Brian Alexander
Forum Replies Created
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Long story short: only deinterlace upon output when your ready to go to the internet or distribute for computer use.
The long story…
The links Daniel provided are a great resource for learning about the science and practice of interlacing/deinterlacing. However, what you will not find in these resources, in plain English, are the practical instructions for when to de-interlace and when to leave well enough alone.
You typically would not want to deinterlace anywhere in your workflow until the last step: prepping your file for your intended medium.
Reasons to deinterlace:
1. Creating a distribution based format (h.264, wmv, On2VP6) for the internet or computer use.
2. Removing telecine frames.
Reasons not to deinterlace
1. DVD Creation (you can burn a 29.97 progressive sequence to your DVD. What you may not realize is that your DVD Player is most likely performing a scan line decimation only to have your TV perform a scan line interpolation. To much processing!)
2. Going to tape. I think some people still use tape machines? When you lay footage to tape, it’s interlaced.
3. Providing the right codec for tapeless playback. A computer connected to a digital processor is not going to recognize a need for deinterlacing video, however, if you use the right codec and the right software, the file will deinterlace on the fly.
Interesting fact: 99 percent of the video you watch on TV is interlaced! Well, what’s really going on is that most of the video has been shot at 24p (23.98) and has had telecine applied to it to conform to broadcast standards. These interlaced signals hit your TV and the first processor it comes to is the deinterlacer or deinterleaver.
Another interesting fact: Film DVDs are encoded a 23.98 (progressive, same as film) and your DVD player adds the telecined frames to create 29.97 fps for your TV. Of course, if your TV can accept a 480p signal, it can do it at 23.98 or 29.97.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
Did you ever find a solution to your problem? How did your submission go?
Here’s what I’m seeing from this end (although it’s a moot point); the 720 x 576 (1024 x 576) is a PAL based frame. The 720 x 404 sounds like a 16:9 letter-boxed image in a 720 x 480 NTSC frame.
Just thought I’d throw it out there.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
Here’s a good reference, although it seems that the Apple Trailer dept doesn’t seem to adhere to these guidelines.
https://www.apple.com/quicktime/tutorials/h264.html
Remember that the trailers are running 24 fps (23.98) which is only 80% of a 30 fps movie.
For instance, take a 1920 x 1080 30fps movie encoded at 8 Mbps. You could achieve the same quality by encoding a 24 fps movie @ 6.4 Mbps.
The Apple 1080 HD trailers’ average bit rates hover around 9.5 Mbps. If this were 30 fps, to achieve the same quality, you’d need to average 11.4 Mbps.
TMI? Probably.
Cheers.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
[gary adcock] “Make sure that you uninstall the software using the AJA uninstaller”
Yep, did that.
[gary adcock] ” remember to reflash the firmware on each device – the IoHD drivers will conflict with the older hardware”
I completely uninstalled the IoHD drivers/software with the IoHD uninstaller don’t think I tried re-flashing the IoLA afterwards. Do you think its possible to run both of these devices on the same system?
[gary adcock] “Are you sure you can get that many IoLA’s?”
Yes. Not sure they would all come directly from AJA but there’s a load of inventory I bet distributors would be happy to get rid of.
[gary adcock] “I am currently Chair of the NAB’s DP conference”
Freeman does NAB, what a coincidence. Sounds like you do lot’s for this industry. I hope to one day be as large of a contributor as you although our particular fields slightly differ.
I was a high end projectionist/video engineer before my gig with Freeman. Check this out when you get a chance (some of my projection work): https://www.brianalexanderphotography.com/Events/2006-MTV-Video-Music-Awards/2897699_sKRA3#155915078_BJr4X
[gary adcock] “I just completed the North American KiPro Tour dates for AJA last month.”
I missed you by one day (I was taking a much needed vacation). I would really love to purchase a load of Ki Pros to get my tapeless workflow running but it’s too much work for trying to hand a drive to the client – too much file transferring on show site.
[gary adcock] “I speak mostly on Film and digital Technologies focusing on the future of HD in Production and Post.”
I’m working on developing a tapeless future for live video conferences. I hope we cross paths sometime.
I plan on getting these little issues worked out with AJA tomorrow. I’ll let you know what happens.
Thanks Gary.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
[gary adcock] “Freeman is pretty big in that field and I speak all over the world. Which city?”
