I've been recording PS3 through HDMI since like 2012 I think, so I have some experience working with this type of stuff.
Nowadays, most people use an HDMI splitter. However, just make sure the splitter you are purchasing will actually strip the HDCP, and make sure it's not a super cheap build. I bought a splitter online that some people were recommending, but it only worked for a few months before it just stopped. It's easy to find cheaply built splitters that strip HDCP, because that is not an intended effect of most splitters.
The method that's been working for me since 2012 is using a DVI + Optical Digital to HDMI converter. There's some pros and cons to this method. One pro is that these aren't built super cheaply, so you will more than likely be buying a quality product that will work. Mine has been working since 2012 without any issues. That's because these strip HDCP a little differently; DVI is the same quality as HDMI, but it just drops the HDCP since it's not compatible with it. One con though is that you probably will be paying a bit more, and for a bit more equipment. DVI is basically HDMI video without the audio, so you will need to make sure to have a HDMI to DVI cable and an optical digital cable, as these will be combined into one HDMI output in the converter box. Another con is that if you try to record something without an optical digital port, like the PS TV, you will not be able to record the audio.
Hopefully that is somewhat informative. I'd probably recommend the splitter method, because you will be able to record the PS TV if you want to. If that isn't a concern to you, you can buy whichever option. I think the splitter would be better and it's the more popular method, so obviously it works for many people. Just make sure to get a decent quality splitter that will split the connection, since I did not and mine broke.