What is the best workflow? Shall I use Purifier and save back to the same codec or shall I use different codec?
First two clarifications
Lossless - means non-destructive, no data loss even for repeated usage.
Lossy - means the opposite.
In general, we recommend using a good and lossless codec, like FCP Uncompressed 10-bit 4:2:2 (v210), so that your footage may be preserved throughout the whole editing process. This will ensure that it will not be damaged more than necessary before you send it to the
next step, in this case for input to Video Purifier.
There is also a third-party codec that we really like, the SheerVideo from www.BitJazz.com. Before you ask, no, we do not get anything for saying so.
Typically, these recommendations also apply when selecting codec for output from Video Purifier. The exception is when you know that the purified movie is never going to be used for any further processing or editing, other than compression, e.g., with BitVice MPEG encoder or any other compression tool. In such case, when only 8 bits/channel are going to be used anyway, it is harmless to use an Uncompressed 8-bit 4:2:2 codec (v208) for the output from Video Purifier.
After spending money on - and using high quality software, such as the Video Purifier, you would not want to be careless with lossy codecs.
There are people who happily edit their movies using a compressed codec, destroying their footage bit by bit for every step they take and every edit or transition they make.
Maybe they do it to save disk space? If so they should instead go and get a bigger disk so they can work with video properly. Disks have become so cheap over the last few years, making it really affordable to edit video in a lossless environment.
Maybe they do it just because they are not aware that almost all other codecs use lossy compression. To mention a few, every type of DV, DVCPRO, H.264, HDV, JPEG, MPEG, XDCAM or Apple codecs (except the
v210) are lossy and therefore sub-optimal to use for anything but the very last step of the production chain.
For the first step, though, you are limited of course by which camera and type of video capturing equipment was used. However, even if a movie originates from a DV or HDV camera it is still perfectly allowed to up-convert it into Uncompressed 10-bit 4:2:2. It is a good idea too, for quality reasons, to do that before doing any serious kind of image processing on it. That is, if you can at all afford the necessary disk space.
I have BitVice and DVNC. Do I really need Purifier?
Purifier is different compared with DVNC. Purifier is more adaptive and is a lot better detecting noise. So the answer is yes; you need purifier.
Can Purifier be used for scaling video to SD from HD or HD to SD?
Yes Purifier uses a very advanced 3DFIR filtering technique to scale your video. But it is not handling frame re-rating.
Does Purifier preserve alpha channel during processing?
As of version 1.3.6 it does not.
I'm using Apples FCP so please tell me about the workflow?
That depends pretty much on your setup. Basically the flow is straight forward;
- Capture the movie as you normally would have done
- Export the clip into a file using the same or better codec you used for capture
- Purify the video with Purifier using a high quality codec
- Import (recapture from disk) into FCP
- Use color/gamma correction if needed as you normally should have done with your captured video
