Question / Help Apple Hardware Encoder destroys stream

[Hollywood Rose]

Hi.

I have been streaming with the x264 encoder on my Late 2014 Macbook Pro that has a GeForce card in it. I had streamed before with the Apple Hardware encoder but so often the stream will completely screech to a halt and show in the red and like 300bps or something and just literally I get disconnected from Twitch.

Performance is amazing but it's unstable as hell. This was a couple versions ago in OBS. I'm now using the latest version.

I was doing fine with x264 but now I've added a Mackie ProFX16 and run all my sound through there and also use a 2x2 audio interface for notifications.. It runs fine when the FPS is set to 30, but if I set the FPS to 60 the stream is choppy as hell.

I think with the hardware encoder it would be much much better but don't understand why it messes up like that.

Is this a known issue or anyone know how to fix it? I saw something somewhere about setting keyframes to 2. I already did this as it's in Twitch's recommended broadcast settings.

 

[eliasthompson]

I experimented streaming with the hardware encoder for a while on my MacBook as well. I ran into similar recurring issues. I believe the main issue is that Twitch really needs a constant bit rate (CBR) to maintain a stable stream, which only the x264 encoder provides.

 

[RytoEX]

A while back, I'd suspected that streaming issues with the Apple Hardware encoder were actually a deeply buried and complex issue involving some old changes to the underlying RTMP code, but I couldn't prove it. More on that in this thread. If you're interested in running some tests, PM me, and I'll try to prod someone to get a couple test builds to test that theory.

 

[Hollywood Rose]

The interesting thing about that is that I have watched podcasts with streamers who say they stream at VBR because it's WAAAY more efficient for them and also something about H.264 being optimized for VBR and the CBR being kind of a "hack" ... and it works fine despite Twitch recommending VBR.

Or are you saying that the hardware encoder doesn't provide a stable "CBR" ?

This is what kinda worries me about using a Mac for streaming though, as on Windows I've used NVEnc with zero problems, but on Mac it's a no go.. and I plan to get an iMac Pro to support all the stuff I want to do with my machine. It would be SUPER ideal to be able to have the Radeon Pro Vega do the encoding but unfortunately I just don't think this will be possible.. The 8-core Xeon would still beat the hell out of the MacBook Pro i7 I'm using now, but still ... it's kinda like a waste of CPU when the GPU power is waaaay more than adequate for the job.