3 Replies Latest reply on Jul 15, 2012 1:44 PM by YCC:-)

    Problem round tripping dpx PPro CS6

    YCC:-)

      hi, I'm having problems finding the correct dpx export settings to maintain the levels as the original video files.

       

      The project is from the 25fps 1080p DSLR template.

       

      I've tested the exporting dpx at 8bit, full range (LOG)  and over range (LOG)  options and at max bitdepth where available.

       

      When reimporting the dpx images into the same project to check levels and setting source characteristics to match exported characteristics for each file, ie: LOG where necessary including black and white points, on dropping them along side the original video the levels in each dpx are within the 0.0 to 1.0 range in the YC Waveform. My original video source file is > 1.0 in the YC Waveform.

       

      I expected to see the same waveform as source in particular for the LOG exports. My understanding is that an inverse LOG op would be done, (preview in bin certainly shows gamma applied preview on LOG sources on setting import characteristics) that the result would be identical in levels to the source. The whole point of transferring 8bit full levels video as RGB image sequences at 10bit is to be able to round trip without clipping or clamping? I've tested the various dpx import options like 8bit levels, 16bit levels or 0.0 to 1.0 all show the same compressed waveform compared to original.

       

      Source files are here:

       

      The original Canon T2i MOV remuxed to remove full range flag metadata to avoid Premiere h264 codec messing with luma levels on import. So get the full 0 - 255 luma. Used in the project above.

       

      http://dl.dropbox.com/u/74780302/MVI_0907.mp4

       

      The original Canon T2i MOV to compare with the mp4 above full range flag still on. Premiere mess's with luma levels in the naive file on import giving 16 - 235 luma. Not used in project.

       

      http://dl.dropbox.com/u/74780302/MVI_0907.MOV

       

      dpx exports as described above:

       

      http://dl.dropbox.com/u/74780302/dpxs.zip

       

      I wonder if someone could explain what settings are necessary to round trip dpx.