. The three LM-Cams were each set with different encoding formats (HEVC, H.264, H.264 with low latency). Times from the LM-Cams were compared against the converter.

* Results will likely vary depending on equipment and environment.


・OBS

HEVC was stable and had the least amount of delay. H.264 was a close second.

Recommendation: make sure Latency Mode is set to "Low."


・vMix

Similar to OBS, HEVC was very stable with little delay. There was a small amount of delay with H.264 (within a frame).

Recommendation: no settings have to be changed.


・Wirecast

HEVC once again performed the best. H.264 was also stable and usually within a frame.

Recommendation: set Timestamps to "Generated by WireCast."


Summary After testing the HX2 encoding formats supported by LM-Cam in live production software, HEVC was found to be the most stable and reliable.

* HEVC drivers may have to be installed when using Windows with LM-Cam.


It is possible to use LM-Cam without worrying about making a lot of adjustments to the delay.


OBS is free and a more than capable option for many users. However, since there is no official NDI support, a third-party plugin (Palakis/obs-ndi) is required.


We highly recommend vMix or WireCast for advanced or professional users.

NDI Smartphone App LM-Cam

https://www.lm-cam.net/?lang=en

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