Question

I am using the following system command to call ffmpeg im my c program:

system("ffmpeg -t 10 -f video4linux2 -s 640x480 -r 30 -i /dev/video0 -f mp4 /home/somepath/webcam.mp4");
system("ffmpeg -i /home/somepath/webcam.mp4 -r 1 -s 640x480 -f image2 foo-%03d.jpeg");

The problem is I need to call the second system only after the first one is completed after 10 seconds. The only way I can think of doing this is using a thread.sleep() and then call it. Is there any other more elegant method of achieving the same?

Answer 1

Quoted from http://www.cplusplus.com/reference/clibrary/cstdlib/system/

int system ( const char * command );

Execute system command

Invokes the command processor to execute a command. Once the command execution has terminated, the processor gives the control back to the program, returning an int value, whose interpretation is system-dependent.

I think system is blocked. So you do not need sleep.