I’m in the National Operations Center in Dallas but we have AV branches in Austin, San Antonio, Houston, Anaheim, Orlando, DC, and Vegas.
Where do you speak? What topics do you cover?
[gary adcock] “The IoHD is not limited to capturing only as ProRes in SD, the unit can also capture as DV25, DV50 and SD as Uncompressed 8bit if your drives are fast enough.”
I’ve done months of testing and have not found too many codecs besides ProRes that work. Looks like I’ve skipped over the DV family of codecs in my tests. I’ll give it a shot here after I get this 30 minute problem worked out.
[gary adcock] “Also might look at the new IoXpress”
This was not shipping when I had to make a decision on a product for field acquisition. The IoExpress does look attractive but I most of the SD gear used today is Component based. Additionally, I would have to get SDI/audio embedders as the audio source on show site comes from audio consoles w/xlr connectors.
BTW, the 30 minute issue seems to be intermittent which is just adding to the confusion. I thought it may be a driver conflict so I’ve uninstalled the IoHD software. First run after the uninstall worked so I thought I found the issue but 2nd test proved this is not the case.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
[gary adcock] “Then why not use the IoHD for the same task? “
I am using this product in the place of DVCAM decks for Corporate Events. I’m basically handing over files on a hard drive instead of tapes to the clients. Many of the clients are still PC based and only working with SD material so I need DV files and not ProRes. Additionaly, I’m looking at building 30 to 50 systems that are based on a MacBook Pro and the IoLA. The IoHD will only be used when we’re shooting HD.
[gary adcock] “There has not been a driver update since april 06 so using it with FCP or software released after that date is dicey at best. “
AJA support still seems up to date despite the lack of software updates. I’ve had lengthy discussions with many of the techs and I had no red flags thrown up.
Please note: I do not use Final Cut with these products. These systems are simply field recording kits or DVA Systems (digital video acquisition).
Updates
The recordings that stop at 30 min. are not limited to VTR Xchange. I’m getting the same error using Record Pro (DT Video Labs).
Internal/External drives do not seem to make a difference, I’ve received the same error regardless of drive setup.
I have not tried QuickTime Pro because I can’t control the Codec. “Device Native” is uncompressed and I’m trying to use DV NTSC or DVCPro50.
Thanks for your input Gary.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
I don’t think there’s an easy answer because of the sheer volume you have to work with. The only way I can think of is going to require each one to be done by hand.
I would create a custom setting for this job, disabling video and just compressing the audio. You’ll end up w/500 audio files which you can simply “add to movie” in QuickTime and delete the little endian audio track.
Brutal, but that’s all I’ve got.
Good luck.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
[Gregorio Pellegrino] “Is it possible? “
Sure, but quality will not exist.
[Gregorio Pellegrino] “I have Apple Compressor, is it good? “
Compressor is great but no compression software in the world is going to do what you’re asking and be able to deliver a decent image quality at the original frame size.
[Gregorio Pellegrino] “What settings have I to set?”
If you had no menus (gfx, pics, etc) you might be able to get away with a bit rate of up to 1600 Kbps for video. This will leave a little (very little) room for audio.
If you’re doing this for a client I’d dig a little deeper. You may find that they’re needs and expectations don’t mesh.
Good luck.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
Engineer? With a knife?
Call AJA let them know you have a defective unit. They’ll want the serial number of your IoHD and your shipping address. They’ll overnight you a new one with the RMA (Return To Manufacturer) information so you can send your bad unit back.
I recently had one replaced because of a defective FireWire port. Firewire is the weakest link of this product!
Anyone making a professional grade Firewire connector that you’re aware of?
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Brian Alexander
Sr Video Engineer
Freeman AVS -
Well, I only did a few seconds of progressive frames (which I’m guessing that’s what you’re working with) and here’s what I’ve found:
MPEG Streamclip very simply, just duplicates frames.
24fps in a 29.97 count reveals the following duplicate frames:
3&4, 8&9, 13&14, 18&19, 23&24, 28&29…(I see a pattern!)
That was fun.
Now for the real question…What is friend trying to do with his video? Why is he trying to do this type of workflow? There are only a couple of reasons why he’d need to change the frame rate in this way.
Perhaps a couple of quick questions would reveal some concise help to his conundrum.
Thanks.
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Brian Alexander
Sr Video Engineer
Freeman AVS