1 Reply Latest reply on Feb 5, 2012 12:43 AM by Mylenium

    Renders are choppy and lighter than preview

    Bornhald

      Hi,

       

      I have been learning AE and C4D over the last 6 months on the side treating it like a hobby.

       

      The problem: Ever since my first test render from After Effects I have had two issues: the rendered file is choppy when played back in quicktime or vlc and the frames are blown out and bright compared to how they appeared in After Effects before they rendered - to be specific, for example, I don't get any pure black in my frames; every pixel that is pure black renders as a dark shade of grey.

       

      Specifics: After doing some research I learnt that After Effects is essentially designed to spit out large lossless files which don't play back well in quicktime/vlc. Rather they are meant to be compressed in another application. Actually when I render out lossless files straight from After Effects the frame don't get blown out and lightened, but they can hardly playback in quicktime/vlc as they are extremely choppy.

       

      When I render out a compressed file - whether I do it straight from After Effects or use Adobe Media Encoder - the frame rendered are blown out and lightened AND the choppiness is still there although drastically less than with the lossless files.

       

      The project I am rendering: A scene from Cinema 4D in the form of an uncompressed image sequence (4GB file), 1080p, 30 fps, ~15 seconds long. I chucked on a couple of post effects and I'm rendering it out of After Effects at 1080p, 29.97 fps. When I render with quicktime animation I get a 1GB file which plays back choppy in regular media players but the frames do not get blown out and lightened. When I compress the file it reduces to ~20mb and the frame colour is blown out and lightened and some remnants of the choppiness and other distortions are still there. I guess the contents of the project I am rendering are irrelevant because I get the same results from any other project I render; even an empty pure black screen gets blown out to a lighter colour (a dark shade of grey) and has the same choppy results.

       

      I am searching for the answers as to why my video is playing back choppy in standard media players even with compressed files and why my frames are lightened in compressed renders. Or it least the answer to how I can render out a simple 20 second animation - or any animation for that matter - with the lightness of the frames maintained and not blown out and with a normal - compressed - file size.

       

      I would sincerely appreciate any help and support I can get. I am dying to be able to produce a stable render and am overwhelmed by the fact that I can't and can't work out why.

       

      Thanks!

        • 1. Re: Renders are choppy and lighter than preview
          Mylenium Most Valuable Participant

          Answer a:

          I am searching for the answers as to why my video is playing back choppy in standard media players even with compressed files

           

          Your computer sucks?! Seriously, if all files play choppy you have a pretty obvious configuration problem, in particular with your graphics hardware. Anything from hardware acceleration in your players not working at all to vsync issues. Additionally, your harddrives may simply be slow or terribly fragmented.

           

          Answer b

          I am searching for the answers as to why my video is playing back choppy in standard media players even with compressed files and why my frames are lightened in compressed renders. Or it least the answer to how I can render out a simple 20 second animation - or any animation for that matter - with the lightness of the frames maintained and not blown out and with a normal - compressed - file size.

           

          You need to understand data rates for compression and read up on Gamma shift issues e.g. in H.264 and other compressed formats and which encoders avoid them or which techniques can be used to compensate. One hack-y way is e.g. to simply use AE's Exposure or Level Effects and apply an inverse Gamma, but in order to not entirely ruin your footage you'll have to work in 16bpc or 32bpc modes. That aside, the issues mentioned in the first part may figure in - bad graphics config will also skew colors as will mis-tweaked monitor settings and unsuitable color profiles. And finally, you may be doing something wrong with C4D's linear workflow vs. a Gamma based workflow, also.

           

          Mylenium