AQOF2 capturing question - kinda urgent

OK guys this has turned into somewhat of an argument over time here.

in the process of figuring out which effects to use in the film i have always captured small snippets of footage to play with but never tried to harness the full quality of what we captured.

The cameras are Sony VX2000s

Now, the only legal capturing software we have is Adobe premeire 6.5, Final Cut pro, and Avid Xpress DV -

The effects have to be done in AE.
Now I have been under the assumption that if i set Premeire at uncompressed DV format through firewire, i get exactly what a shot. is this correct or am i being lied to?I hear that avid captures in OMI format, but i didnt think that Adobe can read that. what is the difference?

Would it not be better just to work with Adobe products if that is what you know how to use and work back and forth with?

if i capture in OMI wouldnt i have to render out to a file adobe can read anyway therefore "losing quality"

now that we are in the long process of archiving all the raw footage from minidv to CD (i wish it could be dvd), i need to have the correct info before we waste media. HDD's dont last forever, but i can make enough copy sets of the core footage for editors to have.

Educate me, please!! Rive, you guys did duality on the mac, if you had edited on a pc, do you think the overall quality of the film would have been compromised?

 

I was always told that capturing DV through firewire was essentially "downloading" the footage from a tape archive device. If so, it's being PC will make no difference and the Premiere capture will be fine - although you should try out the freeware Zwei-Stein, which has a small, simple, efficient DV capture tool.

-Paul

 

DV/DVCPro codec in Premiere appears to be lossless, but I am not 100 percent certain about that. As such, you should always go back to your original source tapes via a batch capture list and an edit decision list (EDL).

Can Avid XPress read EDLs and Batch Capture Lists created in Premiere (or exported into raw text)? If so, create an offline editing master for Premiere, a batch capture list, and an EDL for the Avid XPress editors on your team to follow when they work with the full-res final edit.

It may take some time to set up the EDL parameters for proper export to Avid... but in the end it would save you a lot of time and horror, I think.

That being said, if you do use Premiere on a PC, I'd prefer you use Quicktime DV/DVCPro instead of DV AVI. AVI never seems to look right to me. I'm certain the compression algorithms for QT DV and DV AVI are slightly different... even if the final product appears somewhat the same. That being said, it's worth a try on a PC... my brother in law uses Premiere on a PC with DV AVI and the image quality seems about as good as mine... as far as the average eye can tell.

Although I have less systems integration problems being that virtually every other multimedia software I interface with... be it ProTools, or what have you... is available for Mac.

 

If it was me? I'd use Final Cut Pro. Apple's firewire capture capibility is stellar. Even in it's freebee iMovie, I've never experienced a dropped frame and exporting to Quicktime is uncompressed and very clear.

YOu could then take your QT files and import them into AE.

 

Problems with firewire capture, in all fairness, are not generally an issue with the platform... usually it's the device control drivers. If you have a sufficient device control driver for your camera, then you shouldn't be dropping frames at all.

As the other person said, it's like downloading the data... it does not get digitized, like with a capture card. It already is digitized on the MiniDV cassette... all the firewire transfer is doing is copying the digital data from one storage device to another and compressing it (typically with DV AVI or Quicktime DV/DVCPro).

Uncompressed D1 NTSC video is typically 27MB/sec... whereas MiniDV using the DV AVI or Quicktime DV/DVCPro is compressed to about 3.6MB/sec. You will definitely need a processor and memory fast enough to buffer the firewire capture while it's compressing... because the tape keeps rolling in playback. Most device control drivers, as far as I know, cannot slow down the deck to continue capturing to compensate for buffering delay. The AD (Analog to Digital, sometimes called "A to D") or DAC (digital-to-analog) converters are kind of out of the picture... but the sample & hold buffer is still an issue. A "Sample &Hold" buffer is a necessary component of any digital recording/playback system (e.g. CD/DVD players)... in computers, it's dependent upon your CPU/FPU, L1/L2/L3 cache, memory speed, hard disk speed and the logic board's quartz crystal internal clock.

Drive speed requirements are still a factor... but miniscule compared to uncompressed D1 video.

 

Note that the DV *compression* happens before it HITS THE TAPE.

So you are downloading an ALREADY COMPRESSED DATA STREAM and simply storing it in a wrapper format (QT or AVI).

As long as you ONLY EDIT (no effects, nothing, no change to the clips whatsoever), and your editing app has a brain larger than a pea, then your output footage will be BIT IDENTICAL to your input footage.

Only when you start to do stuff, i.e. in AE, does which codec your *computer* is using matter.

NOT for capture. Only when you ALTER IMAGE DATA in *any* way. Even changing the audio causes the data to re-render.

Most people vouch for the MainConcept DV codec. Or use a lossless codec like HuffYUV for all intermediate storage and only go back to DV for your final film - if necessary, otherwise direct to mpeg for your DVD's.

/Z

 

So you are downloading an ALREADY COMPRESSED DATA STREAM and simply storing it in a wrapper format (QT or AVI).

Yes, but DV/DVCPro codec compresses the 4:1:1 compression even further on hard disk. Furthermore, both DV AVI and Quicktime DV codecs convert the YUV component data to RGB composite data.

For more info on Quicktime DV codec optimizations, see developer documentation. Be aware that the developer documentation is concerning Quicktime 5, which has since been replaced by Quicktime 6... but the basics of their DV codec schema are definitely there.

