Urgent help needed with Correct editing codec -XLH1

[Dominic I]

Finally i'm getting to use my HD edit system to edit a bit of HD (well HDV) I've shot a load of footage on an XLH1, st to the i mode which shows as 50i in the view finder (correct me if i'm wrong but this means 25fps interlaced i.e 50 fields).

Using my decklink HD editing card, Prem Pro 2 and the XL1H i'm capturing the footage. I have the Canon codec installed but notice that it refers to prograsive? is this the correct one?.

As i have HD-SDI i would rather use that if i can, i understand that i can use the HD-SDI socket on the XLH1 to capture the image and using the Firewire socket as the device control. Which codec should i use.

Here are few options i have

Adobe HD-SDI 1080i 25fps says it's for AJA Xena card (interlased 10 Bit)

Adobe 1080i 25fps (sony50i) via firewire

Black Magic codec (the card i have) 1080i 10bit RGB 50i


I've heard about the dvcPro HD codec, but that does'nt seem to be on my system.

Need help ASAP as not long before the camera goes back (it's on Hire)

[PaulD]

Hi
Capturing with a BlackMagic DeckLink card via HD-SDI it would be conventional to use the BlackMagic codec.

The FireWire capture option will give an HDV ingest.

A DVCPRO HD codec would come from someone like Cineform - its only part of QuickTime with Mac OS X.

[Alan Roberts]

If you've shot interlaced, then you need the codec to understand that, so you shouldn't use anything that claims to be progressive. The reason is that any time you do any processing (like keying, grading etc) the interlace option will treat the fields separately, while a progressive coder will tkae the entore frame together and do nasty things to the motion.

If you capture via Firewire, you're ingesting the MPEG data stream and will have to decode it for viewing/processing. If you can get it in via HDSDI, then all the decisions are yours, so long as you understand what bthe coders do, you should be fine. But I have no detailed information on any of them.

[Dominic I]

Just had an email back from Blackmagic (decklink), god there support is fast. They suggest using one of there presets 1080 HD - Uncompressed 8-bit YUV 25fps 50i 4:2:2 so i'll give that a go. As for the HDV via firewire, i'm going to give those adobe presets a go. I'll let you know how it goes

[NickHampson]

I'm not sure of the point of ingesting HDV footage over anything but firewire, you will not gain and quality as the footahe is already HDV, capturing over HDSDI will just give you massive files but exactly the same footage remember
HDV is 25Mb per second, uncompressed HD or HDSDI is 1.485Gb per second (I think) you would need to have a massive amount of storage to capture and it had better be really fast to give you editing ability, typically uncompressed HD can only be edited on RAID disk units and thats not just software RAID of internal SATA disks.
The blackmagic codec and boards are great but run their disk test utility first to see if you RAID is up to the job and see how much space you require (typically SATA drives slow down as they start to full up and cant be used fully for this type of capture).
If you need the final precession of 10bit for grading/correction and VFX you can just use you standard HDV sequence is premiere pro 2 and nest it into a v210codec (adobe HD 10bit) or your BMD 10bit.
As premiere can process all effects etc all full 32bit (there is a check box) you might as well save terrabytes of disk and sluggish performance and just edit the HDV.
Editing HDV is a little limited but I cant see a need to go uncompressed (BMD codes are) you could look at their full raster JPEG codec for capture which is still small in file size but gives you simple discreet frames and non of the MPEG IBP stuff which can be a slight hassle to edit.

[Alan Roberts]

There is a potential advantage to working via HDSDI, just as there's a potential advantage to working SD via SDI rather than Firewire. The potential advantage lies in the filtering. When you ingest via Firewire, you're fully preserving the digits, but you're at the mercy of the filters in the software decoders, which may not be particularly good. When you work via SDI/HDSDI, you're probably invoking professional filtering, which will certainly help. You tend to see the advantages in terms of cleaner chroma, with less aliasing. I know this is counter-intuitive, but it can happen.

[NickHampson]

Alan I think this is a legacy thing with older editing systems and versions, there is now certainly no need in premiere to do this if you wish to do stuff at greater precession there is just a check box.
Choose Project > Project Settings > Video Rendering and then select the Maximum Bit Depth option to have Adobe Premiere Pro process an effect at the highest possible quality. Keep in mind that this option uses lots of processing power.
Adobe Premiere Pro can process all effects at an 8-bit color depth in the RGB colorspace. Some effects can be processed at either 16-bit or 32-bit (floating point) depth and some in the YUV colorspace.

The only reason for any other trick is to output 10bit files in which case put you sequence into a a 10bit v210 or BMD sequence you could even colour correct at this point.
FCP has same abilities and I anm sure the same of Avid, Vegas and the rest.

[PaulD]

Originally Posted by NickHampson

FCP has same abilities...

Hi
DVCPro HD has almost universally been used to edit HD in FCP, rather than uncompressed HD – but the edit can be treated as an offline, and an uncompressed timeline conform/re-render is sometimes done before transfer out to D5 tape to get best results with colour grading/compositing.
The new ProRes HD 4.2.2 codec is changing all that in the Mac world, as although 6:1 compressed (with manageable data-transfer speeds) it appears to give as good results as uncompressed HD for multi-matte colour correction etc.

[StevenBagley]

It's not to do with bit-depth (directly) it's to do with reconstituting 4:4:4 RGB from the 4:2:0 DV or HDV signal on tape, and it is the quality of the filtering that makes the difference (and it varies from codec to codec). Certainly, I've found my best results with greenscreening DV have come from bringing it in via SDI from a DSR1500, with the next best results being from one of Graeme Nattress's plugins.

There's also an issue about whether the DCT/iDCT are performed in 10bit space of 8bit space -- theoretically you should actually get better than 8bit performance by doing the conversion to and from compressed DV in 10bit space directly rather than as most software codecs do decompressing to 8bits and shifting the bits up.

Steven

[Alan Roberts]

Nick, it certainly isn't legacy, Steven's right on this. It's down to the filtering used, decent filters are expensive to make, big in hardware or grunt-worthy in software. If you don't use professional filters you don't get a professional result.