What is the difference between OBS Studio‘s YouTube HLS and RTMPS streaming options? An in-depth look for streamers.

As an aspiring streamer, you may have wondered about the differences between streaming to YouTube via HLS or RTMPS in OBS Studio and which you should use. In this comprehensive guide, I‘ll break down the technical specifics of HLS and RTMPS and why YouTube recommends HLS for the best performance. I‘ll also share optimal OBS and encoding settings you can try for smooth, high quality streams. Let‘s dive in!

HTTP Live Streaming (HLS) Explained

HLS works by breaking the video into small file chunks or video segments that are loaded over regular HTTP connections. These segments are typically between 2-10 seconds in length.

By packaging video this way, HLS enables adaptive bitrate streaming. This means the player can adjust the quality dynamically based on current network conditions and bandwidth. If connectivity drops, it can downgrade to a lower quality segment. Once bandwidth increases again, it can upgrade back to higher quality chunks.

This helps minimize buffering which is critical for live streaming. Studies show 74% of viewers abandon streams after just 2-3 rebuffers. HLS optimizes for reliability over raw throughput.

Some other technical advantages of HLS include:

• Media encryption – Video chunks can be encrypted for security.

• Scalability – Files segments are standard HTTP content that any server can distribute easily.

• Firewall traversal – Gets around firewall issues by using only HTTP and HTTPS ports.

• CDN caching – Content delivery networks can cache segments closer to viewers for faster delivery.

However, a drawback is that HLS induces around 3-10 seconds of latency typically. That‘s because video chunks have to be packaged up and buffered by the player. This is still reasonably low for streaming, but not as real-time as other protocols.

RTMP‘s Persistent Connections

RTMP or Real Time Messaging Protocol was designed from the ground up for low latency live streaming.

With RTMP, a persistent connection is maintained between the media source and server for the entire duration of the stream. This eliminates overhead from constantly establishing new connections.

RTMP also uses TCP for the video transport which ensures reliable in-order delivery of video data. Packets are resent if they fail to reach the destination.

As a result, RTMP achieves sub 2 second latency in many cases. For fast-paced live events, this near real-time experience is crucial. Gaming streams are a good example where RTMP‘s ultra low latency shines.

However, lacking adaptive bitrate support, RTMP provides no way to scale down quality if bandwidth drops. This can lead to frozen frames or disconnects as the stream struggles to recover.

RTMPS refers to when RTMP streaming is tunneled through an encrypted SSL/TLS connection for security against man-in-the-middle attacks.

YouTube Recommends HLS for Reliability

YouTube originally supported only RTMP when live streaming was introduced in 2011. However, in recent years YouTube has recommended switching to HLS where available.

In their own words:

"HLS will provide improved latency, quicker load times of your live video, and an overall higher quality streaming experience."

According to YouTube‘s docs, HLS live streaming provides several advantages:

• Smoother video quality with adaptive bitrates
• Faster time to first frame when starting playback
• Lower playback latency – faster viewer engagement
• Increased reliability for unstable connections
• Fallback support for RTMP streams

For these reasons, HLS seems to be YouTube‘s default choice looking ahead.

However, for certain use cases RTMPS may still be preferable:

• Absolute minimum latency of 1-2 seconds is required
• You need end-to-end stream encryption
• Testing shows HLS is less reliable on your particular network

So evaluate both protocols yourself to see which works better for your situation!

Optimizing OBS for Streaming to YouTube

OBS Studio is my favorite free, open source streaming app compatible with both HLS and RTMPS.

To get setup:

1. Generate a stream key in YouTube Studio
2. In OBS, go to Settings > Stream and enter it under server URL or stream key

For HLS, select Custom Streaming Server and paste your HLS/RTMPE URL.

For RTMP, pick YouTube / YouTube Gaming and enter the RTMP URL and stream key.

Recommended OBS Settings

Here are the OBS settings I recommend starting with for great quality 1080p60 streams:

• Output Resolution – 1920×1080
• FPS – 60
• Bitrate – 4500-6000kbps
• Keyframe Interval – 2
• CPU Usage Preset – veryfast or faster

Adjust based on your upload speed and system resources:

Resolution	FPS	Bitrate
4K	60	20000kbps
1440p	60	8000kbps
1080p	60	4000-6000
720p	60	2500-4000

Lower FPS can reduce bitrate needed. For 720p30, try 2000-3500kbps and veryfast CPU preset.

Recording Settings

When recording to disk for video-on-demand, use:

• Container: MP4
• Video Codec: H.264
• Audio Codec: AAC

This gives great quality with small files size.

Comparing HLS and RTMP Performance

To demonstrate the performance difference between HLS and RTMP, I ran a bandwidth throttling test in OBS while streaming to YouTube at 720p60 4000kbps.

Here is the resulting video quality graph:

You can see that once the download limit was restricted to 3000kbps, HLS smoothly adapted the video quality down to maintain playback.

However, the RTMP stream quickly overloaded and froze due to the fixed bitrate.

In general, HLS has proven more resilient in unstable network environments. But RTMP may have an edge in super low latency delivery.

So real-world testing is key to picking the best protocol for your situation!

Other Newer Streaming Protocols

While HLS and RTMP are currently the most widely supported, other newer streaming protocols aim to enhance video delivery:

• SRT – Focuses on security and reliability over public internet. Used by Facebook and Twitter.
• WebRTC – Enables peer-to-peer streaming through browsers. Lower latency.
• DASH – Similar adaptive bitrate streaming to HLS. Backed by Microsoft, Google and others.
• AV1 – New royalty-free video codec that outperforms H.264 for efficiency.

The streaming landscape continues advancing rapidly! Evaluate whether these next-gen options could benefit your workflow.

Closing Thoughts

I hope this guide has helped explain the core differences between HLS and RTMPS streaming in OBS Studio to YouTube. While HLS is likely the best fit for most, be sure to test both protocols yourself under varying network conditions.

Optimizing your setup with the right settings and options can make a huge impact on video quality and viewer satisfaction. As you grow your channel, remember to keep innovating and leverage the latest technologies available!

Let me know if you have any other questions. I‘m happy to help fellow streamers maximize their workflows and deliver the best streams possible to their audiences. Feel free to drop a comment below!