27 Replies Latest reply on Feb 7, 2010 7:57 AM by Harm Millaard

    Deinterlacing Question

    Blue_Devil1 Level 2

      I captured some footage  as SD 60i and I wanted to create a web movie with it. I'm using Prem Pro CS3.

      Since it was for Vimeo and they seemed to want H.264, I used Adobe Media Encoder for output.

      I selected H.264, square pixels, Progressive which I thought would avoid interlacing artifacts (combing).

      However, when I viewed this in both the source and output screens one particular area of high motion (flames) both showed combing.

       

      I thought that progressive was supposed to remove this artifact.

       

      However, if I went to the original clip and right clicked - Field OPtions and set to "always deinterlace", then when I looked at the source and output screens in AME, the combing was no longer present in either source or output screens

      .  Indeed, if I rendered the clip as H.264 Progressive with field options set to None, the combing was present and if I rendered H.264 Progressive with the field options set to Always Deinterlace, there was no combing.

       

      Does this mean that at least in CS3, H.264 Progressive isn't really Progressive?

       

      Or did I miss something in the help files about having to set the field dominance to always deinterlace AND  render out as progressive?

       

      Thanks for your help in advance.

      John Rich

        • 1. Re: Deinterlacing Question
          Jeff Bellune Adobe Community Professional

          There's a lot of subtle stuff going on here.

           

          Progressive H.264 export in CS3 goes back to your source footage and then looks at what the sequence is doing to it, if anything.  Since you haven't told Pr to deinterlace the footage, the AME constructs a full progressive frame out of the interlaced fields of the source.  That results in combing.

           

          When you tell Pr to deinterlace the footage before encoding it, either in-sequence or by using the Always Deinterlace check box, then Pr passes a deinterlaced progressive frame to the AME to be encoded as progressive H.264.  No combing.

           

          Bottom line: to get true progressive footage out of CS3, you have to explicitly tell Pr to deinterlace the footage.

           

          -Jeff

          • 2. Re: Deinterlacing Question
            Blue_Devil1 Level 2

            Jeff,

            Thanks a lot.  Great explanation. (I gave you an "answered" ).

             

            Apparently I've been encoding as "progressive " for years and not doing anything except compressing the size of the file.

             

             

            John

            • 3. Re: Deinterlacing Question
              Ann Bens Adobe Community Professional & MVP

              This is interesting.

              Does this apply to H264 only or to other formats like wmv which is by default progressive.

              • 4. Re: Deinterlacing Question
                Jeff Bellune Adobe Community Professional

                The behavior is independent of the codec or format.  Force deinterlacing and export progressive and you'll get the results you expect.  Export interlaced material as progressive without explicitly deinterlacing the source video, and you'll get unexpected results.

                 

                -Jeff

                • 5. Re: Deinterlacing Question
                  Ann Bens Adobe Community Professional & MVP

                  This is quite surprising because i have

                  rendered to wmv progressive for the web many times and never

                  seen combing.

                  • 6. Re: Deinterlacing Question
                    Jeff Bellune Adobe Community Professional

                    NB: This situation is "remedied" in CS4.  There is no "Always Deinterlace" check box in the export settings, and if you export interlaced material as progressive, CS4 is smart enough to do the deinterlacing for you automatically.  Select "Maximum Render Quality", and the deinterlacing will be much better than the deinterlacing in CS3.

                     

                    Again, the behavior in CS4 is independent of the format and codec chosen for export.

                     

                    -Jeff

                    • 7. Re: Deinterlacing Question
                      Jeff Bellune Adobe Community Professional

                      Ann Bens wrote:

                       

                      This is quite surprising because i have

                      rendered to wmv progressive for the web many times and never

                      seen combing.

                      That's why I called the results, "unexpected". 

                       

                      -Jeff

                       

                      EDIT: IIRC, even with H.264, not all of John's video exhibited combing.  The flames were just one (the only?) part that did.

                      • 8. Re: Deinterlacing Question
                        Ann Bens Adobe Community Professional & MVP

                        In that case i hope the results stay 'expected' because

                        setting Always Deinterlace to several Hundreds of clips is no fun.

                        • 9. Re: Deinterlacing Question
                          Ann Bens Adobe Community Professional & MVP

                          Yes that is what i was thinking of John video.

                          • 10. Re: Deinterlacing Question
                            Ann Bens Adobe Community Professional & MVP

                            The manual does not tell you all this stuff, thanks Jeff.

                            • 11. Re: Deinterlacing Question
                              Jeff Bellune Adobe Community Professional

                              You're welcome. 

                               

                              Manuals tend to describe how things are supposed to work, not why

                              things work that way.

                               

                              -Jeff

                              • 12. Re: Deinterlacing Question
                                Blue_Devil1 Level 2

                                Jeff,

                                Since you mentioned that CS3 makes a progressive frame out of two fields, perhaps if there is little change in the two fields over time (1/30th sec) then when the two non-delinterlaced fields are put together, it wouldn't be noticeable.  However, with rapidly moving or changing footage like flames, two slightly different fields would be put together, making the lines.  I assume that's what you had in mind when you originally told me to do just the flame part of the video.  Does that make sense?

