XF400 HDMI internal priority vs external only

[NickMDal]

Hi.  I have been outputting 4k 60 fps to an HDMI recorder.  Now I have an SD card that can record XF-AVC.  When internal priority is set to record XF-AVC, is the output to HDMI identical to the HDMI output when recording "external only?"

I ask because XF-AVC is compressed and I am guessing HDMI "only" is uncompressed (though not raw).  So does the camera output two different formats at once (compressed to SD and uncompressed to HDMI) if internal priority is set and a recorder is connected to the HDMI?

[NickMDal]

Okay I'll take a guess and maybe someone will correct me.

The HDMI output is always the same regardless of recording priority set. So... it is possible to have XF-AVC and Apple ProRes (via recorder) from the same footage.

The HDMI sourced ProRes quality is identical whether or not the camera is also writing XF-AVC to an SD card at the same time.

[Tim]

Hello NickMDal, 

I believe the chart on page 105 of the XF405 manual references the various methods to set up the video output using the internal/ external recording.  

Link here. 

[NickMDal]

Thank you for answering. Yes I have the manual. It doesn't really address my question. It was..

"So does the camera output two different formats at once (compressed to SD and uncompressed to HDMI) if internal priority is set and a recorder is connected to the HDMI?"

in other words, is the output to HDMI identical whether or not the camera is simultaneously recording to SD in a compressed format?

[Tim · Accepted solution]

Hello NickMDal, 

We spoke to our support engineering team regarding your issue and here is a summarization of their reply. They do firstly mention to reference the chart prior discussed, as this is there the information is drawn from. For your situation where you are looking to shoot in 4K at 60P, the HDMI output will be either 3840x2160 YCbCr 4:2:2 8 bit or 1920x1080 YCbCr 4:2:2 8 bit, depending on the capability of the connected monitor or recorder. 

When an HDMI device is connected to another HDMI device, a handshake will take place to determine what the maximum supported signal quality will be. So if it's an actual UHD recorder or 4K TV, then it will output 3840x2160 YCbCr 4:2:2 8 bit. However, if it's connected to a 1080p HDTV or monitor or recorder, then the signal will be established as 1920x1080 YCbCr 4:2:2 8 bit. This will have NO bearing on the internally recorded footage, just the HDMI output signal. 

[NickMDal]

Thank you for looking into this.  So simultaneous recording to the SD card does not impact the HDMI output quality.  i.e. I can record 4k 30fps 4:2:2 8 bit both to the SD card and an HDMI connected recorder that supports it.

In this scenario, the camera records XF-AVC to the SD (if I choose that option) and an unknown (compressed?) format (not RAW) to the HDMI.

Am feeling the answer about the compression type (if any) to the HDMI output is not forthcoming.  This was very helpful though so thank you!