RTMP Streaming: The Real-Time Messaging Protocol Explained

What Is RTMP?

The RTMP specification is a streaming protocol initially designed for the transmission of audio, video, and other data between a dedicated streaming server and the Adobe Flash Player. While once proprietary, RTMP is now an open specification.

RTMP Streaming: A Snapshot

  • Audio Codecs: AAC, AAC-LC, HE-AAC+ v1 & v2, MP3, Speex, Opus, Vorbis
  • Video Codecs: H.264, VP8, VP6, Sorenson Spark®, Screen Video v1 & v2
  • Playback Compatibility: Not widely supported (limited to Flash Player, Adobe AIR, RTMP-compatible players; no longer accepted by iOS, Android, most browsers, and most embeddable players)
  • Benefits: Low-latency and minimal buffering
  • Drawbacks: Not optimized for quality of experience or scalability
  • Latency: 5 seconds
  • Variant Formats: RTMPT (tunneled through HTTP), RTMPE (encrypted), RTMPTE (tunneled and encrypted), RTMPS (encrypted over SSL), RTMFP (layered over UDP instead of TCP)

How Does RTMP Streaming Work?

Macromedia (which is today Adobe Systems) developed the RTMP specification for high-performance transmission of audio and video data. RTMP maintains a constant connection between the player client and server, allowing the protocol to act as a pipe and rapidly move video data through to the viewer.

History of RTMP Streaming

Flash Player and RTMP were the dominant delivery mechanisms for live streaming up until the early 2010s. When used together, these technologies support lightning-fast video delivery with around five seconds of latency. But HTML5 video streaming, open standards, and adaptive bitrate delivery eventually edged RTMP streaming out when it came to last-mile delivery.

So, Is RTMP Dead?

Flash’s end-of-life date is overdue. But the same cannot be said for RTMP. RTMP encoders are still a go-to for many content producers, and 33% of respondents to our Video Streaming Latency Report indicated using it.

Typical RTMP Live Stream Workflow

Content distributors aren’t limited to one streaming protocol from capture to playback. In fact, repackaging a live stream into as many protocols as possible helps ensure broad distribution.

How to Set Up an RTMP Stream

To deliver an RTMP stream across the internet, you’ll need to start with an RTMP-compatible camera or encoder. You may be using an IP camera, software encoder, or hardware encoder. We recommend the free OBS software or the Wowza ClearCaster Pro encoding appliance.

Considerations When Replacing RTMP

The best protocol for your workflow will depend on your use case. You can check out the pros and cons of each protocol in this blog. But to start, we’d recommend comparing your options based on the considerations below:

  • Scalability
  • Latency
  • Quality of experience (adaptive bitrate enabled, etc.)
  • Use (first-mile contribution vs. last-mile delivery)
  • Playback support
  • Proprietary vs. open source
  • Codec requirements

RTMP Alternatives for Egress

For last-mile delivery, Apple’s HTTP Live Streaming (HLS) and MPEG-DASH lead the pack. HLS is the most common protocol in use for live streaming today, employed by more than 45% of participants in our Video Streaming Latency Report. MPEG-DASH is the open-source alternative to HLS and a standard in the industry.

RTMP Alternatives for Ingress

While RTMP is still commonplace for first-mile contribution, even that could change with time. Industry leaders predict that open-source protocols like Secure Reliable Transport (SRT) could become the standard.

Testing Your RTMP Workflow

To try out your workflow, we offer a Test Player with support for MPEG DASH, HLS, RTMP, HDS, and more. You’ll notice that the ‘Adobe RTMP’ tab requires the installation of Adobe Flash Player. That’s because native in-browser support is no longer common, and Flash itself will be unsupported soon.

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Wowza powers scalable, reliable video for businesses looking to transform their product offering. https://www.wowza.com/