What is RTMP? The Real-Time Messaging Protocol: What you Need to Know
Table of Contents
Online video streaming continues to become more popular due to the consistent development of supporting technology. One particular online video streaming technology that has played an important role in the rise of this industry is RTMP.
RTMP has served as a solution in several different steps of the live streaming process, and its role will likely continue to shift as technology evolves.
In this post, we are going to break down everything you need to know about RTMP and how it relates to live streaming. We will discuss what RTMP stands for, what Real-time Messaging Protocol is, and a common misconception before we dive into the more technical side of the protocol.
We’ll take a look at its specific purpose in live streaming, different variations of the video protocol, and the basics of RTMP encoding. To wrap things up, we will discuss how RTMP works with Dacast.
Table of Contents
- What is RTMP?
- RTMP at a Glance
- How Does RTMP Ingest Work?
- Is FLASH Dead?
- RTMP Protocol Variations
- RTMP Encoding
- RTMP vs. RTSP: What’s the Difference?
- How to Live Stream with RTMP on Dacast
- Final Thoughts
What is RTMP?
RTMP stands for “Real-Time Messaging Protocol,” and it is part of the technology that makes live streaming possible. This Transmission Control Protocol-based technology was originally developed by the predecessor of Adobe to work with the Adobe Flash player.
Originally, RTMP was used to transmit content between a video player and a hosting server, which was referred to as “RTMP delivery.”
Today, its purpose is a bit different. In terms of the most modern live streaming setups, RTMP’s primary role is to deliver content from an encoder to an online video host. This RTMP function is referred to as “RTMP ingest.”
In the context of its new role in live streaming, RTMP is both important and powerful. RTMP is capable of low-latency streaming, which is a major plus for broadcasters who are streaming major events in real-time. It is also known for its minimal buffering, which truly enhances the user experience.
Aside from simply delivering files from the encoder to an online video host, RTMP technology plays a role in adaptive-bitrate streaming. It contributes to the technology that makes it possible for users to fast-forward and rewind videos. RTMP also plays a role in some web conferencing tools.
There are several variations of this protocol, which we will discuss further along in this post.
RTMP at a Glance
- RTMP is a live streaming protocol that transmits video files from an encoder to an online video hosting platform.
- RTMP has been replaced by HLS for its original role in live streaming, but it now serves another important role.
- AAC-LC is the best audio codec for RTMP encoding, but AAC is also supported.
- H.264 is the best video codec for RTMP encoding, but MP4 and x264 are also supported.
- RTMP ingest supports the use of low-cost encoding tools.
- RTMP ingest on Dacast automatically supports conversion to HLS on iOS, Android, and all browsers.
- The protocol has several distinct variations.
- Broadcasters prefer using RTMP streaming since that has low latency.
How Does RTMP Ingest Work?
There are three distinct parts that make RTMP ingest work:
- The handshake
- The connection
- The stream.
This sequence of events happens in just a few seconds.
The process is highly technical, but broadcasters don’t generally need to worry about what goes on behind the scenes as long as they’re using a reliable video hosting platform.
However, here’s a quick breakdown of the RTMP ingest process.
The handshake phase involves three chunks of data being exchanged between the client and the server. The first chunk of data lets the server know what variation of the RTMP protocol is being used, and the second has a timestamp.
The server confirms receipt of the first two chunks before the client sends the third chunk. After this third chunk is received, the connection begins.
The connection phase involves a coded dialogue where the client sends a connect request and the server responds with an all-clear. The final phase, the stream, starts once the client responds to the all-clear with an appropriate signal.
Is FLASH Dead?
One common misconception is that RTMP is dead. Although Adobe Flash player, the video player that originally used this technology is practically dead, RTMP itself is still valuable in other roles in live streaming.
The Adobe Flash Player is no longer widely used as it has been replaced by the HTML5 video player. As we mentioned, RTMP was used to connect the Flash player to an RTMP delivery server. The HLS protocol has taken over this role with the HTML5 video player.
Basically, RTMP delivery is dead but RTMP ingest for HLS is not.
Since technology is evolving so rapidly, RTMP will likely “die” in the future, but for now, it remains important in the realm of live streaming.
RTMP Protocol Variations
There are several variations of RTMP, including RTMP proper, RTMPS, RTMPE, RTMPT, and RTMFP. These video protocols serve slightly different purposes in the world of live streaming.
Let’s take a look at what exactly each of these streaming protocol variations has to offer.
1. RTMP Proper
RTMP proper is the most standard version of the RTMP protocol.
