mpeg streamclip, no image, only sound AVI to MPEG4

Does the video show in MPEGStreamclip when you load it or is it only sound that plays back?

What exactly is the video format? only the sound is specified Pedro.

AVI is a container which can hold a number of different video formats.

MPEG2 conversions require the MPEG2 plugin for Quicktime but they'd normally be .mpg files.

You might want to try adding Perian to your system, might work if it's DivX but may depend on the DivX version (not something I use or obtain).

http://perian.org/

AC

If you want to crop that 4:3 to a 16:9 size losing some image top and bottom then 512x288, is that what you mean?

If you have a 4:3 ratio file of size A x B and want to crop it to 16:9, then it's a fairly simple calculation of:

Movie 4x3 = A x B, crop to 16:9 = A x 9A/16

That may not be what you want.

AC

Multiply the width of your movie by 9/16 to calculate the height.

In your example where the width is 512. Then (512 x 9)/16 = 4608/16 = 288.

Since your original height is 384, then you need to crop 96 pixels or 48 from each of the top and the bottom.

Alley_Cat wrote:
If you have a 4:3 ratio file of size A x B and want to crop it to 16:9, then it's a fairly simple calculation of:

Movie 4x3 = A x B, crop to 16:9 = A x 9A/16

Thought that might confuse using the x ambiguously.

Source 4:3 movie A pixels wide by (x) B pixels high

To crop to 16:9 ratio the width A stays the same but the height B will always be smaller for a 16:9 ratio. B doesn't actually factor in the equation at all, we just know that B will always be bigger than we need!

So the cropped image need to be A pixels wide (unchanged) and 9A/16 pixels high.

Hope that clarifies.

I wouldn't personally bother upscaling that then to 848 x 480 or whatever it was, as you'll only be interpolating the extra pixels - it may be better to let AppleTV scale the smaller resolution image - the encode will be faster and the file size smaller. If in doubt try a short clip with both methods to compare.

AC

I think we can get too hung up on the details - there's not necessarily a perfect answer, but if what you're doing now gives an acceptable result stick with it - I'd only worry if the results were poor.

The black bars top and bottom probably relate to an original 16:9 video converted to be shown 4:3 on a small device with a 4:3 screen - the crop formula should get rid of the black bars most of the time if it's 16:9 in a 4:3 video. Wider videos will still have black bars top and bottom but will look proportional.

I always look for clocks or wheels to try and decide if a video is being played back correctly - if they don't look truly circular as they should then the video is 'squashed' in some direction. Some people don't notice or care which is fine. Basically if it works well for you keep uisng that method.

AC

Pedro you need to crop by 48 top and bottom AND output at 512 x 288.