However, I should add that the data are decompressed when clips are in playback in Premiere... and recompressed again when you render to a movie file... but to whatever compression schema you use. The original clips, as they are stored on the drive, immediately upon capture, are compressed again on top of the native 4:1:1 compression inherent in te DV medium... but they are decompressed for previewing and rendering. So in a sense what MasterZap says is true... in that the final output is being rendered from a decompressed file... but what's sitting on your hard drive is a compressed file. You can watch the progress detail to see how each frame is rendered: 1. decompression from DV codec, 2. Rendering. 3. Recompression to whichever codec is designated for output in "Project Settings."

 

but DV/DVCPro codec compresses the 4:1:1 compression even further on hard disk

No.

You are confusing the colorspace "compression" (4:1:1) with the data compression. The data is already compressed into a 25 megabit-per-second (= 3.6-ish-megaBYTE per second) bitstream ON TAPE. It's already in "DV format" there.

This is bit-identical downloaded to your PC, wrapped in a .avi or .mov wrapper, but the datastream is intact. NO compression is added. Actually in the .AVI case most often the audio data is uncompressed and store in a separate .avi channel redundantly so it's actually LARGER when it's stored in a file than the raw data.


Btw, DV is a YUV format and it is stored in YUV. Yes when you PLAY it in premiere it is "uncompressed for display" on your screen... not necessarily to RGB either, coz it is OFTEN done using a hardware "overlay" very common in todays graphics cards, and those actually often support YUV directly! Too.

As soon as you add an effect, though, it's transcoded to RGB, affected etc, and then compressed to whichever output codec you have chosen. THAT is where your software codecs ENCODING capability comes into play. Before that stage, for PURE EDITS, bit-identical data from your camera is happening.

/Z

 

Wow, I thought I knew some of that stuff, then you guys blow me outta the water!

But to go back to the original question, I do believe that Avid has it's own proprietary format, that being OMI and I am pretty positive you cannot import that to any Adobe products. You would have to export it in a format such as uncompressed AVI or soemthing to that nature. That is probably a workaround for you. I have been editing this low budget horror film exclusively on Premiere 6.5 and have only had a few little glithches here and there. The next project we want to do all on Avid, but we have to wait for the new budget to determine that

Since I think you guys have been working on this for a while, I would go with what you know works. NEVER change your process in the middle of a project! Learn Avid on the side as you go, then the next project your not going in at the bottom.

Anyway...

 

You are confusing the colorspace "compression" (4:1:1) with the data compression. The data is already compressed into a 25 megabit-per-second (= 3.6-ish-megaBYTE per second) bitstream ON TAPE. It's already in "DV format" there.

I know the dif. btwn color space and data compression...

This is bit-identical downloaded to your PC, wrapped in a .avi or .mov wrapper, but the datastream is intact. NO compression is added. Actually in the .AVI case most often the audio data is uncompressed and store in a separate .avi channel redundantly so it's actually LARGER when it's stored in a file than the raw data.

Thanks for clarifying this... I knew it gets decompressed from the DV tape, but I wasn't 100 percent sure if the relationship between the on-tape compression and the on-disk codec was 1:1. Apparently it is.

Secondly, in the case of Quicktime DV, the audio is uncompressed in a separate channel, stereo interleaved, at either 16-bit depth 48kHz sampling freq., or 12-bit depth and 32kHz sampling (Some Sony camcorders still use this format which is below CD-DA spec clarity).

Btw, DV is a YUV format and it is stored in YUV. Yes when you PLAY it in premiere it is "uncompressed for display" on your screen... not necessarily to RGB either, coz it is OFTEN done using a hardware "overlay" very common in todays graphics cards, and those actually often support YUV directly! Too.

Yes.

As soon as you add an effect, though, it's transcoded to RGB, affected etc, and then compressed to whichever output codec you have chosen. THAT is where your software codecs ENCODING capability comes into play. Before that stage, for PURE EDITS, bit-identical data from your camera is happening.

I'm not sure if this is the case for both Quicktime and AVI. Quicktime DV may be the same, but that developer link seemed to indicate that Quicktime itself is inherently RGB. Now since the release of Quicktime 6, there have been color compression issues with the RGB that may have been further resolved, over prior versions... with the current DV/DVCPro codec. Perhaps that codec now stays YUV component for raw, unmodified footage, and implements RGB composite only when rendering modified clips.

 

OK - Thanks for all the replies so far. this is what i've gathered from it at this point.

*DV compression by default on tape is around 3.6 MB per second.

This corresponds to the numbers I got on the first scene when it was captured in premeire and burned to discs - we were getting around 4 megs a second.

*Now playback of those files may not be at full quality from what i understand premiere uses low playback as it is, you will never see it's full quality because of software constraints. which just sounds odd to me, because looking at the footage on the Mac laptop, it just seems so much clearer on first glance. It may be my eyes, but that footage has a "wrapper" added to it, the quicktime format in either Imovie or Final cut pro - i think the transfer rate came out to around 5 gigs a minute.

So if Avid uses a proprietary format, there is no way to view that footage in another program without adding a codec to it first, or can I export to DV format from OMI? And that being prorietary, thats just to have people stick to a format or program, right? kinda like the difference between NTFS and Fat32? maybe thats a bad comparison.

But regardless, a capture in premeire is bit by bit acording to the numbers and i should be ok doing the capture in there.

The only reason I would want to use avid would be because its the more accepted of the programs in the industry, right?

To be perfectly honest I was impressed with the ease of use in the Mac Imovie and FCP programs. Compared to the other programs, It was like making coffee versus building the coffemaker first just to make coffee.