                                 

                                I really appreciate your going through this, since it's sort of academic once Adobe fixed it and folks no longer use CS3 much but it's still great info..

                                In case you want to actually see the video   http://vimeo.com/8923241.

                                 

                                 

                                Ann,

                                For some reason, I've never been able to get  .wmv to look good, even when I made tutorials, and I was wondering if you would share your settings?

                                 

                                 

                                John

                                • 13. Re: Deinterlacing Question
                                  Jeff Bellune Adobe Community Professional

                                  Correct on all counts, John.

                                   

                                  -Jeff

                                  • 14. Re: Deinterlacing Question
                                    Ann Bens Adobe Community Professional & MVP

                                    Sorry John about all the confusion.

                                    CS3 does not quite behave as it should do, if just found out.

                                    I cannot give you settings because i do not have CS3 anymore on my machine.

                                    If CS3 cannot give you what you want i would consider the standalone Windows Media Encoder.

                                    But if you are realy capturing progressive with Cineform you ought not to have these issues.

                                    • 15. Re: Deinterlacing Question
                                      Blue_Devil1 Level 2

                                      Ann, I am trying to figure out some type of work flow for using captured AVCHD 1920x1080 60i for both regular DVD's (SD), and the web.

                                      Up until now, I was capturing with Cineform's HDLink and simultaneously converting the footage to Progressive.  Then editing and downsizing with Cineform and outputting with AME (CS3) to Mpeg2 for DVD and Mpeg4 for Vimeo.  In spite of being against the "conventional wisdom" of "always follow through  with your original footage settings", this seems to work well on my HDTV and PS3 I use for playing the DVD's and Vimeo.  Theoretically, no data is lost by deinterlacing.

                                      However, I was always careful not to pan rapidly or include any rapid action.

                                       

                                      From what Jeff said above, I assume that you don't lose any data if you just "create" a progressive video from an interlaced video unless you also deinterlace the video you are using to create progressive footage (ie I assume that deinterlacing discards one of the two fields per frame).  Again, from what Jeff said, if one has rapid action, then changing interlaced to progressive freezes the artifact causing slight movement between intra-field frames into each frame and there is no way to get rid of it then.

                                       

                                      Again, based on above, if I plan to video something where there is action, then I shouldn't convert to progressive but follow through with interlaced.  However, at the end with encoding to Mpeg4, it may be best to just deinterlace only the parts with the action to avoid artifact, before converting the footage to progressive so I would save the data in the relatively still areas of the footage (sort of crude Adaptive Deinterlacing).

                                       

                                      I realize this is all theoretical and it would be extra work to search out the action parts of the footage, but maybe I'll be able to work it out better in the future. Looks like I'm back to "conventional wisdom" .   Naturally, any comments from you and Jeff are always highly regarded.

                                       

                                      John

                                       

                                      ADD.  By the way, how do you output to the web with CS4?  Windows Media Encoder always has given me a lot of motion artifacts in the past.

                                      • 16. Re: Deinterlacing Question
                                        Ann Bens Adobe Community Professional & MVP

                                        Making it progressive or deinterlacing either way you are throwing a way have your vertical resolution.

                                        Now for the web its not that important but a dvd shows like its somewhat  'wooly'.

                                        BR does not alow progressive.

                                        Nowadays i only make wmvHD HDTV720 with max render quality

                                        Tried the H264: was not as good playwise. But i like YT better than Vimeo.

                                        • 17. Re: Deinterlacing Question
                                          idar lettrem Level 1

                                          "

                                          Sorry John about all the confusion.

                                          CS3 does not quite behave as it should do, if just found out.

                                          I cannot give you settings because i do not have CS3 anymore on my machine."

                                           

                                          well, some contributions are better than others . . .

                                          • 18. Re: Deinterlacing Question
                                            Blue_Devil1 Level 2

                                            Ann Bens wrote:

                                             

                                            Making it progressive or deinterlacing either way you are throwing a way have your vertical resolution.

                                            Now for the web its not that important but a dvd shows like its somewhat  'wooly'.

                                            BR does not alow progressive.

                                            Nowadays i only make wmvHD HDTV720 with max render quality

                                            Tried the H264: was not as good playwise. But i like YT better than Vimeo.


                                            Ann,

                                            I guess I don't understand why a progressive frame has half of the vertical resolution.  I thought that interlaced recorded every other horizontal line into two different fields for each frame, but progressive records all the lines into one frame.

                                             

                                            I also thought if you convert from interlaced to progressive, the computer places both fields into one frame so essentially have the same amount of information.

