10 Replies Latest reply on Jan 28, 2013 12:12 PM by alexdejesus

    Roto Brush Will Not Hold One Frame to Next

    alexdejesus Level 1

      Roto Good.jpgRoto NG 1.jpg

      What am I missing? Roto brush tool does an awesome job with the initial mask, but a few frames down the line a patch above the head appears. I brush it out, but it reappears on the next frame. The rest of the mask is perfect and holds all the way through, but that one spot will not go away. It seems I have to paint in every frame, which isn't too bad, but doesn't seem right. I tried different brush sizes, refine mat, smoothing, and different Edge Detection settings but no help. Clip is 10 seconds long H264 in CS6 Windows

       

      I can eliiminate most of that area, but sometimes nothing happens when I paint a stroke. I am holding the Alt key

        • 1. Re: Roto Brush Will Not Hold One Frame to Next
          Mylenium Most Valuable Participant

          Hard to tell from your screenshot, but it seems you are working against the effects smartness by adding too many base frames. This happens when you don't let it propagate and place paint strokes too closely together in time. Let it finish the analysis and extend the propagation region by pulling out the bar left and right, then only refine the areas it doesn't get right with the automated detection.

           

          Mylenium

          • 2. Re: Roto Brush Will Not Hold One Frame to Next
            alexdejesus Level 1

            Roto Pre.jpg

             

            Mylenium wrote:

             

            Hard to tell from your screenshot, but it seems you are working against the effects smartness by adding too many base frames. This happens when you don't let it propagate and place paint strokes too closely together in time. Let it finish the analysis and extend the propagation region by pulling out the bar left and right, then only refine the areas it doesn't get right with the automated detection.

             

            Mylenium

             

             

            I may settle for removing just the blue banner, but I'd like to get rid of the black background as well. I will start again from scratch.

            It took about 20 strokes to roto the first frame. Is that too many?

             

            What do you mean "too closely together in time"?

             

            Should I use the Edge Detection 'Favor Predicted Edges' or 'Current edges'? The default is 'Balanced'

             

            I just found a tutorial video

            • 3. Re: Roto Brush Will Not Hold One Frame to Next
              Dave LaRonde Level 6

              " just found a tutorial video"

               

               

              There should be more than one, and they will help a lot, I think.  Rotobrush isn't the most intuitive tool on the planet, and a little push in the right direction helps.

               

              And 20 strokes is A LOT!

              • 5. Re: Roto Brush Will Not Hold One Frame to Next
                alexdejesus Level 1

                Dave LaRonde wrote:

                 

                " just found a tutorial video"

                 

                 

                And 20 strokes is A LOT!

                I'm going through Chris Meyer's Lynda.com "Paint, Roto, and Puppet" and he emphasized getting the first base frame pretty well before moving on to propagation. He made a lot more than 20 strokes, even making pixel level strokes. I can see less than twenty if I'm just eliminating the blue banner, but I'm actually doing the whole body.

                 

                Anyway, I started from scratch and it's starting to make sense. Get the base frame right, and then propagate a stroke or two to make corrections. Meyer did stress that there is no 'automatic' function and that you can count on eventually stopping at every frame. As he says. Instead, there should be fewer corrections as you work away from the base frame in both directions.  And make a new base frame when the effect is no longer propagating well.

                 

                So, for a 10-second clip, that's a heck of a lot of work and time. Mylenium seems to be saying that once you do the base frame, that you can just let it roll on its own through the clip and then go back and make corrections, which conflicts with the tutorial. Maybe I misinterpreted?

                • 6. Re: Roto Brush Will Not Hold One Frame to Next
                  Dave LaRonde Level 6

                  I think you may have misinterpreted Mylenium's meaning.  The demands of a particular shot determine the job at hand.  To do rotoscoping well is a time-consuming, painstaking, detail-oriented task. 

                   

                  Rotobrush makes the task easier, but it doesn't make it automatic. 

                  • 7. Re: Roto Brush Will Not Hold One Frame to Next
                    Todd_Kopriva Level 8

                    There's no conflict between what Mylenium and the Meyers' tutorial said; it's just a matter of degree. Depending on the shot and how precise you need the edge to be, things will be more or less automatic.

                     

                    > So, for a 10-second clip, that's a heck of a lot of work and time.

                     

                    It's probably a lot less work and time than doing it the old way, manually changning the shape of several masks on each frame.

                    • 8. Re: Roto Brush Will Not Hold One Frame to Next
                      alexdejesus Level 1

                      I did misinterpret because I had to read his post a dozen times before it started to sink in. it is a matter of degree. The clip in the tutorial is a lot more detailed than mine, I think.

                       

                      Meyer said that once you make corrective strokes away from the base frame, that it it not good to go back towards the base. That makes sense. But he also said that you can back track to change other non-stroke settings, Like threshold, etc. Do I have that right?

                      • 9. Re: Roto Brush Will Not Hold One Frame to Next
                        Dave LaRonde Level 6

                        Yes, you have that right, but I think you and I approach rotoscoping from different viewpoints.

                         

                        For me, roto work represents one of the most dreadful jobs imaginable in AE.  I avoid it as much as possible.  I get the notion that you feel it's no big deal, and they should have figured this stuff out by now for the benefit of the users. 

                         

                        I expect the truth is some place in between.  So I'm listening & learning here.

                        • 10. Re: Roto Brush Will Not Hold One Frame to Next
                          alexdejesus Level 1

                          Oh no, I know that it is a big deal, but this rotobrush tool is amazing in what it can do compared to the old school way. Even if you have to hit every frame, at least you don't have to redraw the entire mask each time. Whether it's worth doing or not depends on how nicely it turns out.

                           

                          As frustrated as I get sometimes, I always get answers when I hit the forums about Premiere or AE or Photoshop. Now, an app like Speedgrade is totally not worth messing with at this point.