down rez in-camera or in post?

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dogcat

Well-known member
I'm shooting a video in 720 24pn. The final will be in sd so i am wondering if it's better to downrez in camera or in post? thanks for any advice
 
I believe you can dub to tape, but that would lead to compression concatenation. It would downconvert the 720p footage to 480, but it would also compress the DVCPROHD footage to DV or DVCPRO. I'd definitely downconvert in post to uncompressed SD. This way you only downconvert the locked picture, not the raw footage.
 
Why shoot in HD if your final is going to be in SD? If you don't need a high-def master, do yourself a favor and shoot in DVCPRO50 480/24PA.
 
thanks Segarza, what is concatenation? Also i'm just learning fcp now, what is the trick to down convert?
 
thanks Barry, i did want to shoot some slow mo, and well as i thought that downrezzing gave a better image (some one had posted some pictures comparing all the rezolutions) I have not tried shooting in dvc pro 25 or 50. What is the advantage over tape (image wise). thanks, and sorry for my ignorance
 
Concatenation of compression refers to the accumulation of errors/artifacts introduced by compression codecs. For example every time you save a JPEG file more and more errors are being introduced into the image. The file is being decompressed and compressed again and again. This occurs with lossy codecs. So shooting in DVCPRO HD, then dubbing to DV would introduce more errors/noise/artifacts into the signal than if you'd downconvert to an uncompressed SD format.

Barry's right, if you don't need an HD master why shoot HD? But then maybe spatial oversampling would add some benefits?
 
Segarza said:
But then maybe spatial oversampling would add some benefits?
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But you already get those benefits, and you certainly get them better than downrezzing from HD. Remember all internal processing in the HVX is done at 1920x1080; it then gets downrezzed to whatever recording format you're ending up on. So going from 1920x1080 down to 720x480, and then compressing once, is likely to look a whole lot better than going from 1920x1080 down to 960x720, then compressing at 6.7:1, then uncompressing, then downrezzing 960x720 down to 720x480, then compressing again.

All DV50 and DV footage on the HVX is made from downrezzed HD.
 
dogcat said:
thanks Barry, i did want to shoot some slow mo,
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Then yes, you'd need 720pN for that.
and well as i thought that downrezzing gave a better image
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No, and see the post above for the reasons why.

I have not tried shooting in dvc pro 25 or 50. What is the advantage over tape (image wise). thanks, and sorry for my ignorance
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For DVCPRO25, there is no advantage (image-wise) over tape. Same video, same compression, same data.

For DVCPRO50, it's much better. You get about half as much compression and twice as much color information.
 
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