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View Full Version : DV Compression Happens When??



remnantpu
05-01-2006, 02:08 PM
I'm a newbie as this question will reveal, but I am a bit confused on uncompressed video and compression and all that fun stuff, so hopefully you can follow this question:

When I shoot footage on my z1u to tape is that footage compressed?

Is it compressed at all when it goes through the firewire to my HD?

What is considered lossless formats when working with all this?

Is there compression going from VT4 out to a HVR-M10u deck via firewire?

How come uncompressed footage takes up so much room, but the new FireStore FS-4 40GB can store 3 hours of footage?

Is there any other compression concerns I should watch out for?

And last but not least...Do we have a HD option in VT now? I heard it was going to be introduced at NAB?

robewil
05-01-2006, 02:42 PM
When I shoot footage on my z1u to tape is that footage compressed?Yes


Is it compressed at all when it goes through the firewire to my HD?Yes, but not any further. Going through firewire is just a transfer process.


What is considered lossless formats when working with all this?Uncompressed. In VT, it's usually an rtv file grabbed from an analog source or a rendered animation.


Is there compression going from VT4 out to a HVR-M10u deck via firewire?Yes.


How come uncompressed footage takes up so much room, but the new FireStore FS-4 40GB can store 3 hours of footage?3 Hours of uncompressed SD footage would take up about 225GB.


Is there any other compression concerns I should watch out for? As long as you capture, edit, and encode once, your edited video will have gone through only one uncompress/recompress cycle. If footage needs to be re-used, consider encoding your DV files to rtv (uncompressed)


And last but not least...Do we have a HD option in VT now? I heard it was going to be introduced at NAB?VT[5] and SpeedEdit were introduced, but neither is shipping for a few months. SpeedEdit, included in VT[5] offers HD editing. Live-production with VT[5] will still be SD.

remnantpu
05-01-2006, 04:24 PM
Sooo, when the footage is transferred to a rtv, does that uncompress it? or is it once compressed always compressed?

robewil
05-01-2006, 04:26 PM
It would free any further work from re-compression until final encoding.

wvp
05-06-2006, 07:32 AM
From a quality stand point your camera has recorded the footage as compressed. Rendering the footage into an uncompressed format will not increase the quality.

pixelinfected
05-06-2006, 08:05 AM
pay attention that when you tell trasfer by firewire is not exactly a simple trasfer, be cause internat dv codec of computer elaborate dv stream and code it.

if you work on windows and you not have other codec, you have dv microsoft encoded avi.

if you not have lots of money to buy a video card, you can buy a good codec like mainconcept codec, that help you to not loss dectails and quality.
(adobe buy that and add in their premiere pro suite)


if you check on internet you can see some test about main concept, canopus and microsoft, that recoding after recoding of dv stream with microsoft codec you loss a lots of quality after few recoding, with main concept not happened...

someone like the canopus codec be cause movie cpatured with it seems a bit shaped, but is not good as seems, be cause it apply a unsharp mask.

if you capture image with mainconcept and apply a small unsharp mask filter, you have result near to canopus, but with better quality be cause you not see some emboss effects...

if i want to apply filter on my capture, i apply it AFTER my work and post pro, but not before, be cause is not good for a work.

i not have chance to test toaster codec, than i cannot aswer about that, but if i know newtek, i'm sure that they did a good work