which codec should my master be in?

[Larry Secrest]

Hi,
Just started to produce a film using the Canon XH-A1 and Vegas7, I'll upgrade soon to 8.

I'm going to use the Cineform codec to edit 24F out of the canon.
My question is, since the film will go to festivals I'll be able to submit it on DVD. I know how to render for DVD. But what if I need a film out master? What should be my codec for the master that will/might generate the film out?
In other words is the Cineform Codex from Neo HDV good enough or should I use something else?
Thanks
Larry

[John Yamamoto]

hi
u may run a test to compare the uncompress and cineform codec
as for film out, most lab prefer to use images sequences like DPX or TIF targa or BMP for 35mm output/blow up
so u may final output as images sequences.

i think cineform is very good but may be the lab still not able to handle it properly. so on safe side is output to uncompress image sequences

u can ask the lab which format they prefer

JY

[Paul Fierlinger]

Under Tools/Scripting you will find Render Image Sequence at the very bottom.

I will be doing the very same thing you are looking into and have done some research on it.

I've been told that all labs want image sequences brought in on an external HD (or several drives, if all images won't fit on a single one). Vegas seems to offer only two options; JPEG or PNG, which are the only choices I've been quoted by several labs.

Ideally, source of images should be uncompressed avi's.

The sound track is then handled by the lab separately for conversion to an optical internegative reel.

[Larry Secrest]

OK, so if I need to go to uncompressed maybe my final edit shouldn't be in Cineform? Once I've done all the editing in Cineform I've lost some quality compared to the footage directly out of the camera, right? So should I edit the M2t then render everything into uncompressed?

[Jim Andrada]

It's my understanding that doing the captures and edits in Cineform will yield better end results as the compression scheme they use is supposed to stand up better to multiple edits - in other words, their claim to fame is that they reduce the generation to generation degradation. If you could really work in uncompressed it would be great, but not sure how practical that would be.

Maybe you should ask the question on the Cineform section rather than the Vegas section as folks from Cineform usually respond pretty quickly.

[Paul Fierlinger]

My source format is 1920 x 1080, which wouldn't run fast enough on my computer in Vegas either, so I convert down to 720p. But each scene I create (I'm an animator) I save in two sizes; 1080p and 720p, using the same names for individual clips but choosing separate names for their folders.

Once my film will be done and ready for conversion to 35 mm film, I will block my 720p files by renaming the folder and I will redirect Vegas to the original 1080p ones by renaming their folder to the 720p name. At this point, of course, Vegas will not run at full speed anymore but all my editing will be done and I will use Vegas merely to convert everything to image sequences.

I don't see why you couldn't do the same; work in Cineform but use your original avi's for conversion to image sequences. This way you will maintain the advantage of cineform for your DVDs and your uncompressed avi's for 35 mm conversion -- if and when that happens. This way you can take advantage of both worlds.

[Larry Secrest]

Hi Paul,

What do you call "your original avi's"?
Once the M2T files are downloaded to my computer and converted to Cineform Codec, I don't have original avis's anymore? If I work in Cineform as you suggest, what do you call the original avi's?
Larry

[Paul Fierlinger]

My original avi is the Uncompressed GBR24. When I am finished drawing my scene in a graphics application I export it as a GRB24 avi. Can't you do the same?

[Larry Secrest]

"My original avi is the Uncompressed GBR24."

Excuse my inexperience, but I might not be as seasoned as you are in this field.

What is the GBR24 and how do you get it ? From the M2t footage or the Cineform codec?
Thanks

[Paul Fierlinger]

Larry,

I just picked this up from an animation forum I visit:

Animation, in particular, being a form that can suffer badly from anything more than very mild compression, and hard drives being dirt cheap, it always baffles me when people choose to keep their work in lossy formats (like DivX or xVid, or any of the other MPEG-x variants) for work-in-progress or archival purposes. For me, it's a lossless (or nearly so) AVI codec like "BRG24" (or 32 when an alpha channel is required) or "Uncompressed" or "Anim" Quicktime codec - along with 48k stereo audio at the highest bitrate provided.

