Frank's Q was pretty good:
newmedia.com
MPEG All the Way?
By Andy Ihnatko
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You're not dealing with the same MPEG 2 at every step of production.
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Q If I'm going to create a DVD with MPEG 2 video, doesn't it make sense that I should acquire video clips using Sony's MPEG 2-based Betacam SX (rather than DV or DVCPro50) so I can stay MPEG all the way? -- Frank Croft, Cambridge, Massachusetts
A No. Next question.
Oh, all right. The problem specific to DVD is that while you are indeed dealing with MPEG 2 all the way through, you're not dealing with the same MPEG 2 at every step of production. No matter how simple or convoluted the path is from photons streaming through a lens to ones and zeros being burned into a DVD, the last step will always involve decompressing and recompressing the data to another bit rate, especially since DVD video is most often variable-bit-rate. So if your eyes got all misty upon hearing about "Staying MPEG All the Way," well, there's just no "there" there.
If you're comparing the SX to a plain DV camera, though, you would at least benefit from superior color resolution; regular DV records 4:1:1 video, whereas Sony's Studio Profile MPEG 2 calls for 4:2:2, which means that the SX does twice as much color subsampling and thus records a more swellegant picture. But Panasonic's DVCPro50 is also 4:2:2 (as is Digital Betacam going into an M-JPEG system, incidentally), so bang goes that advantage. |
