[Tig] hdcam aliasing and illegal luminance

R. Adam Berk blumediaprojekt at nerdshack.com
Mon Mar 21 08:16:28 GMT 2011

So I've just been through a weekend from troubleshooting hell.  A few good things did come of it, one of which is that we've without a doubt confirmed for ourselves that any mac application that uses quicktime for video i/o is completely unreliable and is under no circumstances to be used or trusted for mastering, but I digress.  I'll spare us all the immense list of details but what it all boils down to is some issues we had with recording an hdcam master.

Viewing a scope being fed 75% smoke bars coming from tape, it was clear that there was a bit aliasing.  To be expected of course.  The confusing part is that some of the aliased peaks fell above 100IRE, and some below 0IRE.  The signal coming from the smoke did not exhibit these anomalies.  The tape was first recorded on an F500, then repeated on an SRW-5500 in HDCAM recording mode.  Recording the same signal to HDSR on the 5500 did not exhibit these anomalies.  What's worse is that the actual program material also threw up illegal luminance errors here and there in the log.  Some of these errors went as far as -9 IRE and 109 IRE.  Again, the same program recorded to SR throws no errors into the scope's log, and running a full qc report on the actual signal coming from the smoke, pre-vtr, reports no errors also.

Has anyone dealt with this one before?  We usually master to SR and rarely go to HDCAM so if this is old news, please excuse my dumb question.

thanks so much to the collective experience in advance

R. Adam Berk
Creative Director
office +1.415.513.5918
mobil +1.330.310.3950
ichat   adam at ct-sf.com
San Francisco

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