• Compression Techniques

  some basic math

  Posted by Jason Brown on March 16, 2010 at 2:05 pm

  I just want to verify that I’m doing this correctly…

  I have some old archive AVID same as source clips and I want to transcode them to an “archive” but space friendly format…so I’m doing h264 with a fairly beefy bit rate…but I have black blanking on that footage that I want to remove…so I need some help with some NTSC D1 math…

  It’s 720×486 D1 footage (1.2 PAR) and I want to crop off the black blanking and resize to full-size video…864×486 square.

  I figure out my left crop to remove the black bar on the left side…do the same number of pixel crop on the right (to keep the video centered).

  Then multiply that number – 24 – times 1.2 for widescreen to give me the “relative” number of pixels that I cropped. – 28.8 (round to 29) Then do an equation 16 is to 9 as 29 is to — 16.

  So I crop 8 off the bottom and 8 off the top.

  Then I transcode to the final with distort in the transform property to 864×486…full D1 size…

  Does that math sound correct?

  Jason Brown replied 16 years, 5 months ago 1 Member · 0 Replies
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