12 Replies Latest reply on Oct 7, 2009 9:14 AM by Mylenium

    ae render slows down after 50 frames

    seetukka Level 1

      I have noticed this behavior growing after updating to snow leopard, but has existed before that too...


      Every time I make final render output in render queue, about first 50 frames renders quite fast. Then I hear my hard drives starting work hard and the render slows down very much. Does this mean that I just haven´t got enough RAM??


      I have mac pro 8-core with 16 gb of RAM and cs4


      Today I made 2000x2000 comp with only just some flourish stuff growing. I didn´t attach any effects but "write-on" to those objects I wanted to "grow" and still 5 sek took over 40 min to render to a QT ANIMATION. Ok, I had over 50 layers but still is the render time too long.


      I tried to render same comp with FILE---> EXPORT---->QUICKTIME and also made animation and the render time was about 5 min.


      Why is the render queue so much slower??



        • 1. Re: ae render slows down after 50 frames
          Adolfo Rozenfeld Adobe Employee


          Of course, 16 GB of RAM is adequate. It is, in fact, the recommended amount for a 16 GB of RAM.

          I assume you have "Render Multiple Frames Simultaneously" enabled, right?

          In that case, when you work with memory intensive Comps (like 2000x2000 layers), it could be good idea not using all 8 cores for rendering. This is because otherwise each rendering instance would only be able to use about 2GB and this could be counterproductive.

          In the Memory and Multiprocessing preferencesm you'll see there's a "CPUs to leave for other applications" setting. If you set it to 3, AE will spawn rendering instances for the other 5 cores, and they may get more RAM each.

          See if that helps. I suspect (but can't assure, of course) that the File > Export command is working faster simply because it's not compatible with the "Render Multiple..." feature.


          As always, I encourage you to check the AE Help page on Memory and multiprocessing preferences. It has a lot of information on this.

          1 person found this helpful
          • 2. Re: ae render slows down after 50 frames
            seetukka Level 1

            I did some tests today.


            I tried to render same 2 sek clip with different settings. Same time I looked the system monitoring window for processor and memory usage. I did notice some strange behavior..


            Fist test was open gl on and multiprosessing off


            2 sek took 2,51 min to render


            with open gl off it was 7 min


            Second was


            multi prosessing on with 6 cores in use and 2,5gb/core of ram


            with open gl on it took 5 min to render


            open gl off it was 42 min!!!


            prosessor usage was 10-20% and memory usage per background process was about 125 mb both cases.



            Third I tried with multiprosessing on but using only 2-cores.


            With open gl on render took 3,22 min


            and with open gl off render time was 8 min


            Processor usage was about 5-15% and memory only 110mb/background process


            Then finally I tested with 7-cores is use and 2,09gb ram/core


            The render started fast with processor usage in 99% and memory usage up to 2gb/background process and first 20 frames took just couple of seconds to render. But after a about 20 frames processor usage dropped to about 10% and memory to about 150mb/background processor. After that it took almost a minute to render 1 frame.


            After that I noticed this same behavior every time I used multi processing?!!!


            What is causing this??

            • 3. Re: ae render slows down after 50 frames
              Mylenium Most Valuable Participant

              What is causing this??


              Footage I/O overhead, plain and simple. After the first few frames writing the files to disk takes longer than the actual render and since each render instance finishes at different times, they get in the way of each other. In addition, when using a sequential format (a movie file) instead of image sequences, each of the BG processes may have to wait for another to finish, so frames are added to the file in the correct consecutive order. So basically, MP rendering is of no use then. This does however not apply to all movie file types, it depends on specific CoDecs. And for the record: OpenGL rendering will always only use one process. AE may start additional rendering instances, but only the main one will be used. It's a design limitation in OpenGL and quite well explains why your render times are similar when using it regardless of differences in processor settings.



              • 4. Re: ae render slows down after 50 frames
                seetukka Level 1

                I tried also with image sequence(tiff sequence) and the result was the same. After about 20-30 frames the renders slows down dramatically. Then I hear hard drives starting to work hard. Then it might take up to couple of minutes to render a single frame. Then it can take a couple of frame boost and the slow down again to render a one single frame. Is my output hard drive just too slow? With multiple render off, over all render time is much faster. With multiple off render doesn´t stop to think a one frame more many minutes, but keeps on goenig smoothly.


                I have also experienced a total freeze off my system when the aeselflink processes some how freezes the whole computer. Every thing slows down and it might take many minutes even to get to my dock. Then when I force the ae to shut down

                the aeselflinks still does something for a minute after AE has shutted down. That period of time computer is still extremely slow and hard drive is writing or reading something very fast...


