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Streaming and Recording - Different Bit rates

PostPosted: Mon Jun 29, 2020 4:53 pm
by filmmason
I am wanting to setup a solution for live switching and streaming of an event (likely in 4-8Mbps bit rate) but would also need a high quality recording in 422 ProRes for Broadcast. What would be the recommended product mix to achieve this? We plan to use a mix of BMPCC4K cameras and if possible some Nikon Z6.

I assume a round-about solution would be using an ATEM Mini Pro for streaming and then recording to the in-camera SD cards the ProRes on the BMPCC4K - and then manually editing each camera stream later. If we use a Z6, i assume we would need to use a HDMI splitter to send images to ATEM Mini Pro and to an external ProRes recorder. Would that work? I assume we would also need in a sound mixer. Or is there a better workflow, that allows simultaneous recording of the live edited mix in two quality outputs - low res H264 and ProRes? Perhaps using ATEM Television Studio and a HyperDeck? Is that possible?


Re: Streaming and Recording - Different Bit rates

PostPosted: Mon Jun 29, 2020 6:07 pm
by stlplayersclub
I'm sure someone has a better answer than this - especially since you seem to be mostly hardware-driven, but I know in streaming software (OBS and Wirecast at least) you can stream in a different resolution than you record locally. I typically will stream at a pretty low bitrate for our mobile viewers (like 2500 bitrate) but I'll record the event locally at 25000 bitrate for editing/uploading later. Not sure about the ProRes as those cameras are not in my sandbox. I just use x264 for encoding both qualities as I'm not doing TV-type content - but I can change the encoder and settings for each.

However, if you have a lossless HDMI splitter, I don't see why splitting the raw signal wouldn't work. In fact, if you had a mixer for the audio in place and were able to incorporate that with the video switching, then take that single mix from the video switcher and split it - one to the Hyperdeck and the other to the broadcasting device (which will be downscaled) - wouldn't that work?

I don't know if the ATEM Mini Pro's ability to record to external HD is before or after the streaming encoding - but I know it can communicate with Hyperdecks on the same network. Again, that's outside of my sandbox, unfortunately.

Re: Streaming and Recording - Different Bit rates

PostPosted: Tue Jun 30, 2020 1:57 pm
by filmmason
Thanks for the reply. I haven't used OBS so i will look into it. Perhaps OBS could simultaneously record high bit rate ProRes and low res h264.

Re: Streaming and Recording - Different Bit rates

PostPosted: Tue Jun 30, 2020 3:12 pm
by stlplayersclub
OBS can not record 2 different stream qualities ... but it can record something different than it broadcasts. Wirecast can do this also. I don't know of any software that would allow 2 different recording qualities. Mostly because I think the common scenario is to record at max quality and if you need to downscale it for something that can be done when it's needed.

As for ProRes, that exact format, is not something OBS can record (I dont think). It can do things like mkv, flv, mp4, ts, and m3u8 (according to my install anyway). There is an option for custom Muxer settings where you can likely record to avi or perhaps something else, but I've never played with that.

Just didn't want to give you any potentially bad info about OBS.

Re: Streaming and Recording - Different Bit rates

PostPosted: Wed Jul 01, 2020 12:16 am
by Dave Del Vecchio
OBS can record to ProRes if using custom FFMPEG encoding settings. There's a video tutorial for this here: