HD Quicktime using Avid HD DNX 145 codec in Vegas 8.0c

[Ian Stark]

I have been given about 40 minutes of interview footage that was shot on a little Sony HDR-SR10 camera in full 1080 HD. My client needs the footage converted as per the following instructions (copied from their email):

1. Interviews should be shot in HD 29;97fps non drop frame - 1080psf. Video should include timecode.

2. Video content should be provided as HD Quicktime files using the Avid HD DNX 145 codec.

I have downloaded and installed the Avid codec but the resulting filesizes are huge (about 1.8gb a minute). Is that right? Seems an awful lot. I thought full HD video was about 4 times the size of SDV - this is 8 times! Or am I using the codec incorrectly (which is very likely!)?

I am not particularly experienced with HD video so this is all new to me. If anyone could kindly give me some guidelines as to the kind of settings I should be using I'd be really grateful.

The other thing that's bugging me is that the lighting in the clips is just horrible - trying to clean it up in Vegas is proving a nightmare with such huge files.

Thanks, as always.

[Perrone Ford]

At the risk of sounding harsh, why are you prepping this for a client if you have little experience with HD?

The resulting file sizes are correct. And believe me DNx 145 is VERY compressed. About 10:1 over uncompressed HD. HD is about 4 times the size of SD if the bit rates are comparable. MiniDV (which you are probably used to) is recorded at 25Mbps. Uncompressed SD is about 70Mbps. These HD files are 145Mbps, and uncompressed HD is about 1500Mbps.

Best of luck with your project. I'd offer a different workflow to speed up what you're doing, but that might just get you confused.

Working with DNxHD on the timeline is a bear on an older machine. It's not much fun on a very powerful new one either.

[Ian Stark]

Originally Posted by Perrone Ford

At the risk of sounding harsh, why are you prepping this for a client if you have little experience with HD?.

Because I am their video services provider and they are paying me to find out how to do it and then to do it for them (because the organisers of an expo require it in this format). I admit I am inexperienced in HD work, but it's hardly rocket science. I'm just looking for some guidance as to the rules. If you're telling me the resulting filesizes are correct then I must have got it right first time, ergo I am more experienced with HD than I thought ;-)

Originally Posted by Perrone Ford

Best of luck with your project. I'd offer a different workflow to speed up what you're doing, but that might just get you confused.

You could try me? I might not be experienced with HD but I learn fast and can follow instructions.

Originally Posted by Perrone Ford

Working with DNxHD on the timeline is a bear on an older machine. It's not much fun on a very powerful new one either.

I've discovered this. I am working on a quadcore which whistles through heavily corrected SD footage - but now it's crawling. More expense on it's way!

Thanks for the advice, Perrone.

[Perrone Ford]

The particulars of on online-offline workflow are just a LOT to type. Essentially, with Vegas, it works this way.

Create a folder structure that looks like this

\Files
\Files\Original
\Files\Working
\Files\SD

Essentially, you do a batch conversion of the original source files into SD files into the working folder. You edit those. Color correct, and put the entire project together with the SD files. This goes quickly.

When complete, close Vegas. Move the SD files into the \SD folder, and move the Original files into the working folder. If the files all have exactly the same name, when you open Vegas, your SD files are now automatically replaced with the full-sized originals, and you can produce your master.

In theory, this is quite simple, and it's a well recognized workflow from home users to Hollywood. You'll find it referenced as "proxy editing" or "Onlne/Offline Workflow". It works well. There are a few gotchas you need to be aware of though. The MAJOR one is making sure your converted SD files have the same color as the originals. This is not as trivial as it seems. Many codecs change the color space, or do other things that make this not as seamless as it should be.

In general, if I am going to be doing this, I create TWO sets of files. One is the SD, the other is a set of high quality HD using the SAME CODEC as I used for the SD. That way, I can be assured that whatever I do on the SD files, will be EXACTLY the same as what happens on the HD files. If you are doing critical work, I recommend this, though it does take longer.

If you have a second PC, you can use that as your converter. Convert the SD files first and start editing, while the secondary computer is busy processing the conversion of the HD replacements. This is usually how I work when doing more critical work.

Make sense?

[Ian Stark]

Absolute sense, Perrone, many thanks for taking the trouble to post. I'm sure others will find that extremely useful as well.

Now, if some bright spark would write a script to do all the conversion etc . . . . ;)

[Perrone Ford]

I've posted several times about how to do the online/offline workflow. Other people have as well. The problem is that people who need it, don't know what it is, so they don't search for those answers. So someone has to suggest it and post it every single time.

