Turning HD 720p into 4:3

[Daniel Kleinfeld]

Hi everyone!

I'm confronting a specific and strange question, but one that's got me stumped---hoping someone out there has a clever solution.

We're preparing footage for a client's online streaming broadcast, The material was shot in HD 720p59.94, and edited in Final Cut Pro using the DVCPro HD codec.

The client ultimately wants to do the Flash compression themselves. But they would like us to deliver the files as Quicktime movies for them to compress.

Here comes the tricky part: They are insistent on having the Quicktime files be 4:3, rather than the 16:9 of HD. But they also want them to be at the maximum resolution possible, which means as large as possible (hence just dropping the edited sequence into a 640 x 480 sequence and shrinking it down isn't an option).

We've tried a great deal of futzing with frame size and pixel aspect ratio, all to no avail---either the frame is visibly 16:9 (much wider than tall) or the picture is badly distorted. But it seems like there must be a way to get the same kind of large frame we have when exporting HD, but with the sides cut off---that's really all we need.

Does anyone have any ideas how we can do this? Thank you all in advance!

Daniel

[David Tamés]

The way I do this is as follows: (1) Export DVCPRO HD Master (16x9) from Final Cut using QuickTime Export; and then (2) Using Compressor, I convert the DVCPRO HD Master (16x9) file to a DV SD (4x3) file with the left and right edge cropped off using a custom made setting. This is the easiest way to create a cropped 4x3 DV master QuickTime file from a 16x9 DVCPRO HD master QuickTime file.

I created a custom Compressor setting to crop off the left and right sides of the 16x9 frame to end up with a 4x3 DV frame, starting off with the existing setting in "Other Workflows -> Advanced Format Conversion -> DV NTSC" and changed the Geometry setting (in the Inspector) so that "Source Insert (cropping)" is set to "Crop to: 4x3" and then did a "Save As" and gave it a name like "DV NTSC Crop to 4x3" so I can apply it again and again without fuss.

Of course, this assumes that when you're shooting you've kept the essential elements within the 4x3 area. If not, you have to go into Final Cut, drag the DVCPRO HD master into a SD 4x3 timeline, adjust the Scale of the clip to crop out the left and right side, and then "Pan and Scan" as needed to preserve the important composition elements.

On a related note, Compressor also does a good job converting 24p DVCPRO HD to 60i DV, though compressor's frame rate conversion is very slow compared to some other solutions, though I simply let it run over night and don't worry about it too much.

[Daniel Kleinfeld]

But wouldn't that then shrink my image down to a lower resolution?

It seems like the trick has something to do with Geometry, but in Compressor 3, I don't see any option for "Crop to 4x3" in the Geometry panel. It seems like the Source Inset (Cropping) fields has the answer, but I can't figure out what I'd need to set them to for a 4:3 ratio. Any suggestions?

Thank you again for your help! I'm thrilled, by the way, by your blog name, and even more thrilled that you have a Les Blank entry on the top----"Chicken Real" is one of my favorite shorts ever.

[Daniel Kleinfeld]

So, I'm continuing to try things, and continuing to be stymied...

My latest thought was to create a custom sequence in Final Cut Pro from which I could export. I tried creating a sequence at NTSC 4:3, with the NTSC Pixel Aspect ratio. And the result is almost right---the sequence comes in, I resize it to 100%, and it's just what I want: Cropped sides, and a 4x3 ratio.

But of course, when exported, it's only 640 x 480 pixels. Now, it seems to me that I ought to be able to get it out at a larger size---exporting a regular 720p file results in an image that's 1280 x 720, so I should be able to get an image that's 960 x 720. But the fact that my movie file, at 100%, fits smoothly (vertically) into a 640 x 480 sequence makes me think... there's something I don't understand.

Is there anyone who could tell me what that is?

[David Tamés]

Yes, going from DVCPRO HD to DV will lower resolution, however, what's the size of the movie they are creating as a Flash video? If it is going to be SD DV resolution or smaller, the technique I describe above will not cause any quality loss.

If you want a high resolution 4:3 master, you can create that using Compressor too, by specifying a non-standard frame size using one of the compressors that do not impose a frame size. DV and DVCPRO HD both work at a specific frame size. You can create an uncompressed (very large) or H.264 compressed movie with non-standard frame size in compressor by creating a custom setting. On the other hand, you've now got on your hands an intermediate file that is quite non-standard.

The way media distribution is going these days, SD video can be 4x3 or 16x9 but HD is always going to be 16x9.

A totally different option is that Flash compressors like Visual Hub and On2 Flix can do the cropping from the DVCPRO HD 16x9 master to create a 4x3 Flash movie (i.e. cropped, not letter-boxed), which is preferable in many respects, as this allows you to start with the highest resolution master, and one that fits a standard.

Does this make sense?

[David Tamés]

Originally Posted by Daniel Kleinfeld

I don't see any option for "Crop to 4x3" in the Geometry panel. It seems like the Source Inset (Cropping) fields has the answer, but I can't figure out what I'd need to set them to for a 4:3 ratio. Any suggestions?.

It's there, I actually walked through the steps in Compressor 3 before writing the post to make sure it was all still the same as in Compressor 2. Click on all the little boxes that are in a line towards the mid-top in the inspector to see all the many options that are available. Set Source Inset to "Crop to: 4:3" and you're there.

Originally Posted by Daniel Kleinfeld

I'm thrilled, by the way, by your blog name, and even more thrilled that you have a Les Blank entry on the top----"Chicken Real" is one of my favorite shorts ever

Thanks. Les Blank is amazing. He was the Filmmaker in Residence at the Woods Hole Film Festival this year so Jon Goldman (a festival board member) and I decided it would be nice to have Les visit Boston while he was in the area, so a group of us organized the event in Boston that I blogged about. I'll reign myself in now, this is getting off topic.