RTMPS streaming is the protocol that is related to secure streaming since it uses an SSL connection. Facebook Live uses this variation of RTMP in order to protect streamers who go live on public internet servers.
RTMPE is the variation of the protocol that is encrypted with Adobe’s security standards. Streams that user RTMPE are considered extra secure since their code is not accessible without the proper clearance.
RTMPT is the version of the protocol that is designed to bypass firewalls. This is made possible by encapsulating the protocol in HTTP requests.
RTMPT does not perform as well as RTMP on its own, so this protocol should only be used as an alternative if you need to bypass a firewall.
Real-Time Media Flow Protocol (RTMFP) is used in part with some peer-to-peer technology that allows users to interact.
This technology is the basis of many video conferencing tools and social media apps with video live stream chat features. The reason that this protocol is preferred for this use case is that it requires less data, which keeps bandwidth costs reasonable.
It is important to note that this protocol is not suitable for file sharing as it was only designed for peer-to-peer use.
As we mentioned, the most modern use for RTMP technology is transmitting video content from the encoding software to the streaming platform. In order to stream with a setup that uses the RTMP protocol in this fashion, you must use an RTMP encoder.
Luckily, many of the top encoders on the market support RTMP, so you shouldn’t have trouble finding one that works for you.
Which Encoders Support RTMP?
When it comes to RTMP encoding, broadcasters can choose from a wide variety of software and hardware encoders. There are options for every need and budget.
Here is a list of a few of the top RTMP encoder options:
- OBS Studio: OBS Studio is a free, open-source encoding software that is perfect for broadcasters who are new to the game. OBS offers a custom version for Dacast users.
- Wirecast: Wirecast is a popular software encoder from Telestream. This software starts at $599, making it better suited for more advanced broadcasters.
- VidBlaster: VidBlaster is a live streaming software with editing, mixing, and encoding capabilities. It is a great option for broadcasters who are looking to add a professional touch to their streams. The software starts at $9/year.
- vMix: vMix is another live streaming software with encoding capabilities with plans for every budget. Plans range from free to $1200.
- TriCaster: TriCaster is a series of encoding devices from NewTek. This series includes both portable and stationary options.
- Teradek: Teradek is a hardware company that offers an assortment of encoding devices.
For more information on how to set up an RTMP encoder, please check out our Encoder Setup Guide.
RTMP Apps for iPhone
In addition to the encoding tools we mentioned above, there are iOS apps that support RTMP streaming from your iPhone. These apps are designed for broadcasting on the go.
Here are a few of the best live streaming apps that support iOS and RTMP:
We’d like to point out that although it’s possible to stream from an iPhone smartphone, streaming with professional-grade equipment is ideal. However, if you’re streaming on-site and don’t have mobile live streaming equipment, it will get the job done.
For more details of iOS apps that support RTMP streaming, please check out our iOS RTMP App comparison.
RTMP vs. RTSP: What’s the Difference?
RTSP, which is short for “Real-Time Streaming Protocol” is another protocol that is used for online video streaming. It is considerably less popular than RTMP, but it is still important.
The main difference between RTMP and RTSP is the part of the live streaming process that they are each responsible for. RTMP transmits the video from the encoder to the video player whereas RTSP controls commands between the viewers and the video player.
RTSP is the technology that makes it possible for viewers to use the “Play,” “Pause,” “Rewind,” and other player commands.
Since they play very different roles, both of these protocols are essential for live streaming.
How to Live Stream with RTMP on Dacast
Dacast automatically uses the RTMP ingest and is compatible with any RTMP encoder. That means that RTMP is a Dacast default rather than a choice.
What Dacast does not support is RTMP delivery or the Adobe Flash player. The reason for this is that we use the HTML5 video player, which is the more modern alternative. The HTML5 video player is what makes all-device streaming a possibility.
If you want to learn more about how to set up a live stream on Dacast, please check out our Introduction to Live Streaming guide.
RTMP plays an important role in several different aspects of live streaming. Without this technology, it is hard to say where the online video streaming industry would be today.
As we wrap things up, it is important to keep in mind that RTMP is not dead, but it simply plays different roles than it once did.
If you have any questions about how RTMP works, please contact our knowledgeable 24/7 support team. We will answer your questions and provide you with the materials you need to understand this technical topic.
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In the meantime, please check out the Dacast Knowledgebase, which is a special part of our site that includes documentation on how to use each and every function of our platform.
Thanks for reading, and happy streaming.
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