And there are already scripts to do this. Search for "Gearshift".

[Ian Stark]

Your patience and kindness do you credit, sir.

[Perrone Ford]

You caught me on the right day....

[Mike Calla]

Originally Posted by Perrone Ford

You caught me on the right day....

Perrone, Any you day you post IS the right day!

Gearshift is pretty good, used it for a while! Makes life easy when using proxies... and its only 50$.

Ian, the Avid HD DNX 145 is quite robust for a reason because the majority of work is most likely coming from film >telecine > DPX and then to DNX(or very high bit-rate video to DNX).

If your source footage is from a handycam, you don't need to edit with a codec used for film. (you can render to this codec though just fine).

Have you thought about using a visually lossless DI codec with a smaller file size. I'm a big proponent of Cineform. They have a 100$ codec called NeoScene. Its a great quality codec with manageable file sizes made specifically for HDV, AVCHD, and Canon DSLR files. Edit with this, then output to your DNX format.

If you are looking for a more control, they have NeoHD for 500$ which is what i use.

my 2 cents

[Perrone Ford]

Mike makes an excellent point. When I do non-critical jobs I edit in DNxHD 36. It's not lossless, but is a LOT easier to edit. I also do proxies with this codec for the color control purposes I mentioned above. Makes things a LOT easier.

The other great thing about the DNxHD codec stuff is that if you should ever have to hand materials off to someone else who works in another editor, whether that's Avid, Final Cut, Premiere, and whether they are on a MAC or PC, it makes no difference. Everyone can read the files, and everyone can write back in the same format... For free.

Vegas is not particularly good at collaboration. It's a huge weakness in the program that they are trying to address. But DNxHD gives it a leg up in this department. Cineform is also portable, but if you need to go PC <-> Mac, you're into the $500 a seat price range.

[Mike Calla]

Originally Posted by Perrone Ford

Cineform is also portable, but if you need to go PC <-> Mac, you're into the $500 a seat price range.

Actually cineform NeoScene can be used on both mac and pc... its just a wrapper that is used. in the past i've never had to do it but recently I gave my files to fellow on mac, and rewrapping for him was quite painless. All he needed on his mac was the free cineform codec reader...(in all honestly, to my disdain, he stubbornly transferred to prores haha)

Anyway Ian, Perrone and I are just giving a you few options, there are others that might work just as well/better for you. Research and try, before your deliverables end up being undesirables!

PS Your clients may in fact accept test footage well before your deadline. When outputting to various formats i've never dealt with before, on many occasions the TV station, distributor, or client etc has accepted a small sample tape/file. they can pop in the tape/load a file, check their waveform monitors/ audio levels and give you a thumbs up or let you know if you need to adjust something for them. Who knows, maybe one hopeful there will be a universal codec for capture/edit/master:)

[Ian Stark]

Thanks guys. All very interesting and useful.

My original question was really just to clear up whether those filesizes were correct or not and whether I was using the codec settings correctly. They seemed larger than I believed they should be (although that was based on a misunderstood premise). In any case, the organisers of the expo where the footage is being shown have specifically stated DNxHD 145 so I don't have any say in the matter.

Actually I did research various alternatives before posting, including NeoScene. It looks excellent, but the trial version kept throwing up errors and I am on a tight deadline to get these materials to the client so I don't have the luxury of being able to tinker. I will take a closer look and see if I am allowed to raise a trouble ticket on the trial version when time is a little more available (some time in 2012 at this rate).

I have no immediate need to move completely to HD production (from a client perspective - mostly fairly low key corporate and training videos where the clients are very budget conscious), but I know that I must start to make that move sooner rather than later.

[Perrone Ford]

Oddly Ian, I find HD production to be quite a bit cheaper than SD production. No decks, no tapes, no waiting around burning hours to ingest tapes into the computer...

Even writing to BluRay for me is cheaper than my old tapes. I am paying $2.60 for 25GB BluRays. Cheaper than my old miniDV tape costs. I wouldn't go back. If someone handed me a tape I couldn't deal with, I had to run to the TV station and beg them to convert it for me. Now if someone gives me something I can't handle (which is pretty darn rare) I download software and covert it myself... usually for free.

MUCH cheaper and easier.

[Ian Stark]

I was really thinking of having to replace my edit pc - not to mention the camera - but it's something I am keen to do so I look forward to enjoying these benefits!