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HD-SD conversions still unsolved
I have yet to get a handle on a good method to down convert HD material to SD for broadcast.
Lately, I’ve been shooting on an HPX-500 (usually 720p 60) and editing it in FCP with a matching sequence and then converting it to NTSC 4:3 letterbox 29.97 via Blackmagic Multibridge Pro on output. In my experience that gets better results than converting it in FCP. But it is still looks bad. and now a client of ours is calling us out. “Aliasing, pixelized, jumpy”
I fully convinced that I’m missing something elemental!
Any assistance would be greatly appreciated.
sean schiavolin
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10 Replies
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Might not be the answer you want, but the AJA Kona boards output pristine SD downconversion from any HD timeline. We do this all the time for broadcast.
Also 720 to 1080i cross conversions all the time for HD broadcast.
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!
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Which video monitor are you monitoring the image on? Or is it the computer monitor?
Kevin Monahan
fcpworld.com
Author – Motion Grahpics and Effects in Final Cut Pro
Now seeking post-production work in Los Angeles -
thanks Walter. what’s their secret?
have you found any other proven methods?
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well…that’s a good question. I’m outputting straight from the multibridge pro via HDMI to a 46″ Vizio LCD HD monitor. Up until the client complained I reasoned that it was the monitor and the lack of a proper NTSC monitor (which would ultimately reveal that it looked fine) But I guess I was wrong.
and of course the computer monitor looks great playing the SD.
Got an idea of what I need to do?
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[Sean Schiavolin] “thanks Walter. what’s their secret?
have you found any other proven methods?”
AJA is a broadcast centric company and their equipment has been used for years in live events and high end broadcast. You don’t do that unless your products are very very good. Their products are solid and built specifically for the broadcast industry to their specs, not put together from off the shelf parts. That’s why AJA products can do so much in realtime.
Not only HD to SD downconversion, but with the Kona 3 for example I have three outputs. In one pass I can assign Output 1 to play the native HD from the timeline, let’s say 720p, Output 2 can be assigned to downconvert to SD, Output 3 can be assigned to output the 720p converted to 1080i. All in full broadcast quality realtime.
[Sean Schiavolin] “have you found any other proven methods?”
Nothing that I would ever allow my projects to go out with, and there’s no reason for me to even research other methods. That’s why I purchased the Konas. Why waste time trying to figure out what will render the best quality when we can just do this in realtime?
Walter Biscardi, Jr.
Biscardi Creative Media
HD and SD Production for Broadcast and Independent Productions.STOP STARING AND START GRADING WITH APPLE COLOR Apple Color Training DVD available now!
Read my Blog!
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OK, I’ll add my 2 cents (or pennies). I know Walter loves AJA, and they are undoubtedly the Rolls Royce of cards, but it ain’t your Multibridge that’s making your video look cruddy.
If it looks OK on the comuter monitor, then I’d wager your HD monitor is making a bad job of converting. You seem to say you’re downconverting HD to SD, out of the HDMI, in to an HD46″ monitor, and its looking bad – well yeah, it will!! Most HD LCDs do a crappy job at best of upscaling SD to HD.
You need to hook a SD TV to your BM MBPro. Even composite will give you a better idea of any nasties like interlacing issues. Ideally use component to a decent monitor. If it’s still crappy then, make sure ALL your settings are OK. I’ve used my MBPro to downconvert HD to PAL SD and the quality has been more than fine.
HTH
Jason
_________________________________
Before you criticise a man, walk a mile in his shoes.
Then when you do criticise him, you’ll be a mile away. And have his shoes.*the artist formally known as Jaymags*
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[Jason Porthouse] “OK, I’ll add my 2 cents (or pennies). I know Walter loves AJA, and they are undoubtedly the Rolls Royce of cards, but it ain’t your Multibridge that’s making your video look cruddy.”
I second that, but I can tell exactly what the problem is.
The multibridge (I own one) only does software downconversion with 720. 1080i is done in hardware and looks MUCH better. It actually looks Perfect. This has been my only pet peeve with the black magic product. I don’t know why it will only downconvert 720 in software but they need to remedy that because its useless, producing aliased terrible offline looking video.
This is what I do, export your timeline to a quicktime file and downconvert it with compressor. Set the resize filter to best quality (you may have to make a copy of an apple preset to make that change)
This will create a Perfect SD down conversion every bit as worthy as the hardware down conversion.
This is your only real option.
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Chris, thank you very much for the helpful and practical info.
Too bad about Blackmagic. Do you know if it does a hardware down conversion with 1080p as opposed to 1080i?
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[Sean Schiavolin] “Too bad about Blackmagic. Do you know if it does a hardware down conversion with 1080p as opposed to 1080i?”
yeah its really frustrating because over emails and their forum here they NEVER answer my question when asked about 720 hardware downconversion.
any type of 1080 interlaced or progressive will downconvert in hardware.
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I have a Decklink HD PRO card and the downconverts from 1080 50i to SD are not great. Recently I compared the card, a nested re-render in an SD uncompressed timeline and the output of an HDW 1800 SD downconvert. The image quality of the HDW 1800 deck downconvert was a clear winner, with the software re render coming in second and the Decklink third.
All were checked on a variety of monitors from a 1080 Sharp Aquos LCD (45″) to a 14″ Sony CRT Broadcast monitor. Clearly on all monitors, the HDW1800 was the best. As I generally work with HDV or HDCam docos, the simple thing is to output to HDCam and crash record the digi beta at the same time.
That said, I am also specing a new system and the Kona 3 is the preferred interface at this stage.
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