HDVxDV problem, plus slow motion sample at DVinfo.net

John Cordell · February 23rd, 2006, 12:21 AM

To anyone using HDVxDV, beware of some anomolous behavior I ran into...

I've been trying to do some slow motion footage by shooting 60i, converting to 60p, then conforming to 24fps. I was having trouble, and in the process realized that HDVxDV was apparently causing the trouble.

I found two problems:

1) When creating DVCPRO HD format, the order of the fields appears to be wrong (or at least different than the default that MPEG Streamclip generates). The effect was that the resulting 60p footage, when viewed frame by frame, would jump forward two frames, then back one, then forward two, etc. I fixed this problem by using MPEG Streamclip instead of HDVxDV for the conversion to 60p. (Though I was still using the .m2t file that HDVxDV had created upon capture.) But even then, I still had a problem...

2) The chroma info was out of sync by one frame in the 60p stream. Well, at least that's what it looks like, I don't know what really is happening. This was easy for me to notice because the footage was a moving basketball against a green background. I could see the orange outline of "where the ball will be in the next frame" on every single frame. I couldn't figure out how to get rid of this, but since I was capturing 60i footage, not the 24f I almost exclusively use, I realized I could just capture in FCP and cut HDVxDV completely out of the picture. So I did, and everything worked fine. It worked fine using both HDV capture and the HDV to AIC capture.

Sorry for the long story, but since I had mentioned HDVxDV on this forum before, I wanted to promptly report the problems that I was having.

Note that for 24f capture and normal playback of 60i material, I haven't noticed any problems using HDVxDV. Makes me wonder, though.

And finally, here's a link to a clip of some slow motion shot on the H1 in 1080 60i, converted to 60p, then conformed to 24fps. For fun, I shot this with a very fast shutter speed (about 1/800 i think) in order to see what slow motion without any motion blur would look like. It's 16MB for about 5 seconds of action, so enjoy if you're so inclined...

http://cordellproductions.com/movies/basketsm.mov

For the full bits (my PC barfed on this but the Mac likes it), at 62MB, you can get:

http://cordellproductions.com/movies...low motion.mov

Barlow Elton · February 23rd, 2006, 10:35 AM

Pretty cool, John. Did you resize the larger QT movie to 1920x1080? It did that Cinema Tools thing where it shows up as a smaller 640x360 movie, then you play it at "actual size" and boom! 1920x1080! Still looked pretty good at that frame size.

Overall a nice example, but it still looked a bit steppy for my tastes. Whaddya think the best shutter speed for the effect is? Did you see Holyzoo's HVX basketball footage? I loved that look...wonder what shutter speed he used to get that kind of slow motion?

Great job and keep 'em comin!

John Cordell · February 23rd, 2006, 11:52 AM

Agree, it was too 'steppy' for me too, just wanted to show people what high shutter slow motion looks like. I plan on experimenting with other shutter speeds. I think the optimal is when fast moving body parts get some motion blur but other parts stay nice and crisp. I will post any interesting results I find. I have a wide shot of me shooting baskets shot at normal shutter speed and the motion blur makes it work better.

Size: In order to stay at 1920x1080, in the compressor inspector, under geometry, I chose "frame size: 100% of original" and it kept it at 1920x1080.

Default size on QT open: For some reason when Cinema Tools conforms the clip to 23.98, it changes the "default" size to something like 1/4 original size. I've not looked into why that happens.

Barlow Elton · February 23rd, 2006, 12:30 PM

Quote:

Originally Posted by John Cordell

Size: In order to stay at 1920x1080, in the compressor inspector, under geometry, I chose "frame size: 100% of original" and it kept it at 1920x1080.

Wow, well now we have 1080p overcrank! Still looked pretty dang good to my eye. Sure it's a little softer, but wow, you can stay in 1080 and get a nice slo mo effect. This stuff just keeps getting better.

btw, either you're like me and like to play on 9ft hoops, or you need to go to the NBA big man's camp and work on your post moves, then try to defend Shaq! As Bill Walton would say (incessantly) "just throw it down, big man!!"

Barlow Elton · February 23rd, 2006, 12:39 PM

Forgot to ask you, John...what codec did you render to 1080? Just straight h.264 or did you go to another codec before rendering the h.264?

John Cordell · February 23rd, 2006, 01:04 PM

That hoop is adjustable, and was at 7.5 feet for that shot. I'm 6 feet tall, so I had to crouch down a bit to stay out of the shot! One idea I had for a short short was some close up "amazing dunking" followed by a single wide shot revealing the actual height of the basket.

The big file (62 MB) workflow:

1) shot 1080i
2) captured using FCP, plain ol' "HDV"
3) Compressor'ed to DVCPRO HD 720p60 (but frame size kept at 100% original)
4) Cinema Tools to conform to 23.98fps.

The small file (16MB) workflow:

5) took the file from above and used...
6) Compressor to convert to H.264 using menu choice "HD DVD: 60 minutes -> H.264 10.3Mbps".

Colin McFadden · February 27th, 2006, 04:27 PM

Could you walk through your workflow once more? I'm trying to duplicate it, but keep getting 60p video streams with lots of duplicate frames. So, whether I do it in streamclip or using compressor, it seems like I'm getting the 60i file, deinterlaced to 30p, then frame-doubled up to 60p, rather than getting the two fields from the 60i as discrete frames in the 60p file (which is what I want, and what I believe you've achieved).

Any help?

