Pipe RGB in to ffmpeg?

Hello.  I'm looking for a way to pipe uncompressed RGB image data in to 
ffmpeg.  I apologize for the length of this, I didn't know what all 
information might be helpful so I've included a "brain dump".

Here is a bit of background: in my code I am building video frames, 
720x480x24bit.  I have in mind generating a large number of these, as 
long as a full DVD worth at 30fps, then using ffmpeg (followed by 
dvdauthor) to encode them in to MPEG2 for DVD usage.  Some of my false 
starts:

* Write each frame image as a JPG file.  I can get ffmpeg to accept this 
input, but the quality loss, CPU time to encode each as JPG, and the 
very large number of files, becomes problematic.

* Write each frame image as a PNG file.  Mostly the same problems as above.

* Write them all as frames to an MJPEG AVI file.  Again, ffmpeg is happy 
with this input, and it fixes the many-files problem, but the time to 
compress all those frames and JPG is enormous, and quality loss is still 
there.

* Write them all as frames in a DIB (raw) AVI file.  ffmpeg is happy 
with this also; but as you can imagine the files size is enormous.  
Really, really enormous  :-)

After all that, I figured out that what I need to do is to pipe the 
frames in to ffmpeg as I generate them; thus no disk storage of raw 
video, and no JPG compress/uncompress.  Unfortunately, at this point I 
switch from being able to easily get ffmpeg to do what I want, to an 
unending search for different ffmpeg command lines.  I've read hundreds 
of posts to this list; tried many many commands, and gotten nearly all 
of the same errors that others have reports in other posts  :-)  I am 
using code compiled from CVS sources as of today.

The closest I've found is the yuv4mpegpipe format; I can pipe such a 
file in to ffmpeg and get good results - so I know that piping in 
general works.  Unfortunately the images I am building are in 24-bit (8 
bits of R, G, and B) RGB format, not in YUV.  I can readily write out 
the raw images in DIB/BMP, PPM, or other similar simple format.  But I 
have not been able to find a way to get ffmpeg to accept a series of 
such images piped in on stdin; only to pull each image separate off the 
disk.

Here are some of the command lines I have tried for this; some 
experiments were with PNG files, some JPG, some PPM; none works.  I 
apologize for including mostly the .jpg and .png variations here; I also 
tried many variations with PPM files.


cat ex*.png | ffmpeg -y -f image2pipe -img ppm -i - -target ntsc-dvd dvd.mpg

cat *.ppm | ffmpeg -y -f imagepipe -img ppm -i - -target ntsc-dvd dvd.mpg

cat ex*.png | ffmpeg -y -f image2pipe -vcodec mjpeg -i - -target 
ntsc-dvd dvd.mpg

cat ex*.png | ffmpeg -y -f imagepipe -vcodec mjpeg -i - -target ntsc-dvd 
dvd.mpg


cat *.png | ffmpeg -y -f image2pipe -i pipe:.png -target ntsc-dvd my.mpg

cat *.jpg | ffmpeg -y -f image2pipe -i pipe:.jpg -target ntsc-dvd my.mpg


I would greatly appreciate it if someone who understand these things 
could provide an actual correct command line to do this; or tell me if 
it is not possible, in which case I'll start looking for how to convert 
what I have to yuv2mpeg.

If any of those invocations is already correct, I will be happy to 
follow up with the full and specific ffmpeg output to show the error 
messages, to provide a full example (with a few sample files) etc.

A possible related problem is that in the "Image Formats" section of 
"ffmpeg -formats", I see only this:

Image formats (filename extensions, if any, follow):
DE gif    gif

where I would expect to see other common image formats listed.  This 
makes me wonder if I missed an important option or library when 
compiling.  I saw a few previous posters asking about this with no reply 
though.

--
Kyle Cordes
http://kylecordes.com