Brian Alexander
Forum Replies Created
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Hi Craig,
Yea, the audio drift is related to the recording – audio is solid when viewing the ‘live’ source. It’s the same type of drift found when inadvertently recording or transcoding a 44kHz source to 48kHz.
You bring up a good point about VFR encoding. I’m guessing the audio and video run through their respective encoders before being combined in their output container. If that’s the case it would make sense that complex video scenes may drop the frame rate slightly while the audio encoder is sailing right along with no problem. This may cause the delay that is being reported.
Is the only way to take advantage of Matrox Max through the ISO recorder?
What is the difference between choosing the Matrox source under MATROX INPUT DEVICE vs. the Matrox source under the SYSTEM DEVICES in the Source Settings preferences?Thanks for your help Craig.
Much appreciated.—
Brian Alexander, ISF, ISF-C
Sr. Video Engineer
FAV -
This is not the way a compressionist goes about getting content to fit onto a DVD.
The idea is to compress media (video, audio, animation, gfx, etc.) with compression software. The amount of compression depends on 2 factors: File Size and Quality. The point is YOU control the compression, not software.
That said, when we’re in a pinch, we do what we can to find what works and we make it work. Next time you may run across across the practice of bit budgeting. Have a look at this: Bit Budget
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Brian Alexander
Sr Video Engineer
Freeman AVS -
The stations that are broadcasting at 720p do not limit their content to 720p only content.
The only way we’re seeing true 720p content from start to finish is when a shoot/edit is done in 720p and our cable box is set to 720p. This is not as common as a shoot done in 1080i or SD.
Content that is not 720p that is broadcast from 720p stations include the following:
Film @ 23.98 -> 29.97
SD Video @ 29.97
HD Video @ 1080iThe point I am trying to make is that most of the material has passed through a deinterlace processor somewhere in the chain.
Let’s say your TV is set to 1080i and you’re watching a 720p station, the progressive signal is processed by the cable box to upconvert and introduce scan lines only to be deinterlaced by your TV.
The original question was about interlacing, what it is, and when to deinterlace. The answers I provide are from a viewpoint of a compressionist and video engineer.
My 99% figure for interlaced material may have been off by a few percentage points, I’ll update the quote after I get home from NAB next week.
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[Paul Raila] “I export from FCP as a Quicktime movie (no compression), making the movie self-contained. Image still looks great at this point. “
You could export a reference file, it would save you time by not creating a stand alone file.
[Paul Raila] “Here is where the problem occurs, I think. I compress, and my footage looses quality”
Your creating a downconverted standard def file. It is going to take a hit in quality, this is normal.
[Paul Raila] “How do I maintain the clarity I began with while exporting to a SD DVD file?”
What are you viewing this encoded DVD with? Are you looking at it on your computer and letting your computer scale it to full screen or are you looking at this on a DVD player connected to a CRT?
The way to view this file on your computer would be to view it at a 100% zoom or actual size with the deinterlacing filter turned off. This will look pretty small on your monitor if you’re running at a high resolution but it will give you an accurate representation of what the quality really is.
[Paul Raila] “Can I do H.264 maybe, and import that into DVD Pro? “
I wouldn’t do this. You would be essentially compressing (transcoding) the video twice, you won’t get a good result like this. This would be the same as recording a video from HDCam SR to HDV to DVD. This analogy is not perfect but you get the point, generation loss each step.
I don’t know the Mk II very well, what does it record natively, interlaced/progressive, 720 or 1080?
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For clarification, it’s the Qmaster Node Installer that I was referring to, not Qmaster.
EULA: “Apple Qmaster Node Installer. The Apple Qmaster Software may be installed and used concurrently on as many Apple-labeled computers owned, leased, or otherwise controlled by you as reasonably necessary. These computers must be networked and running Mac OS X.”
https://www.apple.com/legal/sla/
Thanks Daniel.
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I have systems that encode ProRes that do not have FCP installed. After a bad night of sleep and sweating the legal ramifications of making a bad move, I have finally figured out what is going on…
Please note admins, I was not “trying” anything. This was an honest mistake.
