14 Replies Latest reply on Dec 7, 2011 7:30 AM by Nash_John

    Video editing

    mid centry modern

      Are edits permanete after rending ? After I blur out a face for security....no one can reverse it and see the face later can they?

        • 1. Re: Video editing
          Steve Grisetti Adobe Community Professional

          The nature of non-linear editing is that the original video and audio files are unchanged, no matter what effects you add to your project.


          Even when you output your finished video, the original media files are left unchanged. (Technically, it's referred to as a "non-destructive" process.)

          1 person found this helpful
          • 2. Re: Video editing
            mid centry modern Level 1

            Okay, but the rendered, saved and exported file changes are not reversible correct?  I understand that you maintain the original file.

            • 3. Re: Video editing
              nealeh Level 5

              What technology creates, technology can reverse. In the UK a few years back there was some serious paedophile footage recovered by the police from a computer where the abuser had distorted his face with a blurred swirl effect. The police were able to reverse the effect and the sick s*d was caught and convicted - together with many others.


              • 4. Re: Video editing
                mid centry modern Level 1

                Ooohh, that’s what I needed to know, thanks so much, it is for a government project and I need to know so that the legalities are in place.

                • 5. Re: Video editing
                  Ted Smith Level 3

                  If you apply a disguise effect that destroys the bandwidth to the point where no transitions are there any more, there is no way for any technology to recover them.


                  For example nothing can recover a face that has had a blank white disk placed over the top of it to completely remove any face detail.


                  The same can be said for effects that create a chequer board of blocks of various shades by vastly reducing the bit rate in the area of the face.

                  If the bits for the eyes aren't there, nothing can recover them.


                  The final release DVD will not contain the original bits therefore it is secure.


                  I laugh at some attempts to disguise voices by slowing down the pitch. It is a simple matter to recover the original voice with something like Soundforge.

                  The only way to disguise a voice is by using a Voice to Text program then Text to synthesised Voice.

                  • 6. Re: Video editing
                    mid centry modern Level 1

                    Sorry, I’m new to this, so how is destroying the bandwidth different than applying an effect like a mosaic to cover the face. Better yet how to reduce the bit rate in that area alone.

                    • 7. Re: Video editing
                      the_wine_snob Level 9

                      I cannot address the bandwidth question, but when pixels have been re-arranged, they are pretty much permanent - however with that said, there are algorithms, that do a good job of "guessing" at what Effect has been employed, and then go about "reverse engineering" that Effect. They are similar to the algorithms used to reduce things like camera shake, or out-of-focus footage/images, or the removal of video "noise" from underexposure. The difference is that the forensic programs are going much deeper, and their algorithms are much more powerful. The forensic programs are not commonly available to the general public, and are highly sophisticated, plus expensive. How successful any will be might also be heavily reliant on the skill of the operator and on how important, the image recovery is - time is $.


                      To get even better "identity hiding," it might be useful to instead of applying any Effect, one were just to replace the pixels of the face with say a Shape, that is Filled with color, even just a white, or gray Filled circle, over the face. Then, in the Exported/Shared footage, there are NO remaining pixels to "reverse engineer," just white pixels, where the face once was. It will not look as "Hollywood," as a Blur, or Mosaic, but will be much tougher to "crack," as there are now no pixels from that face.


                      Good luck,



                      • 8. Re: Video editing
                        mid centry modern Level 1

                        I think I get it now, so replacing the face with a shape is no problem for appearance for my purposes that’s great…the main thing was to keep anyone from ‘unmasking’ the image and I think you have all given me the answer to that question.  I’ll leave it up to the lawyers to decide how secure they think it is.  Thank you all for your expert advice.

                        • 9. Re: Video editing
                          the_wine_snob Level 9

                          Yes, the lawyers can sort it out. Giving a forensics expert, equiped with the state of the art tools, little or nothing to work with, should go a long way to keeping identities "secure."


                          Good luck,



                          • 10. Re: Video editing
                            Ted Smith Level 3

                            The only way the original could be reconstructed is if enough pixels are left to reconstruct the original.

                            If the effect merely shifts the pixels or bits to another pattern then thius pattern can be reversed.

                            If the effect say removes every second pixel to blurr it, experts can guess where the missing ones were and reconstruct it

                            If you remove say 9 out of 10 bits or pixels to make it very blurry, any fine detail will be lost (such as a pimple on a face or the colour of eyes) but you still might be able to legally recognise the person by outlines to add to other circumstantial evidence.That is what I meant by bandwith limitation.


                            But if the bits are completely removed (such as a blank circle over a face) there is no way of reconstituting them


                            Don't forget criminals are often described in news flashes also by what they are wearing!

                            • 11. Re: Video editing
                              Ted Smith Level 3

                              An even tricker thing that is often done is to replace the blurred face with the blurred face of a competely different person (such as a dead film star or chimpanzee) that couldn't possible be the person concerned!

                              • 12. Re: Video editing
                                mid centry modern Level 1

                                “But if the bits are completely removed (such as a blank circle over a face) there is no way of reconstituting them”


                                Is putting a blank circle over the face, as you mentioned, the same as adding a shape (circle)? …this sounds like the perfect solution to me along with track matting.

                                • 13. Re: Video editing
                                  the_wine_snob Level 9

                                  The Shape of choice can be a square, rectangle, circle or polygon. The choice is yours, and the effect will be the same. You do not need Stroke the Shape, and a simple Fill will work fine.


                                  Good luck,



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                                  • 14. Re: Video editing
                                    Nash_John Level 3

                                    If the face you want to hide out, has got small and slow motions only, you can use object tracking feature of Premiere Elements, and place any clip art over the tracked face,then export it, it will hide out completely as the original pixels will be no more in the output.

                                    1 person found this helpful