Multi Plattform Aspect Ratio Support / Crop Stream and Record Full Video

letsbash

New Member
// TLDR below

Hello all,
first of all I want to thank you all for OBS - I love this tool!

When I last bought a PC, I treated myself to a beautiful samsung 49" monitor with a 32:9 aspect ratio, on which I've been producing gaming content for quite some time.

Since I found out that YouTube also supports other aspect ratios (e.g. 21:9 or 32:9) besides the normal 16:9 format, I started to create more branded channels for different resolutions and aspect ratios (feel free to check them out on Letsbash.de).

Primarily I'm active on Twitch a lot and use the YouTube brand channels mainly as a high quality streaming archive. For stream management I use the Stream Deck from Elgato.

But a while ago I decided to abandon the branded channels for 32:9 and 21:9, because the effort to create this content is incredibly computationally intensive and sometimes unreliable.

Let me explain how I solved it:
1. OBS recording in 32:9 format to an SSD hard drive with 80,000kbps CBR MKV (NVIDIA GPU offload).
2. Read the recording while creating it with FFMPEG, convert the aspect ratio to 16:9 (-vf crop) and stream to Twitch (INTEL GPU offload)
3. After streaming: convert the OBS recording with FFPG to 16:9 and 21:9 (-vf crop)
4. Upload all recordings to YouTube

So in principle I just recorded with OBS and converted the recording again with FFMPEG. In my experience, the OBS recording must always be created with an incredible quality, because otherwise the FFMPEG conversions of game content quickly show mosaics and compression artifacts on Twitch and YouTube. This means that the SSD runs an extremely large number of write operations.

Unfortunately, this setup doesn't allow me to start or stop recording and streaming independently of each other via the Elgato Streamdeck, so I also have the stream start and stream pauses on YouTube.

But the biggest problem with the setup is the latency to the stream on Twitch and the unpredictable abort of the FFMPEG process when the end of the recording being written by OBS is reached. FFMPEG processes the frames minimally faster than they are written and can come to a point where there is no more data and aborts the process and the associated stream accordingly. I wrote a program which then intervenes and restarts FFMPEG and jumps with a fast forward to the last known time index. But this doesn't work really well and adds extra latency to the stream, so interaction with viewers is very problematic. I had about 4 minutes of latency at peak times.

I've seen other streamers on Twitch and YouTube have similar problems with ultra-wide monitors. Ultra-Wide monitors are no longer a rarity.


// TLDR starts here

Therefore I ask very dear for a feature for streams:
It would help me incredibly if in the options menu -> Output -> Stream next to the item "Rescale output" also an item "Crop output" could be added. So for example my recording is 3840x1080 and my stream is cropped to 1920x1080 (from width 960px to 2880px - center of screen). This would solve both the stability and the latency problem immediately.

Would love to hear from you,

Bashy
 

letsbash

New Member
I forgot to mention that Streamlabs has some kind of solution for the problem with the Selective Recording feature. Basically you need to set the resolution to 3840x1080 (original resolution), scale the streaming resolution to 1920x1080 and place the source "Game recording" 2x on the scene. The first game recording is normally 3840x1080 over the whole area and is only displayed when recording. The second game recording is only displayed when streaming and is centered and pinned to the 3840x1080 area at a transformed and streched resolution of 7680x1080. By scaling it to 1920x1080 when streaming, the result is achieved. Of course, the scaling has to be at least bicubic.

The bad news: My Nvidia RTX 2080TI is already at a load of 50% in an empty scene and there is hardly anything left for demanding games. I first tried to play GTFO with it... there were practically neither for the stream nor for the game enough resources available.
 
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