Also as a sidenote: there are some mpeg4 libs out there that compresses files to a fraction of the mpeg2 files. Good for distributing over the net etc. http://www.projectmayo.com/about/index.php http://www.3ivx.com/
Run time: 20:40 34945.avi (38 MB) mpeg4 ! 34945.mpg (365.9 MB) mpeg2 Karl
John.Maloney@disney.com wrote:
Thanks, Nick, this is very helpful.
You're right that stand-alone frames are much easier to edit. In my experiments with Squeak JPEG movies, JPEG movie are generally 1.2 to 3 times larger than the original MPEG movie at similar quality levels. So MPEG is definitely preferable for compactness in final distribution.
But there are many advantages to a format that can be authored and edited in Squeak without the need to buy any additional software. I'm hoping that we can find a way to export a Squeak JPEG movies in a form that can be imported into a high-end video program and turned into a movie in MPEG, Quicktime, or other popular digital video formats for those who desire to publish their movies outside the Squeak community. (I believe that Adobe Premier, for example, can create a movie from a folder full of individual frames, and it would be easy to export all the frames of a JPEG movie.)
-- John
At 7:08 PM +0000 11/28/01, Nick Brown wrote:
On Tue, 27 Nov 2001 18:27:44 -0800, John.Maloney@disney.com wrote:
How widely used is it? Do programs such as Quicktime deal with it?
My aproximate understanding is that it's never used for "end product", as MJPEG files are much larger than their MPEG equivalents. The mid-level video capture hardware (Matrox, etc) seems to like using it
- I think the key point is that its far easier to edit compared to a
file format where you only get a key frame once in a while (ie regular MPEG).
Most of the cheaper tv-card style video grabbers that I've seen don't bother with it, and just go straight to MPEG.
I suppose this boils down to, "Support MJPEG if its nice and easy, but don't bust a gut over it".
HTH, Nick Brown