James wrote on 08/29/2017 03:57 PM:
I have been working through The Racket Graphical Interface Toolkit 
documentation to learn GUI programming and I thought I would do a small but 
useful project.  The idea is to make a simple GUI front end which will 
formulate commands for ffmpeg to do various video and audio conversions on 
selected files and then run those commands.

James, this is a great idea GUI learning exercise (and coincidentally I did a very similar thing for one of my first GUI programs, for a different technical command line program with lots of complicated options). I think you should do this.

Considering that "ffmpeg" is normally non-interactive, you don't necessarily need full terminal functionality. You just need something like Racket `subprocess` or `process*/ports`, and to write I/O-ish code to monitor the stdout and stderr output, and do appropriate GUI things.

Specifically, you might want to do a few things with the stdout/stderr output: * Store some raw form of it (space-limited, like ring buffer), in case user selects to show this in a GUI text viewer, or display it as ffmpeg runs. * Monitor it for error messages (you can use regexps), and present them in a GUI-friendly way. * Monitor it for progress information, and turn that into a GUI progress bar or similar, since ffmpeg can take minutes or hours to run.

There's also some UI design challenges here. At first, you might want to translate a bunch of command line arguments into GUI elements. After doing some of it manually, you might also look at making it data-driven (e.g., you come up with a minilanguage representing pertinent semantics of the ffmpeg command line options, and then write code that translates that to appropriate GUI elements. Before/after that you might want to look at things like saving configurations (minilanguage helps here), and providing higher-level "task" interfaces. (Say, a task is to convert various video file formats to 1080/60p in a particular container and codec profile, preserving aspect ratio. And maybe you can figure out how to remove letterboxing black bars automatically from the original videos.)

I threw out a few ideas for where you might take this, for later reference, but the thing to do is to just sit down in front of a DrRacket, and start building up code to handle the process and/or create the GUI elements. At some point, you can come back to people's comments and decide where you want to go next.

--
You received this message because you are subscribed to the Google Groups "Racket 
Users" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to racket-users+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.

Reply via email to