It will be best if I stay out of this discussion at this level. There are lots of better qualified people here who should be able to assist you better. Something to consider though is the QT, lossless format.

[Jim Andrada]

Paul

You wouldn't by any chance mean 24 bit RGB would you?

I see that you called it BRG24 and GBR24 n different posts so couldn't help wondering.

[Paul Fierlinger]

Jim, I can't blame you. It makes me wonder about myself often. Nomenclature isn't my strongest point and if you are a self-taught person such as I, who never hears any of this terminology spoken, slugging your way through manuals and posts which all become a bog of acronyms, you can get acronyms easily confused among each other.

All along I meant the AVI format configured in the Video codec Uncompressed (BGR24) RGB mode. Aren't all PCs equipped with these codecs?

[Larry Secrest]

Paul,
Thanks for your answers
Larry

[Jim Andrada]

Paul,

Don't let it bother you. I wonder about myself all the time too and even after 50 years in the technology business I have trouble with all the acronyms.

I think all PC displays operate in RGB (Red Green Blue) at up to 24 or 32 bits but I believe generally this isn't compressed. I think (and here I may be on thin ice, so "think" is the operative word) that AVI etc don't care what the frames themselves contain, just characteristics of the total file, how sound and video are interleaved, which blocks of bits represent sound, which bunches of bits represent audio etc. and doesn't care if the frames are compressed or not.

The following is a pretty good short description.

(Ref: http://en.wikipedia.org/wiki/Audio_Video_Interleave)

______________________________________________

Audio Video Interleave, known by its acronym AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. AVI files can contain both audio and video data in a standard container that allows synchronous audio-with-video playback.
______________________________________________________________

And for codec

(Ref: http://en.wikipedia.org/wiki/Codec)

A codec is a device or program capable of performing encoding and decoding on a digital data stream or signal. The word codec may be a combination of any of the following: 'Compressor-Decompressor', 'Coder-Decoder', or 'Compression/Decompression algorithm'.
_____________________________________________________

I think we get ourselves into terminological distress so to speak because "codec" can refer either to coding and decoding or to compressing and decompressing.

Since uncoded data is pretty rare in computer land, almost everything goes through a "codec" of some kind in the sense of coding - decoding

But I think when people talk about codecs here they are mostly debating the merits of different forms of compressing - decompressing.

In gross terms, compression can be either lossless (as is used for example in compressing computer programs for download) or lossy (in most video applications). In order to get the degree of compression needed for video, we typically use lossy (ie they throw away some of the information they think you don't really need) compression.

When dealing with lossy compression of video, audio, etc people make use of "perceptual models" that relate to how sensitive people are to certain aspects of the signals. It's well known that our sensitivity to color is less than to brightness, so throwing away color information impacts our perception of the video less than if we were equally ruthless with brightness data.

Here is the nub of the issue in my mind - For what purpose are you compressing the data? If all you want to do is look at it, DV or MPEG 2 are really great perceptually based compression schemes. The results look good!

But if you want to process it in a computer, things quickly become far less rosy because computers dont "perceive" things like people do. Throwing away color information is OK for us semi-color blind humans, but it doesn't make life easy for a computer trying to process a green screen shot.

And so alternative schemes for compression-decompression, such as Cineform, arrive on the scene. While still a lossy compression scheme, it's designed for processing, not just viewing by people. And since processing often means a series of repeated edits and re-compressions, it's designed to stand up well to multiple cycles.

There are a lot of such schemes, and they've all been designed with slightly different objectives in mind, and debates about their relative merits for various purposes rage on endlessly.

Hope this helps, and before everybody jumps on me, let me just say that I know I'm skimming the surface of the subject, and I also know a lot less than it may seem, so apologies for errors, but I think the flavor of what I've said is pretty close. Think of it all as a rather lossy compression of a difficult data stream!