Converting MKV for use in non-linear editor; also changing aspect ratio

[noctrine]

Hello all,

First off, let me say how much I love this site. The tutorials and FAQs have gotten me much closer to my goal. I still have a few questions and I'm hoping you all can help. I'm assuming the system specs I entered will be in my sig or something, but I'm primarily using a MacBook Pro with Lion and iMovie '11. I have access to a Win7 machine. Both are fast and ~1 year old.

I have an MKV from a Blu ray that I want to use for a mashup (string together movie excerpts for hilarity). Here are the gory details on the codecs http://pastebin.com/S9xTpeYJ

Problem number 1: the aspect ratio is about 2.4:1. My iMovie project will be 16x9. How can I pad it with the horizontal black bars so iMovie won't scrunch it when editing?
Problem number 2: what is the preferred workflow for converting to some format that is ideal for editing? I have tried a couple different outputs from MPEG Streamclip, and I can get those outputs into iMovie, but I am still fighting the aspect ratio issue. If I export to a .mov using h264 it looks great, but stays 2.4:1 and iMovie cheerfully chops off the sides. It increases the file size 6-fold but I understand that's expected and necessary for NLE. I want to rest assured that the hours I put in chopping up this movie will be using the best quality source and that I'm not making any up front mistakes that will bite me later.

Other questions:
-My final iMovie project will be 720p. At what point will I be downscaling the 1080p MKV to 720?
-The MKV is 6 channel DTS. The final iMovie project will be humble stereo. Do I need to do anything here?
-I tried messing around with ffmpegX but I get the following error when trying to convert this MKV to a DV file http://pastebin.com/hwEXExny Google wasn't much help here.
-The MKV is 24 FPS. I think the iMovie project will be 30 FPS. iMovie asks if I want to change the project to 24 when I import a sample clip, but if I say no it still seems to work. Is this ok or is it doing something weird?

THANK YOU all very much in advance.

[Baldrick]

Try resize the video to 1280x720 in mpeg streamclip and you should get black borders (see http://www.foolishpassion.org/vidding-tips/fixing-squished.html for some tips).

Convert the dts to wav with some tool...maybe eac3to.

Can't you make a 24fps project in imovie? It's best to avoid frame rate conversion because of jumpy playback and audio sync issues.

[noctrine]

I used MPEG Streamclip to export to 1280x720 (I had read that foolishpassion.org page) but it just narrows the video causing everyone to look skinny. I've tried exporting to DV and MOV with Apple Intermediate and DV codecs. I don't see any option to "pad." There are scaling and cropping options but that's not what I want to do.

Also, I linked to the error in my original post, but I can't figure out why ffmpegX won't process the input file.

Thanks again!

[Baldrick]

Try change the X/Y: to 1.333 in mpeg streamclip. Hit Preview and see how it looks like.

edit: I just tried mpegstreamclip with a 1024x428pixels(2.40:1) source resized to 1280x720p with the X/Y: 1.33 and it looks fine with black borders.

[noctrine]

Thank you, I'll check it out.

However, for the current clip, it turns out iMovie '11 *can* do the padding. The default setting when you add a video to a project that doesn't conform to the aspect ratio is "crop." But if you click on the little blue gear and select "cropping and rotation" and change "crop" to "fit" it'll do just that; add the necessary padding so it fits to the new aspect ratio without distortion or loss of pixels.

In terms of my other issues:
-the whole project will be 24fps to avoid conversion issues
-using MPEG Streamclip, I can output to .mov using H.264 which iMovie '11 seems to tolerate. The gamma is still off but you can darken it back to normal in iMovie. This step also changes the 5.1 DTS to stereo PCM.
-ffmpegX was failing because it doesn't support the DTS audio codec. But it's a non issue for me because MPEG Streamclip can do everything I need (it seems).

Thanks again!

[edDV]

iMovie doesn't support 24p. It wants to see telecined 1080i or 480i.

Interlace isn't supported for 1280x720, instead frame repeats to 59.94p would be supported. Any conversion of film source to 1280x720p/30 or 960x540p/30 will be jittery.

Best compromise for iMovie is to edit telecined 1440x1080i.