HDV to SD downconversion

Michael Galvan · April 6th, 2006, 09:55 PM

Just want to clarify ...

Is my understanding correct in that shooting in 1080 HDV 24F, and then downconverting to SD with a lossless codec like PhotoJpeg at 100% with something like MPEG Streamclip, would essentially yield 4:4:4 SD video?

I'm thinking of doing this for an upcoming film competition, and will be shooting HDV, but the final delivery format will be DVD. So rather than shooting in the DV mode, in theory, shooting HDV and downconverting to SD with a better codec should provide superior results.

4:2:2 would be sufficient for this, so what codec would you recommend ... DVCPro50, PhotoJPEG (75%-100%), or Apple Uncompressed 4:2:2? I'll be working within Final Cut Pro.

Barlow Elton · April 6th, 2006, 09:57 PM

PhotoJPEG@100% is where it's at.

Simon Cooper · April 7th, 2006, 03:55 AM

Presumably you're considering this route for considerable post-tweaking or effects once it is SD? Is this a better route than shooting HDV, tweaking/FX in HDV, then either downsampling to SD via a NLE or even using the camera itself to downconvert?

Forgive me, I have nothing to add but I'm very curious about the pros and cons of the workflow you're choosing. I tend to do a lot of post effects work and I'm keen to know what tricks other people are using.

Si

Barlow Elton · April 7th, 2006, 08:53 AM

Personally, I think it's best to do it all in an HD format, then downconvert at the end.

He might be wanting to simplify things though for a speedier post process.
Although that's also fairly negligible, given a fast G5 or PC.

K. Forman · April 7th, 2006, 09:01 AM

Barlow- Just out of curiosity, what is your workflow?

Barlow Elton · April 7th, 2006, 09:13 AM

Workflow:

--Shoot HDV and occasionally straight to SDI
--Transcode via SDI or MPEG Streamclip to DVCProHD or PhotoJPEG@75%
--Inverse Telecine 24F clips in Cinema Tools (PITA, but I like true 24p timelines)
--Edit in FCP in either 1080 24p timelines, or standard 1080i
--Export finished QT movies in DVCProHD or PhotoJPEG
--Encode h.264 in 720 or 1080 for HD DVD
--Downconvert to DV50 or PhotoJPEG @100% for SD DVD encoding

Basically, HDV is acquisition only for me. This might change if and when Apple truly supports the H1, but I doubt I'll stop working in intermediate codecs. I think even with true 24p HDV timelines (for 24F stuff) it'll still be overly render heavy but I sure hope I'm wrong.

K. Forman · April 7th, 2006, 09:19 AM

Does that get you 4:2:2?

Barlow Elton · April 7th, 2006, 09:23 AM

Only raw SDI capture...but 4.2.0 from the H1 is plenty good for my needs.

Look at my extremely simple greenscreen shots. There are some uncompressed SDI frames, raw SDI to DVCProHD clips, and m2t's from tape transcoded back to DVCProHD and PhotoJPEG.

Tell me what you think?

www.homepage.mac.com/mrbarlowelton

K. Forman · April 7th, 2006, 09:39 AM

You are using PAL to get the 4:2:0 then? Just trying to follow along, because this is far different than the old DV stuff. I'm pretty well stuck with weak 4:1:1 as a source file, which certainly doesn't get any better when working on it. Now we have HDV available, and it is supposed to offer far better results, and higher chroma and color.

Barlow Elton · April 7th, 2006, 09:44 AM

HDV, in 50hz (PAL spec) or 60hz (NTSC spec) is 4.2.0 color sampling in a 1440x1080 frame. There's still a lot of chroma information and because the resolution is so high, I believe there's a lot more to work with than the SD formats.

I'm not using PAL, I have a 60hz H1.

Simon Cooper · April 7th, 2006, 09:45 AM

Thanks for the info, Barlow.

Si

K. Forman · April 7th, 2006, 09:46 AM

Ok, gotcha now. Thanks :)

Robert Sanders · April 7th, 2006, 10:36 AM

Barlow - you are the man.

