Converting 4:3 avi's to 16:9

[shoosh]

Hi, apologies if this is such a newbie question but I'd be very grateful for some advice. I have a series of documentary avi's in 4:3 ratio which I'd like to convert to 16:9 if possible, without getting that stretched look when the aspect ratio isn't maintained. I've tried ffmpegX but ended up with exactly those results, unfortunately. Is there an easy way to achieve this or am I stuck with the original 4:3 ratio? Thanks a lot for any help.

[manono]

Hi,

I'm not on a Mac, but what you want isn't such a bright idea (in my opinion). There are 2 ways to convert "fullscreen" 4:3, 1.33:1 video to 16:9, 1.78:1 video. One is to crop from the top and bottom, resize, and encode for 16:9. The other is to add black bars to the sides, resize, and encode for 16:9. The former cuts into the actual image, cutting off heads and feet and destroying the director's original framing. The latter loses resolution, although that method is commonly used when both "fullscreen" and "widescreen" material is in the same video. If I were doing it, I'd leave it alone.

On a Windows PC both methods are easily achieved by frameserving into the MPEG-2 encoder using an AviSynth script. Additionally, the first method can also be achieved in a number of ways, including a special setting for just this in DVD-Rebuilder. The Mac people here can tell you if either method is possible on a Mac, and how it's done.

[rumplestiltskin]

MPEG Streamclip. Use the "crop" option and cut off as much of the top and bottom as you wish. Of course, you're losing part of the picture but that's what you get when you go down this road.

[guns1inger]

For NTSC, crop off 60 lines form the top, 60 from the bottom, then resize up to 480 lines and re-encode.

Personally, on the few occasions I have had to do this type of thing, I have always done it with my NLE so that I can dynamically reframe the image within the new aspect ratio to reduce the damage done. It can be a time consuming process to make it look reasonable, and not something that can be automated. You are effectively doing a vertical Pan and Scan process.

[shoosh]

Okay, thanks for the advice. I'll chalk this one up to experience and file it away in my 'not-so-great ideas folder', which is stuffed full as it is. 8) Live and learn.

[guns1inger]

There are valid times to do this, so it is worth understanding how to do it, and the pitfalls to avoid or minimise. If you have to mix 4:3 and 16:9 material, then pillarboxing is a valid approach. If you you have a camera that does non-anamorphic 16:9 (essentially letterboxing) then you might also choose to do this, simply for convenience on 16:9 playback equipment. It is when you try to crop 4:3 full frame material that was not shot with cropping in mind that you run into problems.