Now I'm Really Confused: HDV capture using DVCPRO HD? at DVinfo.net

Meryem Ersoz · May 20th, 2007, 07:58 PM

i'm looking to maximize my HDV workflow. basically, i'm been losing my mind with the long render times (on my laptop, the tower does fine...) capturing HDV into an HDV timeline. AIC has its own issues explored in other threads.

i just read an article where the author suggests capturing HDV footage into FCP (this workflow does not require a specialized capture card) and then transcoding through Compressor into DVPRO HD. he says the advantages are that it handles motion better, renders much faster, and has the 4:2:2 (versus 4:2:0 of HDV) colorspace.

now this is what confuses me. can transcoding actually enhance color space? i understand how up-rez/down-rez can offer enhancements, but isn't the color space fixed by what is on the tape?

is anyone else using this HDV capture to DVPRO HD via Compressor workflow, who is able to comment on their experiences?

James Miller · May 21st, 2007, 12:59 AM

Hi Meryem,

I have all the popular presets and agree that DVCPRO does handle fast motion better and the colour space does has more latitude for adjustment.

Transcoding from HDV did not show as much advantage as transcoding from raw captured .m2t files. But coming from .m2t requires demuxing first otherwise compressor will not open it.

I would try a few tests on a 1min clip that includes some strong colours and fast motion. And find the best workflow suited to each of your computers.

Meryem Ersoz · May 21st, 2007, 06:40 AM

i definitely plan to do a few quick tests. i'm mostly curious about whether the color space actually changes from a 4:2:0 to a 4:2:2--i realize latitude could be altered but doesn't this actually imply adding color?

i did read about your workflow on another thread, m2t via DVHscap to mpegstreamclip. i have mpegstreamclip, and it's a great program, very fast and clean, so it would probably not add much time to the workflow. but i have not tried the other program. isn't it a beta tester or something?

i'll take a whack at some testing of my own, unless i hear from some others. my studio just made the shift to all-HDV, all the time, and we are encountering some workflow bumps.

Gene Crucean · May 21st, 2007, 07:10 AM

It shouldn't increase quality. Compare it to up-rezzing SD to HD, you have HD with SD quality. DVCPRO HD has better capabilities but as far as I know (I'd love to be proven wrong) it will not give you better quality than HDV. Although if you keep your entire workflow in DVCPRO then other post processes will benefit from the higher sampling and better compression.

$0.02

James Miller · May 21st, 2007, 09:39 AM

Gene, If you compare a clip captured in FCP using the apple HDV codec and then the same clip captured in DVHSCap and transcoded into an intermediate codec like AIC or DVCPRO HD, there is a difference.
I will have to post some frame grabs to put my point across.

Meryem Ersoz · May 21st, 2007, 09:40 AM

some frame grabs would be awesome, thanks! i'll still run my own tests, but a visual would be super helpful.

Dick Nelson · May 21st, 2007, 09:56 AM

DVHS cap is part of the "FireWire SDK 23 for Mac OS X" download, and is available free at <http://developer.apple.com/hardwaredrivers/download/>
You will need an Apple ID, and to agree to the software terms.

In terms of thinking of color space changes from HDV to any of the 4:2:2 color spaces, try this: Draw a triangle on a piece of paper. Then draw another, slightly larger triange overlapping and surrounding the first. The inner triange is your HDV color space, the larger one the larger color space of the other codec. You'll have more room to make corrections, a greater number of possible hue, saturation, and luma values. If you later downconvert back to HDV for output, the downconversion will shrink your color space back to the original triangle, but the individual color choices that remain will be slightly different and have fewer artifacts than if you had remained in HDV land. At least that's my understanding of the issues. I'm still a newbie at HDV myself.

James Miller · May 21st, 2007, 01:03 PM

Quote:

Originally Posted by Meryem Ersoz

some frame grabs would be awesome, thanks! i'll still run my own tests, but a visual would be super helpful.

Codec Screen Grabs- The folder is a bit of a mess but on the top of the grab the quicktime window show the file names.

http://www.millermiller.co.uk/dvinfo

100% frame sizes
HDV - AIC (8 examples)
PRORES SQ - AIC (1 example)
HDV - DVCPRO (3 examples)

Files in PNG format (standard mac screen grab)

I Note:

• Apple captures HDV at 1888 x 1062 thus cropping the image just a little.

• ProRes looks very dull in colour next to DVCPRO.

• DVCPRO matches HDV the closest.

• Apple AIC is the sharpest, but less forgiving for shots with a lot of gain.