Barlow Elton · April 7th, 2006, 10:57 AM

Quote:

Originally Posted by Robert Sanders

Barlow - you are the man.

Right back atcha! :-)

...jus keepin' it real.

Michael Galvan · April 7th, 2006, 01:32 PM

Thanks for all your responses. I'm particulalry interested in this, because the final output for this competition will be dvd. In this case, I will shoot HDV, but am planning to do my edit in SD (capture 24F HDV and convert to most likely DVCPro50 or PhotoJPEG (100%) at this point). Since this is a 48 hour film competition, time is of the essence, and I would rather edit in SD to save processing power (despite the fact that I have a G5 Quad).

I also plan to do some heavy color correcting/effects to some of the shots, hence my interest in bringing it to 4:2:2 or 4:4:4 SD. So that's why I just wanted some confirmation on whether HDV 4:2:0 when downconverted to something like DV50 or PhotoJPEG really yields a true 4:2:2 or 4:4:4 SD file. I'm not so much interested in an HD master, as I will need the SD DVD to look the best it can. This is why I am choosing to convert to SD before doing my editing and color correction - for both time and final DVD quality.

I did some quick tests, and I notice that DVCPro50 footage renders about twice as fast as PhotoJPEG(100%) footage, after applying some filter sets. Although, I'd like to try PhotoJPEG for this, I think DV50 may be better in this scenario because of the time restraints to the competition. Thoughts?

April 6th, 2006, 09:55 PM	#1
Michael Galvan Major Player Join Date: Sep 2004 Location: New York, NY Posts: 775	HDV to SD downconversion - chroma sampling Just want to clarify ... Is my understanding correct in that shooting in 1080 HDV 24F, and then downconverting to SD with a lossless codec like PhotoJpeg at 100% with something like MPEG Streamclip, would essentially yield 4:4:4 SD video? I'm thinking of doing this for an upcoming film competition, and will be shooting HDV, but the final delivery format will be DVD. So rather than shooting in the DV mode, in theory, shooting HDV and downconverting to SD with a better codec should provide superior results. 4:2:2 would be sufficient for this, so what codec would you recommend ... DVCPro50, PhotoJPEG (75%-100%), or Apple Uncompressed 4:2:2? I'll be working within Final Cut Pro. __________________ www.michaelgalvan.com www.screenanthology.com

April 7th, 2006, 03:55 AM	#3
Simon Cooper New Boot Join Date: May 2004 Location: Southampton, Hants, UK Posts: 10	Presumably you're considering this route for considerable post-tweaking or effects once it is SD? Is this a better route than shooting HDV, tweaking/FX in HDV, then either downsampling to SD via a NLE or even using the camera itself to downconvert? Forgive me, I have nothing to add but I'm very curious about the pros and cons of the workflow you're choosing. I tend to do a lot of post effects work and I'm keen to know what tricks other people are using. Si __________________ Canon XL H1, Premiere Pro, After Effects and a twisted sense of humour. www.wholehogfilms.com

April 7th, 2006, 09:01 AM	#5
K. Forman Capt. Quirk Join Date: Apr 2002 Location: Middle of the woods in Georgia Posts: 3,596	Barlow- Just out of curiosity, what is your workflow? __________________ www.SmokeWagonLeather.us

April 7th, 2006, 09:19 AM	#7
K. Forman Capt. Quirk Join Date: Apr 2002 Location: Middle of the woods in Georgia Posts: 3,596	Does that get you 4:2:2? __________________ www.SmokeWagonLeather.us

April 7th, 2006, 09:39 AM	#9
K. Forman Capt. Quirk Join Date: Apr 2002 Location: Middle of the woods in Georgia Posts: 3,596	You are using PAL to get the 4:2:0 then? Just trying to follow along, because this is far different than the old DV stuff. I'm pretty well stuck with weak 4:1:1 as a source file, which certainly doesn't get any better when working on it. Now we have HDV available, and it is supposed to offer far better results, and higher chroma and color. __________________ www.SmokeWagonLeather.us

April 6th, 2006, 09:57 PM	#2
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	PhotoJPEG@100% is where it's at.

