Screen Capture from Source and Screenshot Output Results in large File Size

[OBSx021]

Linux Mint 20.1 (64 bit OS)
DesktopPC
TV/Monitor: 4K Monitor ( 60.00 Hz Vsync recommended setting)
device source for screen captured content: Raspberry Pi 4 2b (Lakka OS, Emulator Frontend)
Note* I dont do streams, so I dont care about streaming
*Logs and Image attached.

I noticed that when I switched the Video Format from YUYV the screenshots ended up being much bigger in file size (Im not talking about resolution) and the the difference is huge from 177 Kbs to 1.8 Mbs file size. Is this a bug that's causing the file size to bloat that big? While I can switch back it ends up making the frame-rates down to really low around 5 FPS making games difficult to play,
Any workarounds for this in the mean time?

I have tried the other 3 but they still end up being noticeably big and BGR3 looks a bit off in color and still too big around 1.5 Mbs, I do use the screenshots for thumbnails for my Custom Emulator theme like the one in the attachment.

 

[OBSx021]

I would like to add that lowering the frame rate for the Video Capture Device V4l2 properties resulted in smaller file sizes on the screenshots the lower you went. While going to a higher frame rate resulted in a bigger file size. Does anyone get why it does that as well?

 

[Tuna]

So are we talking v4l2 source and "emulated" formats? Internally the transmission over the USB bus will be in jpeg, or other compressed formats. These formats are lossy formats eventually causing artifacts. These can lead to the difference in size when you compress them. (As the signal is now more complex than the original due to compression artifacts)

 

[OBSx021]

From my Sources the Video Capture Device (V4L2) is the name given to my video capture card when I added it. While I had it on YV12 (Emulated) for the Video format, that setting along with the others besides YUYV12 4:2: tends to result in large file sizes for my screen shots. It has something to do with the Frame Rate, because When I set the " Frame Rate" down to 5, the screenshot size is small, but when Its set to 60 it results in big bloated screenshots (.png files).


If it makes any sense. I dont leave it on YUV12 4:2:2 because It's low 5 "Frame Rate" makes it difficult to play a game. But currently it seems if I want to keep the file size down when taking source screenshots at the moment is to switch it to that YUV12 Video Format.