If you put a .m2t demuxed as an m2v through Apple Compressor using AIC or DVCPRO make sure the size is 1440 x 1080 square, and let FCP do the stretching. Otherwise the results are poor, and take much longer to transcode.

If you can't figure the files out, give me the picture name and I will tell you what it is.

May 20th, 2007, 07:58 PM	#1
Meryem Ersoz Wrangler Join Date: Jan 2005 Location: Boulder, CO Posts: 3,015	Now I'm Really Confused: HDV capture using DVCPRO HD? i'm looking to maximize my HDV workflow. basically, i'm been losing my mind with the long render times (on my laptop, the tower does fine...) capturing HDV into an HDV timeline. AIC has its own issues explored in other threads. i just read an article where the author suggests capturing HDV footage into FCP (this workflow does not require a specialized capture card) and then transcoding through Compressor into DVPRO HD. he says the advantages are that it handles motion better, renders much faster, and has the 4:2:2 (versus 4:2:0 of HDV) colorspace. now this is what confuses me. can transcoding actually enhance color space? i understand how up-rez/down-rez can offer enhancements, but isn't the color space fixed by what is on the tape? is anyone else using this HDV capture to DVPRO HD via Compressor workflow, who is able to comment on their experiences?

May 21st, 2007, 12:59 AM	#2
James Miller Major Player Join Date: Mar 2007 Location: Sussex, UK Posts: 317	Hi Meryem, I have all the popular presets and agree that DVCPRO does handle fast motion better and the colour space does has more latitude for adjustment. Transcoding from HDV did not show as much advantage as transcoding from raw captured .m2t files. But coming from .m2t requires demuxing first otherwise compressor will not open it. I would try a few tests on a 1min clip that includes some strong colours and fast motion. And find the best workflow suited to each of your computers.

May 21st, 2007, 06:40 AM	#3
Meryem Ersoz Wrangler Join Date: Jan 2005 Location: Boulder, CO Posts: 3,015	i definitely plan to do a few quick tests. i'm mostly curious about whether the color space actually changes from a 4:2:0 to a 4:2:2--i realize latitude could be altered but doesn't this actually imply adding color? i did read about your workflow on another thread, m2t via DVHscap to mpegstreamclip. i have mpegstreamclip, and it's a great program, very fast and clean, so it would probably not add much time to the workflow. but i have not tried the other program. isn't it a beta tester or something? i'll take a whack at some testing of my own, unless i hear from some others. my studio just made the shift to all-HDV, all the time, and we are encountering some workflow bumps.

May 21st, 2007, 07:10 AM	#4
Gene Crucean Major Player Join Date: Mar 2006 Location: Los Angeles, CA Posts: 295	It shouldn't increase quality. Compare it to up-rezzing SD to HD, you have HD with SD quality. DVCPRO HD has better capabilities but as far as I know (I'd love to be proven wrong) it will not give you better quality than HDV. Although if you keep your entire workflow in DVCPRO then other post processes will benefit from the higher sampling and better compression. $0.02

May 21st, 2007, 09:39 AM	#5
James Miller Major Player Join Date: Mar 2007 Location: Sussex, UK Posts: 317	Gene, If you compare a clip captured in FCP using the apple HDV codec and then the same clip captured in DVHSCap and transcoded into an intermediate codec like AIC or DVCPRO HD, there is a difference. I will have to post some frame grabs to put my point across.

May 21st, 2007, 09:40 AM	#6
Meryem Ersoz Wrangler Join Date: Jan 2005 Location: Boulder, CO Posts: 3,015	some frame grabs would be awesome, thanks! i'll still run my own tests, but a visual would be super helpful.

May 21st, 2007, 09:56 AM	#7
Dick Nelson Regular Crew Join Date: Aug 2006 Location: Silverthorne, CO Posts: 36	DVHS cap is part of the "FireWire SDK 23 for Mac OS X" download, and is available free at <http://developer.apple.com/hardwaredrivers/download/> You will need an Apple ID, and to agree to the software terms. In terms of thinking of color space changes from HDV to any of the 4:2:2 color spaces, try this: Draw a triangle on a piece of paper. Then draw another, slightly larger triange overlapping and surrounding the first. The inner triange is your HDV color space, the larger one the larger color space of the other codec. You'll have more room to make corrections, a greater number of possible hue, saturation, and luma values. If you later downconvert back to HDV for output, the downconversion will shrink your color space back to the original triangle, but the individual color choices that remain will be slightly different and have fewer artifacts than if you had remained in HDV land. At least that's my understanding of the issues. I'm still a newbie at HDV myself.