April 7th, 2006, 08:53 AM	#4
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	Personally, I think it's best to do it all in an HD format, then downconvert at the end. He might be wanting to simplify things though for a speedier post process. Although that's also fairly negligible, given a fast G5 or PC.

April 7th, 2006, 09:13 AM	#6
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	Workflow: --Shoot HDV and occasionally straight to SDI --Transcode via SDI or MPEG Streamclip to DVCProHD or PhotoJPEG@75% --Inverse Telecine 24F clips in Cinema Tools (PITA, but I like true 24p timelines) --Edit in FCP in either 1080 24p timelines, or standard 1080i --Export finished QT movies in DVCProHD or PhotoJPEG --Encode h.264 in 720 or 1080 for HD DVD --Downconvert to DV50 or PhotoJPEG @100% for SD DVD encoding Basically, HDV is acquisition only for me. This might change if and when Apple truly supports the H1, but I doubt I'll stop working in intermediate codecs. I think even with true 24p HDV timelines (for 24F stuff) it'll still be overly render heavy but I sure hope I'm wrong.

April 7th, 2006, 09:23 AM	#8
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	Only raw SDI capture...but 4.2.0 from the H1 is plenty good for my needs. Look at my extremely simple greenscreen shots. There are some uncompressed SDI frames, raw SDI to DVCProHD clips, and m2t's from tape transcoded back to DVCProHD and PhotoJPEG. Tell me what you think? www.homepage.mac.com/mrbarlowelton

April 7th, 2006, 09:44 AM	#10
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	HDV, in 50hz (PAL spec) or 60hz (NTSC spec) is 4.2.0 color sampling in a 1440x1080 frame. There's still a lot of chroma information and because the resolution is so high, I believe there's a lot more to work with than the SD formats. I'm not using PAL, I have a 60hz H1.

April 7th, 2006, 09:45 AM	#11
Simon Cooper New Boot Join Date: May 2004 Location: Southampton, Hants, UK Posts: 10	Thanks for the info, Barlow. Si __________________ Canon XL H1, Premiere Pro, After Effects and a twisted sense of humour. www.wholehogfilms.com

April 7th, 2006, 09:46 AM	#12
K. Forman Capt. Quirk Join Date: Apr 2002 Location: Middle of the woods in Georgia Posts: 3,596	Ok, gotcha now. Thanks :) __________________ www.SmokeWagonLeather.us

April 7th, 2006, 10:36 AM	#13
Robert Sanders Starway Pictures Join Date: Jul 2005 Location: Studio City Posts: 581	Barlow - you are the man. __________________ http://www.starwaypictures.com http://starwaypictures.blogspot.com/

April 7th, 2006, 01:32 PM	#15
Michael Galvan Major Player Join Date: Sep 2004 Location: New York, NY Posts: 775	Thanks for all your responses. I'm particulalry interested in this, because the final output for this competition will be dvd. In this case, I will shoot HDV, but am planning to do my edit in SD (capture 24F HDV and convert to most likely DVCPro50 or PhotoJPEG (100%) at this point). Since this is a 48 hour film competition, time is of the essence, and I would rather edit in SD to save processing power (despite the fact that I have a G5 Quad). I also plan to do some heavy color correcting/effects to some of the shots, hence my interest in bringing it to 4:2:2 or 4:4:4 SD. So that's why I just wanted some confirmation on whether HDV 4:2:0 when downconverted to something like DV50 or PhotoJPEG really yields a true 4:2:2 or 4:4:4 SD file. I'm not so much interested in an HD master, as I will need the SD DVD to look the best it can. This is why I am choosing to convert to SD before doing my editing and color correction - for both time and final DVD quality. I did some quick tests, and I notice that DVCPro50 footage renders about twice as fast as PhotoJPEG(100%) footage, after applying some filter sets. Although, I'd like to try PhotoJPEG for this, I think DV50 may be better in this scenario because of the time restraints to the competition. Thoughts? __________________ www.michaelgalvan.com www.screenanthology.com