We used to do this in the past but it's become increasingly hard to use cutscenes to judge a games graphics.
What is a realtime cutscene to you? Realtime means that it's being rendered by the hardware in real time. It is not a video, not cgi rendered like those old PS1 cutscenes.
Does that mean that it's an accurate representation of the ingame (gameplay) graphics? No.
There are many reasons to be skeptical of cutscene visuals. For a start, some cutscenes you assume are real time actually aren't, with HD video being swapped in. Usually the way to tell if they are really realtime is to change a costume for the main character and see if it is represented in the cutscenes from then on.
But even realtime cutscenes aren't an accurate representation of the ingame (gameplay) graphics. Many games take advantage of the fixed and focused perspective nature of cutscenes to change the rules of the game if you will. They swap out lower poly models for higher ones. The next time you watch a cutscene, pay attention to the character models face, then in gameplay zoom the camera right in and see the difference. I recentely did this with Assasins Creed 3 and I have done it with Arkham City and other games in the past too. There is a big difference between them.
They also sometimes change thelighting or anti-aliasing algorithm too, using a method that cannot be used in gameplay because it comes at too high of a hardware power cost. And they can prioritise and custom make better looking textures than they can acheive in game across a whole level.
The fixed nature of a cutscenes means they can choose where to focus the camera and not render what is not being seen. In gameplay the whole level has to be rendered and visible when someone turns the camera around. In a cutscene they can frame a small portion of an environment, even use depth of field to blur backgrounds and pump detail into character models and foreground environments.
So the next time you see an amazing cutscene, just check to see if the gameplay matches up to it. Also think about this, with all the new systems having Bluray they can just put the cutscens on as HD video and you wouldn't notice the difference. So those amazing Agni Philosyphy cutscenes, you could dump them as HD video on one platform and revert to lesser graphics in gameplay. Whilst on a more powerful platform you could seamlessly swap between gameplay and realtime.With HD video there might be a fade to dark and a seconds' delay.
That last bit reminded me about the change in character model quality between cutscenes and gameplay in FFXIII.
"We used to do this in the past but it's become increasingly hard to use cutscenes to judge a games graphics."
When the hell did we do this?
Ok.
Another odd thing that I noticed is Connor's character model looked downright odd at times during the cutscenes. He would have a different shade of color on the front and pitch black on the back of his head, like we weren't supposed to see the back because his hood should've covered it.
Also some games use the actual game character models for the cutscenes or something which looks similar enough to fool you. Even though they are on song with the in game models for accuracy they do have subtle improvements.
RE5 had obviously improved cutscenes compared to in game but because the art and models were so similar it wasn't hugely jarring.