ala888 Posted July 13, 2014 Share Posted July 13, 2014 oftentimes, php users will execute ffmpeg in shell alongside a series of variables to designate a specific action that the individual wants to perform. However, I am not quite able to grasp the idea of how ffmpeg grabs the variables passed to it from shell? Is it because it contains inset capability of this? if so, could someone point me to what this type of C++/C programming feature is? Or rather, if its a capability of shell, could someone explain that to me? ffmpeg -i in.avi -codec:v libvpx -quality good -cpu-used 0 -b:v 500k -qmin 10 -qmax 42 -maxrate 500k -bufsize 1000k -threads 4 -vf scale=-1:480 -an out.webm like how does ffmpeg grab all these variables from shell? Link to comment Share on other sites More sharing options...
Hadien Posted July 13, 2014 Share Posted July 13, 2014 It's merely another language. this is command line code, cprompt, DOS. you could open up your command prompt in Windows start menu, set the current directory (the "CD" command) to where ffmpeg is and use the code you just posted. The prompt will know that you are sending a command to the file "ffmpeg" and the flags (delimited via the "-" symbol) will parse out all the variables included. Link to comment Share on other sites More sharing options...
ala888 Posted July 13, 2014 Author Share Posted July 13, 2014 can the same flags be used for other programs then? Link to comment Share on other sites More sharing options...
Hadien Posted July 14, 2014 Share Posted July 14, 2014 each program has their own flags, you can run [program's name] /? or [program's name] /help in cprompt and it will list out all the flags the program can respond to. if you also include the flag then dos should print out some useful description about the flag Link to comment Share on other sites More sharing options...
ala888 Posted July 14, 2014 Author Share Posted July 14, 2014 Is it possible to add additional flags to existing programs? say to bypass the GUI for automation purposes? Or is this pointless if I dont have access to the source code and there is no inbuilt support for flags Link to comment Share on other sites More sharing options...
justsomeguy Posted July 21, 2014 Share Posted July 21, 2014 Linux shells have several options of their own, for example you can pipe output to a file or somewhere else other than the console, or you can use a file as input for when the program expects input. As far as a writing your own program that checks for command line arguments, in C the number of arguments and the values are passed to the main loop. They are commonly referred to as argc and argv. Link to comment Share on other sites More sharing options...
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