HDV timeline in FCP
File->export to compressor
DVCProHD 720p preset, 100% of original
Submit

When I step through the resulting file, I get frame, then duplicate frame, frame, duplicate frame, etc...

February 23rd, 2006, 12:21 AM	#1
John Cordell Regular Crew Join Date: Dec 2003 Location: Los Angeles, CA Posts: 69	HDVxDV problem, plus slow motion sample To anyone using HDVxDV, beware of some anomolous behavior I ran into... I've been trying to do some slow motion footage by shooting 60i, converting to 60p, then conforming to 24fps. I was having trouble, and in the process realized that HDVxDV was apparently causing the trouble. I found two problems: 1) When creating DVCPRO HD format, the order of the fields appears to be wrong (or at least different than the default that MPEG Streamclip generates). The effect was that the resulting 60p footage, when viewed frame by frame, would jump forward two frames, then back one, then forward two, etc. I fixed this problem by using MPEG Streamclip instead of HDVxDV for the conversion to 60p. (Though I was still using the .m2t file that HDVxDV had created upon capture.) But even then, I still had a problem... 2) The chroma info was out of sync by one frame in the 60p stream. Well, at least that's what it looks like, I don't know what really is happening. This was easy for me to notice because the footage was a moving basketball against a green background. I could see the orange outline of "where the ball will be in the next frame" on every single frame. I couldn't figure out how to get rid of this, but since I was capturing 60i footage, not the 24f I almost exclusively use, I realized I could just capture in FCP and cut HDVxDV completely out of the picture. So I did, and everything worked fine. It worked fine using both HDV capture and the HDV to AIC capture. Sorry for the long story, but since I had mentioned HDVxDV on this forum before, I wanted to promptly report the problems that I was having. Note that for 24f capture and normal playback of 60i material, I haven't noticed any problems using HDVxDV. Makes me wonder, though. And finally, here's a link to a clip of some slow motion shot on the H1 in 1080 60i, converted to 60p, then conformed to 24fps. For fun, I shot this with a very fast shutter speed (about 1/800 i think) in order to see what slow motion without any motion blur would look like. It's 16MB for about 5 seconds of action, so enjoy if you're so inclined... http://cordellproductions.com/movies/basketsm.mov For the full bits (my PC barfed on this but the Mac likes it), at 62MB, you can get: http://cordellproductions.com/movies...low motion.mov

February 27th, 2006, 04:27 PM	#7
Colin McFadden Sponsor: divergent media Join Date: Jun 2004 Location: St. Paul, MN Posts: 201	Could you walk through your workflow once more? I'm trying to duplicate it, but keep getting 60p video streams with lots of duplicate frames. So, whether I do it in streamclip or using compressor, it seems like I'm getting the 60i file, deinterlaced to 30p, then frame-doubled up to 60p, rather than getting the two fields from the 60i as discrete frames in the 60p file (which is what I want, and what I believe you've achieved). Any help? HDV timeline in FCP File->export to compressor DVCProHD 720p preset, 100% of original Submit When I step through the resulting file, I get frame, then duplicate frame, frame, duplicate frame, etc... __________________ Divergent Media Support www.divergentmedia.com

February 23rd, 2006, 10:35 AM	#2
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	Pretty cool, John. Did you resize the larger QT movie to 1920x1080? It did that Cinema Tools thing where it shows up as a smaller 640x360 movie, then you play it at "actual size" and boom! 1920x1080! Still looked pretty good at that frame size. Overall a nice example, but it still looked a bit steppy for my tastes. Whaddya think the best shutter speed for the effect is? Did you see Holyzoo's HVX basketball footage? I loved that look...wonder what shutter speed he used to get that kind of slow motion? Great job and keep 'em comin!

February 23rd, 2006, 11:52 AM	#3
John Cordell Regular Crew Join Date: Dec 2003 Location: Los Angeles, CA Posts: 69	Agree, it was too 'steppy' for me too, just wanted to show people what high shutter slow motion looks like. I plan on experimenting with other shutter speeds. I think the optimal is when fast moving body parts get some motion blur but other parts stay nice and crisp. I will post any interesting results I find. I have a wide shot of me shooting baskets shot at normal shutter speed and the motion blur makes it work better. Size: In order to stay at 1920x1080, in the compressor inspector, under geometry, I chose "frame size: 100% of original" and it kept it at 1920x1080. Default size on QT open: For some reason when Cinema Tools conforms the clip to 23.98, it changes the "default" size to something like 1/4 original size. I've not looked into why that happens.

February 23rd, 2006, 12:39 PM	#5
Barlow Elton Major Player Join Date: Mar 2005 Location: UT Posts: 945	Forgot to ask you, John...what codec did you render to 1080? Just straight h.264 or did you go to another codec before rendering the h.264?

February 23rd, 2006, 01:04 PM	#6
John Cordell Regular Crew Join Date: Dec 2003 Location: Los Angeles, CA Posts: 69	That hoop is adjustable, and was at 7.5 feet for that shot. I'm 6 feet tall, so I had to crouch down a bit to stay out of the shot! One idea I had for a short short was some close up "amazing dunking" followed by a single wide shot revealing the actual height of the basket. The big file (62 MB) workflow: 1) shot 1080i 2) captured using FCP, plain ol' "HDV" 3) Compressor'ed to DVCPRO HD 720p60 (but frame size kept at 100% original) 4) Cinema Tools to conform to 23.98fps. The small file (16MB) workflow: 5) took the file from above and used... 6) Compressor to convert to H.264 using menu choice "HD DVD: 60 minutes -> H.264 10.3Mbps".