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what’s better sdi or firewire?
Is it better, the same, or worse to digitize using the dvcprohd codec through the Kona card as opposed to firewire? Logistically it’s simpler to just run it through the sdi connector but is the signal transcoded to hd-sdi in the deck and transcoded back to dvcprohd in the card? Doesn’t this dual transcoding cycle cause wear and tear on your virgin digits?
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23 Replies
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[dan luke] “Is it better, the same, or worse to digitize using the dvcprohd codec through the Kona card as opposed to firewire? Logistically it’s simpler to just run it through the sdi connector but is the signal transcoded to hd-sdi in the deck and transcoded back to dvcprohd in the card? Doesn’t this dual transcoding cycle cause wear and tear on your virgin digits?”
For straight DVCPro HD, just come in and out via Firewire. If you come in HD-SDI, then come in uncompressed. Do not set up your Kona 2 to capture at DVCPro HD via the SDI input because that will simply add another round of DVCPro HD compression.
I’ve found that capturing DVCPro HD via Firewire and Uncompressed via HD-SDI yield identical capture results. There is no difference in picture quality. Some folks have a problem with editing in a DVCPro HD timeline due to the compression hit you will take with all the renders. To my eye, I’m not seeing a quality hit from the original so on this current project I’m working on, all 7 episodes are being captured Firewire, edited in DVCPro HD with filters, then output back via Firewire to DVCPro HD.
Walter Biscardi, Jr.
Creative Genius, Biscardi Creative Media
https://www.biscardicreative.comNow in Production, “The Rough Cut,” https://www.theroughcutmovie.com
“I reject your reality and substitute my own!” – Adam Savage, Mythbusters
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One place to really see these tests results is on Graeme Natress’s website. He did an extensive test to see just what the differences were.
this is the article.
https://www.nattress.com/Chroma_Investigation/chromasampling.htm
he did a demo of this at our FCP user group a few months back. He makes some of the most useful products for FCP.
David
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We have done our own little eye to eye testing and we agree with Graeme Natress, DV sources ingested via SDI and (saved as uncompressed 8/10bit ) looks better than DV sources injested via FireWire. But of course the SDI files are much larger.
However, we also believe the SDI/HDI into the KONA2 and down sampled to DV25, DV50, or DV100 “looks” the same as FireWire in of the same sources. We test this with a Panasonic HD1200A that had both the FireWIre and SDI/HDI options installed. We tried it with DV25, DV50 and DVCPRHD (DV100). We could not detect a difference in the Decompressed HDI -> Recompressed DVCPRO and the FireWire -> DVCPRO direct.
Fred
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[Fred Connors Jr] “However, we also believe the SDI/HDI into the KONA2 and down sampled to DV25, DV50, or DV100 “looks” the same as FireWire in of the same sources. We test this with a Panasonic HD1200A that had both the FireWIre and SDI/HDI options installed. We tried it with DV25, DV50 and DVCPRHD (DV100). We could not detect a difference in the Decompressed HDI -> Recompressed DVCPRO and the FireWire -> DVCPRO direct.”
Actually, you should be able to see a difference using that method since you’ve doubled the compression. You take a DVCPro HD tape which is already compressed. Run it into the Kona 2 and ask it to compress it again. I can see the added artifacts when viewing an image that has been captured this way.
If you’re going to come in HD-SDI, then stay at 720 uncompressed, don’t apply the DVCPro HD codec. I’ve done the side by side comparison of Firewire DVCPro HD capture vs. HD-SDI Uncompressed capture of a DVCPro HD tape and they are identical. But apply the DVCPro HD codec to the HD-SDI capture and there’s a difference.
Walter Biscardi, Jr.
Creative Genius, Biscardi Creative Media
https://www.biscardicreative.comNow in Production, “The Rough Cut,” https://www.theroughcutmovie.com
“I reject your reality and substitute my own!” – Adam Savage, Mythbusters
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“Actually, you should be able to see a difference using that method since you’ve doubled the compression. You take a DVCPro HD tape which is already compressed. Run it into the Kona 2 and ask it to compress it again. I can see the added artifacts when viewing an image that has been captured this way.”
“If you’re going to come in HD-SDI, then stay at 720 uncompressed, don’t apply the DVCPro HD codec. I’ve done the side by side comparison of Firewire DVCPro HD capture vs. HD-SDI Uncompressed capture of a DVCPro HD tape and they are identical. But apply the DVCPro HD codec to the HD-SDI capture and there’s a difference.”
Walter, I respectfully disagree:
The Firewire DVCPro HD capture vs. HD-SDI Uncompressed capture of a DVCPro HD tape are not identical. The Uncompessed HD-SDI of a DVCPro HD tape is better than the FireWire output of the same tape. We’ve done split screens of both and the 720 Uncompressed looks better than the DVCPro HD. The Graeme Natress article supports this although in SD vs DV25 only.
https://www.nattress.com/Chroma_Investigation/chromasampling.htm
It is our observation that the Uncompessed HD-SDI image from a DVCPro HD tape (Panasonic 1200A) is in fact better than the same image from the FireWire out of the same VTR. Thus allowing the second compression back to DVCPro HD thru the KONA-2, resulting in an image as good, but not better than, the image that came in from FireWire.
We did these test to justify purchasing the FieWire option in the Panasion deck. We could not prove that the option was needed if we had theHD-SDI to KONA path.
Fred
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All I can say is we’ve done splits here as well and honestly, there really is no way the HD-SDI capture could look better than firewire since it’s just digital information coming in. What you will see is if you start to add filters, the quality will be different in the uncompressed timeline, but again,t that depends on how many filters and what type.