We have 12 FCP seats in house and even more production computers that are tasked with playing and transcoding video with QT Pro. These production machines have always been able to produce ProRes video. After scouring the internet for ProRes legal info, I realized what was happening. These production machines are part of our render farm. There all loaded with Qmaster (no license needed) which installs the ProRes encoder!
So yes, the ProRes encoder comes with FCP. It does not come with FCP express or any other other retail product (as far as I know).
Again, my apologies to the board. I’m still looking for the ProRes encoder ULAs. If anyone has a link please post it. I’ll be sure to pass this info along to others in our market.
Thanks.
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Daniel,
I don’t disagree with your points, I’m just finding some end users who are still running CRTs and do not have progressive scan DVD players. Unless I know exactly where the content is going, I tend to play it safe so I do not double my work by having a client say, “this won’t play on my tv”.[Daniel Low] “Only if the DVD player is connected to a CRT TV that does not support progressive scan.”
Scan line decimation will also happen if your DVD player is not capable of outputting a progressive signal, i.e., 480i.
[Daniel Low] “So, what about all the HD tape formats? “
Fair enough, there are excellent SD and HD tape formats. I am fortunate enough that most of the workflows that I’m working with, from camera to display, are all tapeless. If I had my way, I’d have a fleet of HDCam SR decks!
[Daniel Low] “Certainly not the case in Europe. SD is interlaced but HD is a mixture of 720p and 1080i “
Isn’t 1080i interlaced? There is a large mix of 720p and 1080i footage here in the states, it’s predominately 1080i. My examples below are related to frame rates we have here in the states. 25 and 50 fps workflows and processing is probably a bit different.
I’m viewing this from the video processing side of the equipment and here’s what I see:
1. 24p footage has added pulldown for 1080i 60 broadcast. This is deinterlaced by the cable receiver or the TV depending on what the output of the receiver is set to (720p, 1080i, 1080p).
2. 720p can get caught up in processing if your cable receiver is set to 1080i. If you receiver is set for 1080i and you look at 720p, the 720p is upscaled and turned into 1080i, the TV will take the 1080i and pass the signal through a deinterlacer to display a progressive signal.
Even if we’re looking at 720p 60 material from a television station, wouldn’t their feature films have a pulldown applied to it to get it from 24p to 30i to 60p? Deinterlacing is happening somewhere.
There is a lot of hardware processing going on. These processors are high quality so this thread is probably a moot point in today’s world. Always deinterlacing may be a better way to go for 99% of applications but I’m a purist and I specify workflows based on the source media and what the media will be viewed on.
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I had no idea this was illegal in any form! I do not pirate software. I adhere to strict licensing guidelines but was misinformed about the ProRes Encoder.
I’ve removed this download and deeply apologize for the mistake.
Can you please point me towards the ProRes licensing information, I would greatly appreciate it.
Thanks.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
Don’t convert your progressive file to 1080i!!! There’s enough processing equipment in displays to wreak havoc on your video.
Just so we’re clear, you are running this MPEG Streamclip on a Mac, right?
This is the ProRes codec you need: (Link removed by site admins. Do NOT every try this again, Brian, or your account will be terminated.)
Just unzip it and put it in your Macintosh HD -> Library -> Quicktime folder.
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Brian Alexander
Sr Video Engineer
Freeman AVS -
I wouldn’t deinterlace the footage for a couple of reasons:
1. The existing hardware deinterlace processors are going to do less damage than software deinterlacing plus you save time in this step of the workflow.
2. Creating 30p (29.97) material on a DVD is going to introduce more artifacts by double (really triple) processing. Scan Line Decimation (480p -> 480i) then Scan Line Interpolation (480i -> 480p). (Scan line interpolation on LCD, Plasmas, Projectors; normal interlaced scan modes on CRT displays)
That said, here’s how I would troubleshoot the jaggies:
1. Make sure another DVD looks the same on the same monitor. You could be looking at poor processing in the monitor.
2. Scaling factors are different with different displays so your best bet would be to look at this DVD on your computer at it’s native resolution. Turn off the deinterlace filter if your using DVD Player, (OS X) this will show you true quality without all the processing.
3. Make sure the DVD player is setup correctly for your 16:9 or 4:3 display.
4. Make sure Zoom or Stretch or Fill is not enabled on the monitor.
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Brian Alexander
Sr Video Engineer
Freeman AVS