In Vol.02, we will explain the video transmission protocol, which is always confusing to PTZ camera beginners. From the classic “RTMP” to the latest “SRT,” understand the meaning of video transmission protocols allows you to review and choose the PTZ camera that suits your purpose.
“RTMP” for YouTube livestreaming
RTMP is used by many live streaming platforms such as YouTube. It is used for live streaming and on-demand streaming, making it easy to deliver high-quality video and audio. RTMP also exists as “RTMPS” which has enhanced security, but please note that YouTube Live currently only supports streams from compatible devices (YouTube’s help page does not have a description of RTMPS). (This is expected to be fully transitioned in the future.)
The similarly-named “RTSP” is characterized by lower latency streaming than RTMP. This is mainly used as a protocol for surveillance PTZ cameras. If you are using YouTube or Facebook for live streaming purposes, you do not need to be particularly aware of camera compatibility with this protocol.
Features high quality and low latency
SRT is an abbreviation for “Secure Reliable Transport.” This is a protocol that allows video to be transferred from a remote location in high quality. It was originally made open source by Hi-Vision, a company that produces encoders, in 2017. SRT is known to be most used in remote production because it has good security, low latency, and can send high-quality images to remote locations.
Setting up SRT is almost the same as RTMP on the sending side, so it’s not that difficult. However, since the receiving side must open a network port, a certain amount of network knowledge is required. Photron is providing a cloud gateway service to easily use SRT, and if you are not familiar with network technology, you may be able to use such a service.
NDI is the most popular IP transmission technology for connecting video equipment. There are two main types of NDI standards installed in remote cameras: “Full NDI (High Bandwidth NDI)” and “NDI|HX”. Full NDI requires support at the chipset level, so only BirdDog and NewTek have released compatible remote cameras. On the other hand, “NDI|HX”, which was introduced in 2017, uses H.264 compression, and a wide range of manufacturers including Sony, Canon, and Panasonic are currently releasing compatible remote cameras one after another.
When NDI|HX first appeared, the image quality was inferior to NDI. If image quality was important to you, you should choose BirdDog and NewTek remote cameras. However, with the advent of “NDI|HX 2” and “NDI|HX 3,” it has become possible to achieve image quality equivalent to NDI. Also, while NDI’s bandwidth is approximately 300Mbps, NDI|HX uses only about 1/3 to 1/4 even when streaming the same full HD signal. In other words, NDI|HX is superior in terms of ease of network construction when using multiple cameras. In that sense, more and more manufacturers are adopting NDI|HX, and BirdDog finally released a camera compatible with NDI|HX 3 at NAB 2023. If you are currently choosing a remote camera that supports the NDI standard, I would recommend choosing one equipped with NDI|HX 3.
SMPTE ST 2110
ST 2110 is a video transmission standard using the IP transmission method. It is a transmission standard that replaces the conventional baseband transmission such as SDI with the IP standard. In the PTZ camera industry, Panasonic’s AW-UE160W/K is the only camera that supports ST 2110. IP conversion using ST 2110 is progressing particularly in large-scale core systems such as broadcasting stations, and NewTek is also selling a converter that converts ST 2110 and NDI. Furthermore, Blackmagic Design has also started selling the “2110 IP Converter 3x3G.” It is expected that the ST 2110 will become more popular in small-scale production.
PTZ Camera Review originally written by Yuto Izumi in Japanese｜Profile
Director of AVC Business Department, Kaminari Co., Ltd. He is skilled and experienced at video production in general, including multi-cam recording and distribution, and works on video production using the latest equipment. In recent years, he has been involved in a wide range of projects, including live broadcasting of the Fukuyama Ashida River Fireworks Festival, which launches the longest floating star mine in western Japan, as well as e-Sports video production such as TOYAMA GAMERSDAY. He also supports students’ video production activities as the executive director of the High School Broadcasting Equipment Exhibition.