8 Replies Latest reply on May 27, 2008 3:09 AM by Mylenium

    Ram preview not completing before playback

      I press the ram preview button once and the green bar starts to grow on top of the timeline but before it gets to the end of the timeline it starts playing without my pressing the RAM preview button again. sometimes its shorter than others times. Whats causing this? please help im completely baffled.
        • 1. Re: Ram preview not completing before playback
          Andrew Yoole MVP & Adobe Community Professional
          Direct from the link posted in response to your other RAM preview question:

          i RAM preview allocates RAM to play video and audio in the Timeline, Layer, or Footage panel in real time.
          b The number of frames that can be stored for real-time playback depends on the amount of RAM available to the application and the settings in the Time Controls panel.

          i In the Time Controls panel, you can specify two sets of RAM preview options: RAM Preview Options and Shift+RAM Preview Options. For example, you may decide to set RAM Preview Options for full frame rate and full resolution, and set Shift+RAM Preview Options to skip one out of every two frames and preview at half resolution.

          http://livedocs.adobe.com/en_US/AfterEffects/8.0/WS3878526689cb91655866c1103906c6dea-7ec9. html
          • 2. Re: Ram preview not completing before playback
            Level 1
            so how would i do a fast preview of the whole thing, like in premiere pro. My other post was about the spacebar preview and i was told to use the RAM preview to keep all the frames around, now youre telling me i cant use both?! cant this stuff be stored on harddrive so i can get real time playback on my computer of the whole thing? thanks
            • 3. Re: Ram preview not completing before playback
              Level 1
              Nope ... AE works natively with uncompressed pixels so ram gets eaten up very quickly with large comps. The only way to get longer previews is to decrease comp preview resolution, increase ram, or skip frames.

              Some complain that if Motion can do realtime previews why can't AE. The answer is that they handle the data completely differently. Motion will quickly bog down with HD comps and a bunch of layers. Premiere and FCP also handle the video completely differently. The video is compressed and available to be served up by the codec and the hardware at normal frame rates. If you want the same performance from a compositing app you'll have to render to a codec that will support RT playback.

              The only way to get realtime playback of a long piece is to render it to a codec that will serve up off the hard drive and decompress at a rate that won't cause the system to bog down.
              • 4. Re: Ram preview not completing before playback
                Level 1
                I cant believe it, this has been bugging me for some time. Do other people have a problem with this? Is adobe working to fix this in future releases. My computer has 2GB of ram thats not a small amount and i can only get a few seconds of video playback at full quality.

                Im guessing playback in AE is not usually done then only timeline scrubs? or do people only work on 30 second clips in AE?

                Thank for the response.
                • 5. Re: Ram preview not completing before playback
                  Joey Morelli Level 1
                  This is not a problem...it's a fact of life. AE is not an NLE...it's a compositing & animation app. It's not meant to play back full rez which is why it's called "RAM "Preview". You can't "spacebar" playback like an NLE - you must render a RAM preview. If you want more playing time:

                  1. Get more RAM (AE sees 3 GB)

                  2. Render every other frame

                  3. Reduce quality / resolution of your comp

                  4. Stay in 8 Bit colorspace

                  5. Set your Cache Settings to 90 / 60 (my Macs love this setting)

                  How much are you trying to play back and what is your comp size?
                  • 6. Re: Ram preview not completing before playback
                    Level 1
                    i have a 2ghz dual core and 2gb ram with a nvidia 7950gt gfx card. I would like to play back 5 minutes worth of footage.
                    • 7. Re: Ram preview not completing before playback
                      Andrew Yoole MVP & Adobe Community Professional
                      The only way to make a 5 minute preview is to render it to a file. There are many options available in the Render Queue to enable faster preview renders, such as reduced resolution, reduced quality etc.

                      Be sure to render to a codec that will enable reliable playback from a hard drive. Most standard drives won't play back full resolution uncompressed video - look at Quicktime PhotoJPEG or H.264 codecs for preview renders.

                      If you have only ever used NLEs before, this workflow might seem a bit clunky, but it is logical and essential for most compositing tools to work this way. One day, when AE is a 64bit application, RAM previews will be capable of minutes at a time.
                      • 8. Re: Ram preview not completing before playback
                        Mylenium Most Valuable Participant
                        Sorry, Eddie, to chime in with the others: you are making a fuzz over nothing. Contrary to what you believe, 2GB is absolutely not much. Even at shabby NTSC and 8bpc, a frame will consume at least 2.5 MB of RAM. Also do not forget that your operatin system itself consumes almost 1GB, so the effectively available amount of RAM for AE is actually pretty minor and leaves you with a few seconds worth of preview time at most. Follow the tips the others provided and simply get used to it. I also feel that there is room to optimize your workflow. It sounds like you are doing things in AE that could just as well be done in PPro or at least made a lot easier by properly preparing your stuff there.