                Is this normal behavior or is there something wrong???

                • 5. Re: ae render slows down after 50 frames
                  Mylenium Most Valuable Participant

                  It does sound weird, but if the behavior is the same for image sequences, something may be up. By all means, LZW compressed TIFF sequences should write reasonably fast. So perhaps the bottleneck is with the sources, after all. Re-reading your other posts, the mention of "flourishes" rings a bell. If they are Andrew Kramer's (or someone else's) pre-rendered QT files, in fact Quicktime may be the culprit. If they are vector files, using continuous rasterization may have a similar effect, as it can increase memory usage considerably. Does any of that apply here? If so, turning off those features for a test may reveal the truth.



                  • 6. Re: ae render slows down after 50 frames
                    Adolfo Rozenfeld Adobe Employee

                    Just in case, you did update to 9.02, right? It fixed a few performance issues with multiprocessing.

                    • 7. Re: ae render slows down after 50 frames
                      seetukka Level 1

                      Hey guys,


                      Yes, I have the latest update.


                      I noticed this error log everytime the render slows down???


                      Any ideas what is causing this??



                      Adobe After Effects v9.0.2 (Macintosh Intel) render log for project “FINAL GRAFFA ver2_1.aep”


                      Rendering started on 5.10.2009 at 12:31:22


                        5.10.2009 12:31:22: Starting composition “uusi grafiikka leikattu 6”.


                        Output To: Macintosh HD:Users:jonykarlsson:Desktop:ATMOSPHERE3:uusi grafiikka leikattu 6_[#####].tif
                         There is an error in background rendering so switching to foreground rendering after 6 frames completed out of total 125 frames. (26  ::  142)
                        Render stopped by user.
                        5.10.2009 12:34:52: Finished composition “uusi grafiikka leikattu 6”.




                        Total Time Elapsed: 3 Min, 13 Sec


                      Log closed on 5.10.2009 at 12:34:52

                      • 8. Re: ae render slows down after 50 frames
                        Mylenium Most Valuable Participant

                        Ah, now things become clearer. Then it probably slows down due to trying to re-initiate the background instances and throwing a lot of resources at it. I suggest you try this tip and see, if it improves behavior:





                        • 9. Re: ae render slows down after 50 frames
                          seetukka Level 1

                          Hey, Mylenium


                          I read your tip, but was unable to perform it. When trying solution A this is what happened:


                          Last login: Tue Oct  6 09:43:00 on console
                          Macintosh:~ jonykarlsson$ hwprefs cpu_ht=false
                          -bash: hwprefs: command not found
                          Macintosh:~ jonykarlsson$


                          And solution B, when I tried to save the script it said something like:


                          syntax error,

                          Waited for target "given", "if", "of", "sentence","with", "without", other parameter etc. but found unknown token.


                          This is a free translation of the message, cause my os is in finnish:)


                          Did I do something wrong?

                          • 10. Re: ae render slows down after 50 frames
                            Mylenium Most Valuable Participant

                            I'm sorry, I can't really help you with that. Someone forgot to send me 5000 Euros for a MacPro. The user who offered this tip on this forum here may be able to figure things out. Try a search and I'm sure the topic will come up. Was only a few weeks ago, so the otehrwise pretty lame search may still find it (else try the mighty Google).



                            • 11. Re: ae render slows down after 50 frames
                              seetukka Level 1

                              I tried to find the topic but couldn´t find it...


                              I talked to a adobe stuff today on Finnish AV-EXPO and he told me that they are aware of this issue on ae cs4 multiprocessing. They said it has something to do with a mediacore. They don´t know what the bug is but they are trying to fix it as we speak... They said it might take a while though, cause they´ll have to locate the bug first...


                              While waiting for the update, I´m plannig to buy Nucleo Pro 2 to get the render work faster...I´m still a student so I get the educational discount from it... Do you think it will work? Does Nucleo use adobe´s own mediacore or does it some how overwrite it, so that the bug doesn´t affect it???


                              Thanks alot for your help so far,

                              • 12. Re: ae render slows down after 50 frames
                                Mylenium Most Valuable Participant

                                Well, NucleoPro uses AE's I/O infrastructure, which would include MediaCore. However, it uses a slightly different model for its "multiprocessing" that seems to isolate the render instances more robustly, so this may work after all. I realyl can't tell you, as except formy MacBook I'm a PC guy and those issues obviously only afflict Macs. Well, anyway, ping the people at GridIron and have them send you a test license, so you can find out...