We’ve done a split of a DVCPro HD Firewire Capture, DVCPro via HD-SDI at uncompressed and an AVID DS/HD capture of DVCPro via HD-SDI and in all cases, the captured video looked identical.
Comparing DV/25 vs. 8bit and DVCPro HD / 720 Uncompressed are not the same at all. It’s really an apples and oranges comparison since there’s a huge difference between DV/25 and DVCPro HD. With straight DV footage, you always want to work in uncompressed so your graphics don’t take a bit quality hit. With DVCPro HD, that’s not the case. I’m also finding that the filters hold up very well with DVCPro HD. It just depends on what you’re doing which will determine whether you want to go Firewire or Uncompressed on the way in.
Walter Biscardi, Jr.
Creative Genius, Biscardi Creative Media
https://www.biscardicreative.comNow in Production, “The Rough Cut,” https://www.theroughcutmovie.com
“I reject your reality and substitute my own!” – Adam Savage, Mythbusters
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Regarding Dan
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This has been a very good thread and many of the same questions that have come up in SD are not much different in HD. Each has a specific workflow and this makes perfect sense.
Robert. The footage looks better via HD SDI because you are capturing more information when you are capturing the DVCPRO at 8 or 10 bit uncompressed quality. But the source never gets better. It can only remain better throuhg the post process and I think that is always the fundamental arguement. The 10-bit uncompressed codecs will hold up better when rendering, importing motion graphics, and multigenerational codec performance. With DVCPRO HD100 you are looking at 14mb/sec file size and a frame that is 1280×1080 vs1920x1080. In uncompressed 10 bit that frame is always 1920×1080 with a data rate of 165MB/sec. That is almost ten times the data rate in the frame. This is why sony has developed SR, to put more information on the tape, which means more information can be captured. If these data rates and sizes did not matter, people would not be trying to capture 4:4:4 for truer color reproduction, etc. There is always going to be a push to crunch the most number of pixels from a through a lens to a CCD and onto tape then into our edit systems.
The question is always this. If you capture DVCPRO100 natively and send it out the Kona a the end of the day are you actually getting a worse picture because of the frame size and data rate? It will never get better that the amount of original information you have captured. But maybe that information is preserved better in the 10-bit uncompressed codec.
Now in HD, you may not see the difference on an 800 line CRT, but you might see the differnece if the tape you output was projected. nIt is also a fair argument to say, why capture more than I ever recorded. All of these choices come down to anyone persons specific workflow. So in Walters case that workflow is perfect for him and it is diiferent for Fred and Robert. IN the past with DV timelines I have cut the DV natively, created all of the graphics in Annimation codec and re-rendered my final sequence in 10 Bit uncompressed SD so that my graphics didn’t take the DV hit. It was a great compromise, using the low data rates and never recapturing, only recompressing (which quicktime is fantastic at!)
I think that if you can offline in DCVPRo100 and online (recapture) that finished product in 10-bit uncompressed you will have the best of both worlds, cutting at HD resoltion and finishing as good as it can possibly look.
It’s hard to argue about how something looks to the eye because it is subjective. 16mm film had a much better archival quality than 3/4inch video tape, but economics won. The worlds archive of events like the fall of the berlin wall, Tienimen Square, is a betacam tape. Compare that to how some re-released hollywood movies look on DVD, where great care was taken to capture the highest quality 35mm film and I guess that is why this sort of discussion will always be alive and well.
10-bit uncompressed is always only going to capture what is there as will the DVCPRO100 codec, but it is hard to argue that DVCPRO100 will hold up better multi-generationally than Uncompressed 10 bit HD.
Great thread!
David
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Hi – I will put my 2 cents in, in a different light.
If you are incorporating this into a facility, into a machine room, there is no question – you are going to use HD SDI, and not firewire, just like every other professional does
in a facility enviornment. If you are a home user, and want to get away with low costs, just stick your firewire cable in, and away you go. But this approach does not work in larger enviornments, where you must share a single HD VTR between several FCP HD edit suites, as well as dubbing, etc (as well as use of other VTR’s with your FCP HD system).
You will never see a professional facility using anything other than HDSDI, with RS422 control. If you are a news reporter in the field, or a student,or on a very low budget,
firewire will work for you.Bob Zelin
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Excellent points David.
There’s one other thing to consider in all of this. The settings on the Varicam during production. Those who have tested this camera will note that the Video Gamma settings are definitely cleaner than the Film Gamma settings. Film Gamma adds more noticeable noise to an image than Video Gamma.
So when deciding whether to go Uncompressed for your workflow or DVCPro HD, you need to consider how the project was shot. If it was shot with the Video Gamma settings, then the DVCPro HD workflow will add more noticeable noise as you add filters, renders, etc….
If it was shot in the Film Gamma settings, it’s very difficult, if not impossible to notice any additional noise or compression generated by the DVCPro HD workflow.
This is something you can see visually just by creating some split screens within FCP. One thing is for certain, working in the DVCPro HD codec is a very clean format and definitely nothing like working in the DV25 SD format. I’ve noticed that my animations and graphics created in After Effects are completely pristine rendered to the DVCPro HD codec.
One other thing is for certain whether you’re talking DVCPro HD or any HD production. Ask 25 people the same HD question and you’ll get 25 answers. It’s a true learning experience for everyone.
Walter Biscardi, Jr.
Creative Genius, Biscardi Creative Media
https://www.biscardicreative.comNow in Production, “The Rough Cut,” https://www.theroughcutmovie.com
“I reject your reality and substitute my own!” – Adam Savage, Mythbusters
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