[FFmpeg-user] writing output via image2 to stdout

[ffmpeg at afkbio.de]

I am using ffmpeg to exctract single images from a video, at the rate of one image per second.
Per default I have to specify an output format like img-%03d.jpeg and the images will get written to disk one by one.

I am calling ffmpeg from within another program, so ffmpeg writes the images to disk and my application reads them afterwards.
However I'd love to be able to grab the results directly from stdout to process them further but FFMPEG won't let me do this:

The first image is returned via stdout and when it comes to processing the second one it errors out with 
>[image2 @ 00000000043100A0] Could not get frame filename number 2 from pattern 'pipe:'

Is there any workaround for this (if yes, how would I know where to split the datastream in separate imaghes?) Is there any other possibility how I can transfer the ffmpeg output directly to my application without having to write on disk?

Thanks!