[FFmpeg-user] FFMPEG producing multiple outputs (one streaming and one snapshot)

[Thomas Chen]

i am trying to capture video from a camera and produce to two outputs
1) streaming (h264)
2) taking periodic snapshot of the image (jpg)

is this possible ?   i read 
https://trac.ffmpeg.org/wiki/Creating%20multiple%20outputs  that
ffmpeg can have multiple outputs but i am not sure how to handle when 
one output is just
snapshot of image (and triggered by an external signal or a periodic 
timer ?)

btw, the camera module i am using can support MPEG (/dev/video0) and 
H264 (/dev/video1),
if i am streaming with H264 (single output), then the MPEG (video0) is 
not operable.

if it is not possible, please advise what other software that can do 
this ? gstreamer ?

thanks