GUI for ffmpeg and mrlib/terminal

[James]

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. MrLib/terminal seems like just the thing except there are various ways that it isn't as good as it could be for this kind of project. It's mostly small things, for example, the cancel button is labeled "Abort Instillation" by default. The one thing which is not so simple is that it looks like it is intended to just run one command and not create an interactive environment. I was expecting to be able to send commands to the terminal% object in order to run things one after another. Instead, you pass a function as a parameter when you create the terminal% object and it just runs that function. So, either I have to close the terminal and open a new one each time I run a command or I suppose that I could have the function work with a thread mailbox or channels so that I could keep using it. My question is whether MrLib Terminal the best option for this kind of work or is there a better bet?

https://docs.racket-lang.org/mrlib/Terminal_Window.html

James

[Leif Andersen]

Well James, you're in luck.

The short answer is, yes, yes you can. You should check out video at
http://lang.video (you can follow the progress either on the blog, the
twitter feed http://twitter.com/videolang , or on github itself:
https://github.com/videolang/video . Alternatively, you are welcome to
arrange a call with me some time so we can coordinate our efforts.


The (slightly) longer answer is: you can find the (private and thus
unstable) bindings here:
https://github.com/videolang/video/tree/master/video/private/ffmpeg;
and my (very early) prototype NLVE widgets here:
https://github.com/videolang/video/blob/master/video/private/editor.rkt.
In either case, contributions are absolutely welcome. Bug reports are
also welcome and very helpful.

I hope that helps, and feel free to ask any questions. If you are
interested in creating GUIs for Video editing we should also sit down
for a chat some time. (Either in person or via teleconference.)

Anyway, I hope you have a lovely day.

~Leif Andersen

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[David Storrs]

That is very cool, Leif.

Still, I'm also interested in the original question:  if I wanted an interactive GUI terminal in Racket, what's the best way to do it?

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[Neil Van Dyke]

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.

[William G Hatch]

On Wed, Aug 30, 2017 at 09:57:01AM -0400, David Storrs wrote:
>Still, I'm also interested in the original question: if I wanted an
>interactive GUI terminal in Racket, what's the best way to do it?

Another thing you can look at is my Rackterm package[1]. It is currently an undocumented mess (and the first Racket project I made over a couple hundred lines), but it is also a reasonably compliant xterm that handles colors/styles, curses applications (eg. emacs and vim work fine in it), etc. I've always intended to clean up the parser and make it available as a library for applications that want to parse and use input with ANSI control characters in it, make the various pieces available as stable interfaces for embedding terminals into applications, etc. I haven't gotten around to doing that, but there is an unstable terminal-canvas.rkt that provides the terminal gui widget.

[1] https://github.com/willghatch/rackterm

[Leif Andersen]

> Another thing you can look at is my Rackterm package[1].

Wow, that's nifty. :)

> Still, I'm also interested in the original question: if I wanted an interactive GUI terminal in Racket, what's the best way to do it?

Fair. Will's RacketTerm project looks like a good resource. Another
resource I think is very helpful is Matthew's `slideshow/repl`
package: https://github.com/mflatt/slideshow-repl

Specifically, it shows you how you can make a repl text in an editor%
in a frame%. Specifically, I would recommend checking out:

`slideshow/private/editor.rkt` in that repo. The two classes
slide:text% and repl-text% (lines 58-368) should show you how to get
started.

The mrlib/terminal library is cool, but it hasn't been touched for 5
or so years.

~Leif Andersen

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[Leif Andersen]

(Although to be clear, slideshow-repl will show you how you can set up
a repl rather than a terminal. But I suspect they will be similar in
the gui-building respect.)

~Leif Andersen

[James]

On Aug 30, 2017, at 10:23 AM, Neil Van Dyke wrote:

> 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.

Right. It would be good to handle error messages but there are also warnings and prompts. For example, if the output file already exists, it asks whether you want to overwrite. Warnings should be shown prominently but not reacted to.

Currently, I am using the cleanup-thunk from MrLib Terminal to notify the user when the process is done but a progress bar would be much nicer. Ffmpeg has a --progress parameter which sends progress information to a url. That may be useful.

James

[James]

This too. I meant this to go to the list.

