The place to discuss Faceswap and Deepfakes
https://forum.faceswap.dev/
While extract , it is mentioned that cv2-dnn is CPU only while Sf3d is recommended.
Does it mean we should not use cv2-dnn at all ? It seems fast. So, Does it mean the quality or alignments will be of inferior quality?
Is the only difference between these detectors/aligners are about finding a face or is there output quality aspects involved ?
There are differences between the different detectors and aligners, and in general CV2-DNN is the worst of the options for quality, but by all means use the one that you like the most. The alignments shouldn't be "worse" (and we do accomodate them to some degree anyway with random skewing) it just might mean that some faces are missed or have to be removed when you're cleaning your data that the other detectors or aligners might have handled better.
If you're very short on data you may want to actually run multiple extracts using each one once, but otherwise just use the one you want.
------------- Did a bit of research myself by extracting and converting with all the 3 detectors. HERE are my findings:
Cv2-Dnn - Gave me lesser number of faces. As admin mentioned, we need to run multiple passes. However, sequence of images is not guaranteed. It still missed a lot of faces. On conversion, edges were blurry
MtCnn - gave slightly better results than the first. However, there are still missed faces. Edges were fine in this but flickering came. I guess its because of missed frames
Sf3d - the bid daddy. Had to wait some time before seeing the result. But flawless detector. More faces. Better conversion. Crisp finishing.