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Just to confirm the information I provided earlier. This morning I called
our local service bureau. When film is dubbed to video in the PAL format,
they copy each film frame twice to produce a single video record. In
other words, when an interlaced video FRAME has been produced, line 1 is
the same as line 2, line 3 is the same as line 4, etc. Thus, if your
video analysis system extracts data from every field, you will get
duplicate records consistently unless you ask for a one-to-one transfer.
My service bureau confirmed that "when you dub to PAL you take a 4% hit on
running time", but it's not considered a problem for most purposes. When
questioned about the audio (which is not likely to be a problem in our
field) I was told that the pitch of the audio track is adjusted
electronically.
I hope all this has been helpful.
Jim Walton
Chairman, SPIE Working Group on High-Speed Photography and Photonics
************************************************** *************
************************************************** *************
* * *
* JAMES S. WALTON, Ph.D. * *
* President * INTERNET: Jim@4DVideo.com *
* 4D VIDEO * *
* 3136 Pauline Drive, * *
* SEBASTOPOL, CA 95472 * *
* * COMPUSERVE: 72644,2773 *
* PHONE: 707/829-8883 * *
* FAX : 707/829-3527 * *
* * *
************************************************** *************
************************************************** *************
our local service bureau. When film is dubbed to video in the PAL format,
they copy each film frame twice to produce a single video record. In
other words, when an interlaced video FRAME has been produced, line 1 is
the same as line 2, line 3 is the same as line 4, etc. Thus, if your
video analysis system extracts data from every field, you will get
duplicate records consistently unless you ask for a one-to-one transfer.
My service bureau confirmed that "when you dub to PAL you take a 4% hit on
running time", but it's not considered a problem for most purposes. When
questioned about the audio (which is not likely to be a problem in our
field) I was told that the pitch of the audio track is adjusted
electronically.
I hope all this has been helpful.
Jim Walton
Chairman, SPIE Working Group on High-Speed Photography and Photonics
************************************************** *************
************************************************** *************
* * *
* JAMES S. WALTON, Ph.D. * *
* President * INTERNET: Jim@4DVideo.com *
* 4D VIDEO * *
* 3136 Pauline Drive, * *
* SEBASTOPOL, CA 95472 * *
* * COMPUSERVE: 72644,2773 *
* PHONE: 707/829-8883 * *
* FAX : 707/829-3527 * *
* * *
************************************************** *************
************************************************** *************