                                             

                                            I thought that was the basis of what Jeff said as to why I got combing (an interlacing artifact) in a progressive frame

                                             

                                            "Progressive H.264 export in CS3 goes back to your source footage and then looks at what the sequence is doing to it, if anything.  Since you haven't told Pr to deinterlace the footage, the AME constructs a full progressive frame out of the interlaced fields of the source.  That results in combing"

                                             

                                            Am I wrong here? Thanks,

                                            John

                                            • 19. Re: Deinterlacing Question
                                              Harm Millaard Level 7

                                              When you make interlaced material progressive, the simplest way (and the one Adobe uses) is to throw away all even fields and just duplicating the odd fields to give you a full frame. That effectively removes half the vertical resolution. I could be mistaken about throwing away even fields, it may be the odd fields, but the effect is still the same.

                                              • 20. Re: Deinterlacing Question
                                                Jeff Bellune Adobe Community Professional

                                                I guess I don't understand why a progressive frame has half of the vertical resolution

                                                A progressive frame doesn't have half the vertical resolution.  A deinterlaced CS3 frame does.  CS3 deinterlaces by throwing out one field (240 lines out of 480) and then filling in the gaps (or, restoring the 480 lines of resolution) by merely duplicating the field that was kept.  Since half the vertical resolution (240 lines) was discarded, the resulting image only has half of the vertical resolution of the original frame.  Lines 1 and 2 are the same, 3 and 4 are the same, etc.  Any detail in the image that was in the discarded field is lost forever.

                                                 

                                                Your progressive frame that shows the combing has all 480 lines because it combined both fields into one progressive frame, and objects in the frame moved between the time one field was scanned and when the other field was scanned (1/60th of a second).  One method to deinterlace the frame and remove the combing artifacts is to remove one of the 2 fields.  Once one field is removed, there won't be any combing artifacts because the remaining field represents only one moment in time.

                                                 

                                                -Jeff

                                                • 21. Re: Deinterlacing Question
                                                  lestra7 Level 1

                                                  Look this,

                                                   

                                                  http://www.100fps.com/

                                                   

                                                  for better understanding.

                                                  • 22. Re: Deinterlacing Question
                                                    Blue_Devil1 Level 2

                                                    Thanks.  I'd already checked that article out several times.  However, the author doesn't mention Jeff's point  that Premiere can create Progressive non-deinterlaced footage that will continue to show the "interlacing artifact" or making progressive footage itself doesn't halve the resolution, just the deinterlacing does that.  It appears that if one wants to output as interlaced (to get rid of the artifact), you have to do it as progressive since you are left with just one field per frame and your only other choices, I believe would be upper or lower field first ( they give me a blank screen with audio when I output them).

                                                     

                                                    He does mention the term "adaptive deinterlacing" which I borrowed from Jeff when I was talking about a hypothetical workflow..

                                                     

                                                    John

                                                    .

                                                    • 23. Re: Deinterlacing Question
                                                      Harm Millaard Level 7
                                                      Premiere can create Progressive non-deinterlaced footage

                                                       

                                                      English is not my native language, but something does not sound right here from a linguistic or logical point of view.

                                                       

                                                      Interlaced is the opposite of deinterlaced. So non-deinterlaced is interlaced.

                                                      When you have only have two choices, like positive and negative, then non-negative is positive and vice-versa.

                                                       

                                                      So what is progressive non-deinterlaced? Is that interlaced or progressive? Help me understand what you mean.

                                                      • 24. Re: Deinterlacing Question
                                                        Jeff Bellune Adobe Community Professional

                                                        Harm,

                                                         

                                                        Read my earlier posts.  If you don't explicitly deinterlace in CS3, then exporting progressive results in a progressive frame that contains interlacing artifacts.

                                                         

                                                        CS4 changed that behavior; if you export progressive in CS4, then Pr automatically deinterlaces your interlaced footage.

                                                         

                                                        -Jeff

                                                        • 25. Re: Deinterlacing Question
                                                          Harm Millaard Level 7

                                                          I did read those posts, Jeff, and I understand you, but I don't get the sentence:

                                                           

                                                          Progressive non-deinterlaced. That is the same as: PROGRESSIVE INTERLACED. Great that Adobe can do that, but what is the result? Interlaced progressive or progressive interlaced and what are the differences? If yes, why not?

                                                          • 26. Re: Deinterlacing Question
                                                            Jeff Bellune Adobe Community Professional

                                                            Progressive non-deinterlaced. That is the same as: PROGRESSIVE INTERLACED

                                                             

                                                             

                                                            I think he's just describing a progressive frame that has interlacing artifacts.

                                                             

                                                            So:

                                                            • interlaced footage viewed on an interlaced display device: no combing.
                                                            • interlaced footage viewed on a progressive display device: combing.
                                                            • "progressive interlaced" footage viewed on an any display device: combing.

                                                             

                                                            The "progressive interlaced" footage has artifacts because the combing was baked-in when the progressive frame was created.

                                                             

                                                            Does that help?

                                                             

                                                            -Jeff

                                                            • 27. Re: Deinterlacing Question
                                                              Harm Millaard Level 7

                                                              Adding the word from helps.

                                                               

                                                              Progressive from non-deinterlaced or interlaced material.