Software for Lossless Capture of HD Video and 5.1 Audio

I'm trying to capture 720p-1080p60 video + 5.1 audio coming out of a DVR via HDMI. All of the Blackmagic and DeckLink models "support 8 channel HDMI audio". Using an HDMI audio injector, I could insert the 6 channels of 5.1 audio, BUT I cannot find any capture software that will LOSSLESSLY capture the video AND 5.1 sound. When using a Magewell capture card (which also supports 8ch HDMI audio) with OBS or Virtual Dub and lossless codecs, only 2 of the 6 channels are allowed through by the SOFTWARE to be recorded, even though the card itself passes all 6 ch through to the software. Does anyone know of any AV capture software that will losslessly record both HD video AND 5.1 audio from an HDMI input when using Blackmagic or DeckLink capture cards?

Has anyone here tried losslessly capturing HDMI video + 5.1 audio using any of the Blackmagic or DeckLink capture cards?

What kind of DVR are we talking here about?? I guess your not talking about security DVR's so it should be a Set top box DVR?? Realise that those DVR's have HDCP which will prevent you from even getting video with a decklink card or any other broadcast piece of hardware...

Yes, it's a set top box DVR, but let's just say that HDCP is a non-issue.

Well if HDCP is a non issue than please talk to the guy in the Live forum.. He has a lot of HDCP issues..

OK, checking to see if my particular device is still available and works on a Mac.

In the mean time, has anyone here been able to record uncompressed video + a Dolby Digital AC3 stream via HDMI on any of the low-end or high-end Blackmagic or DeckLink capture cards?

Hi here I also have a Magewell Pro Capture HDMI.

Using an HDMI audio injector, I could insert the 6 channels of 5.1 audio,

Could you tell me the exact name of this injector to watch it online.
Could you hear multichannel with the Magewell card with this Audio injector? (all 6 channels on, e.g. viewed with lavaudio filter)

though the card itself passes all 6 ch through to the software.

Thanks
Michael