Begin forwarded message:

> From: James <jbiom...@gmail.com>
> Date: August 30, 2017 4:29:39 PM EDT
> To: William G Hatch <wil...@hatch.uno>
> Subject: Re: [racket-users] GUI for ffmpeg and mrlib/terminal

>
>
> On Aug 30, 2017, at 12:24 PM, William G Hatch wrote:
>
>> On Wed, Aug 30, 2017 at 09:57:01AM -0400, David Storrs wrote:
>>> Still, I'm also interested in the original question: if I wanted an
>>> interactive GUI terminal in Racket, what's the best way to do it?
>>
>> Another thing you can look at is my Rackterm package[1]. It is currently an undocumented mess (and the first Racket project I made over a couple hundred lines), but it is also a reasonably compliant xterm that handles colors/styles, curses applications (eg. emacs and vim work fine in it), etc. I've always intended to clean up the parser and make it available as a library for applications that want to parse and use input with ANSI control characters in it, make the various pieces available as stable interfaces for embedding terminals into applications, etc. I haven't gotten around to doing that, but there is an unstable terminal-canvas.rkt that provides the terminal gui widget.
>>
>> [1] https://github.com/willghatch/rackterm
>

> This sounds good. Besides ffmpeg, there are many other situations where it would be good to have a combination of a GUI and interactive terminal. In the past, I have created quite a few AppleScript droplets which you drag files onto and it loops through them, running a command on each one in a Terminal window. Sometimes, it's useful to hit the up arrow in Terminal after a command is done, edit and rerun it, as a one-off thing, rather than having to edit the AppleScript.
>
> Ffmpeg gives both warnings and error messages. MrLib Terminal just displays all text in red. In the macOS Terminal, ffmpeg highlights different warnings and errors in different colors. One error that I am running into, since I am testing repeatedly, is "Output file already exists. Overwrite? y/N." At that point, there is no way to respond and i just have to cancel and try again. I suppose that I can catch that specific situation in my Racket code and handle it but it would still be nice to be able to respond to other unanticipated prompts.
>
> James

[James]

I had meant to send this to the list also.

Begin forwarded message:

> From: James <jpl...@biomantica.com>
> Date: August 31, 2017 10:48:29 AM EDT
> To: Racket Users <racket...@googlegroups.com>
> Subject: Fwd: [racket-users] GUI for ffmpeg and mrlib/terminal
>
> I had meant to send this to the list as well...

>
> Begin forwarded message:
>
>> From: James <jbiom...@gmail.com>
>> Date: August 30, 2017 4:26:24 PM EDT
>> To: Leif Andersen <le...@leifandersen.net>
>> Subject: Re: [racket-users] GUI for ffmpeg and mrlib/terminal
>>

>> As mentioned earlier, my primary goal right now is to learn GUI programming but I do have a side interest in video editing. I can't spend a lot of time on it but I definitely can at lest do some testing and bug reports. One thing on my agenda is to eventually find a replacement for QuickTime 7 Pro. This is the simplest and easiest editor, by far, for the most common, basic things I want to do. Those of us who paid Apple $30 for the Pro version, eight years or so ago, are still able to run QuickTime 7, alongside 10, in order to have the better editing capability of the old version. I still use it but I'm sure it's days are numbered. In fact, one of the more common things I do with ffmpeg is convert video from newer formats to something that QuickTime 7 can open and edit. I have been intermittently trying out potential substitutes but, so far, none of them have been much good in my opinion.
>>
>> James

>>
>>
>> On Aug 29, 2017, at 7:40 PM, Leif Andersen wrote:
>>
>>> Well James, you're in luck.
>>>
>>> The short answer is, yes, yes you can. You should check out video at
>>> http://lang.video (you can follow the progress either on the blog, the
>>> twitter feed http://twitter.com/videolang , or on github itself:
>>> https://github.com/videolang/video . Alternatively, you are welcome to
>>> arrange a call with me some time so we can coordinate our efforts.
>>>
>>>
>>> The (slightly) longer answer is: you can find the (private and thus
>>> unstable) bindings here:
>>> https://github.com/videolang/video/tree/master/video/private/ffmpeg;
>>> and my (very early) prototype NLVE widgets here:
>>> https://github.com/videolang/video/blob/master/video/private/editor.rkt.
>>> In either case, contributions are absolutely welcome. Bug reports are
>>> also welcome and very helpful.
>>>
>>> I hope that helps, and feel free to ask any questions. If you are
>>> interested in creating GUIs for Video editing we should also sit down
>>> for a chat some time. (Either in person or via teleconference.)
>>>
>>> Anyway, I hope you have a lovely day.
>>>
>>> ~Leif Andersen
>>>
>>>
>>> On Tue, Aug 29, 2017 at 3:57 PM, James <jbiom...@gmail.com> wrote:

>>>> 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. MrLib/terminal seems like just the thing except there are various ways that it isn't as good as it could be for this kind of project. It's mostly small things, for example, the cancel button is labeled "Abort Instillation" by default. The one thing which is not so simple is that it looks like it is intended to just run one command and not create an interactive environment. I was expecting to be able to send commands to the terminal% object in order to run things one after another. Instead, you pass a function as a parameter when you create the terminal% object and it just runs that function. So, either I have to close the terminal and open a new one each time I run a command or I suppose that I could have the function work with a thread mailbox or channels so that I could keep using it. My question is whether MrLib Terminal the best option for this kind of work or is there a better bet?
>>>>
>>>> https://docs.racket-lang.org/mrlib/Terminal_Window.html
>>>>
>>>> James
>>>>