[WINDOWS] problems with variables when launching from mpv

[masterofobzene]

I use input.conf to launch certain cmd batch files to do stuff with files being played in mpv.

for example I use a 4 letter trigger to launch a script:
T-E-S-T run "E:\\Perfil\\Desktop\\0005.TEST.c.ms.CMD" "${path}"; show-text "TEST"

The script uses "%1" variable to deal with the file currently playing. It seems that mpv doesn't like "%1" and just says nothing is there ONLY IF I PLAY A WHOLE FOLDER (it's contents). The variable WORKS (and the whole script too) if I only play ONE file (a single video).

To be clear; files are always played by mpv, what fails is my manually launched CMD that moves the files currently being played.

TLDR: seems like mpv is not passing variables correctly to my batch file, in this case "%1" variable.

[masterofobzene]

I think this question will be a long trip to "we need all info" and/or "I don't understand" kind of replies so I'm going to keep posting my findings alone and if somebody knows whats going on, please reply.

Now, to focus on this:

The batch is acting weird. The file below IS NOT in the folder that it checks, but it still returns "true" as if the file was there:

C:\Users\PC>if exist "E:\Perfil\Desktop\[TEST_2]\2020-09-27_09-02-16_178~1__-seg37.mkv" GOTO RENAMEVID else GOTO MOVEFILEVID

C:\Users\PC>ren E:\Perfil\Desktop\TEST_1/2020-09-27_09-02-16_178~1__-seg37.mkv "2020-09-27_09-02-16_178~1__-seg37_31251.mkv"
The syntax of the command is incorrect.

C:\Users\PC>MOVE "E:\Perfil\Desktop\TEST_1\2020-09-27_09-02-16_178~1__-seg37_31251.mkv" "E:\Perfil\Desktop\[TEST_2]"
The system cannot find the file specified.

To dissect this:
if exist "E:\Perfil\Desktop\[TEST_2]\2020-09-27_09-02-16_178~1__-seg37.mkv" GOTO RENAMEVID else GOTO MOVEFILEVID

The batch is erratically thinking the file "2020-09-27_09-02-16_178~1__-seg37.mkv" is inside "E:\Perfil\Desktop[TEST_2]" which is not true. The batch evaluates if the file is already in the destination folder and if its true, it renames it then moves it; if it's not true it just moves it. In this case, the batch is wrongly evaluating that the file IS in the destination. WEIRD. At this point I want to say that this batch job works in windows directly; it only fails when launched from mpv.

The script decides that the file must be renamed cause it "thinks" that a file with the same name is already in the destination, but pay close attention to what happened:

C:\Users\PC>ren E:\Perfil\Desktop\TEST_1/2020-09-27_09-02-16_178~1__-seg37.mkv "2020-09-27_09-02-16_178~1__-seg37_31251.mkv"
The syntax of the command is incorrect.

I will highlight it for you:
ren E:\Perfil\Desktop\TEST_1/2020-09-27_09-02-16_178~1__-seg37.mkv
Look for the separator here ↑

mpv for some reason is changing "%1" (in this case %1 = E:\Perfil\Desktop\TEST_1\2020-09-27_09-02-16_178~1__-seg37.mkv) and it's adding / instead of \ that is the windows separator.

The 3rd command obviously fails since the "renamed file" was never renamed:

C:\Users\PC>MOVE "E:\Perfil\Desktop\TEST_1\2020-09-27_09-02-16_178~1__-seg37_31251.mkv" "E:\Perfil\Desktop\[TEST_2]"
The system cannot find the file specified.

So up until here, I see many strange things:
1- I don't know why is my batch file evaluating a wrong "if exist"
2- I don't know why MPV is adding/changing that separator to a linux one.
3- I don't know why if loading a single video into mpv, everything works.
4- I don't know why if loading many videos or a folder into mpv, the problems arise.

[masterofobzene]

It seems that when ren E:\Perfil\Desktop\TEST_1/2020-09-27_09-02-16_178~1__-seg37.mkv (bad separator added) it was due to a bad code in my batch: I had "%DESTVID%%~nx1" instead of "%DESTVID%\%~nx1"
So I added the missing "\" and the "weird linux separator" was gone.

One less to troubleshoot.

Sadly, the script is still evaluating wrong and insists on renaming the file:

if exist "E:\Perfil\Desktop\[TEST_2]\2020-09-27_09-02-16_178~1__-seg37.mkv" GOTO RENAMEVID else GOTO MOVEFILEVID

:RENAMEVID 
ren E:\Perfil\Desktop\TEST_1\2020-09-27_09-02-16_178~1__-seg37.mkv "2020-09-27_09-02-16_178~1__-seg37_9276.mkv"

[masterofobzene]

Well, just discovered something:

For some magical reason that I do not comprehend because my limited knowledge, "if exist" is being evaluated wrongly when launching the batch file from mpv. I assure you that this script worked without changes if used inside windows directly. So I will answer my own questions for people that end up here:

1- I don't know why is my batch file evaluating a wrong "if exist"

Black magic. Mpv does something when executing batch files that changes the native behaviour. The fix: using "if not exist" and flipping around the actions after it.

2- I don't know why MPV is adding/changing that separator to a linux one.

Auto-answered above, It was my fault in my script. Mpv was trying to "fix" my typo with "it's own separator". This is specified somewhere in the manual, but was a little vague and ambiguous. Still, it was a "typo" because I forgot to add a separator there.

3- I don't know why if loading a single video into mpv, everything works.

No freaking idea. Still a mistery but I suppose it has something to do with for example "%1" not working properly and having to declare it into a new variable. This is important "%1" argument variables (something like "current selected file") is not playing nice with mpv and needs to be re-declared into another "formal" variable e.x. SET "SOMENAME=%1". %1 is a null variable when launching batch files from mpv. All this happens when loading multiple files, folders or playlists; it works when launching individual files.

I will close this because I think I solved my issue, feel free to see if this can be fixed in the future or at least answered to me here if I'm missing something.

[avih]

Normally windows applications don't have an issue with path separator being \ or /, because the windows API handles them effectvely identically, and both are valid and mean the same thing.

However, one big exception is cmd.exe (which also interprets batch files), which doesn't use the normal windows API, and instead has its own interpreter and very weird rules (really, if you want to do yourself a favour, get away from batch files).

3- I don't know why if loading a single video into mpv, everything works.

Because mpv doesn't modify ${path} if it's a direct argument to mpv, so if it was invoked with only \ separators then the batch file will work.because ${path} has only \ separators.

But if the argument is a directory, then mpv generates ${path} by concatenating the dir name and the file name - you guessed it - using / separator.

It does that because it's simpler code, and normally windows applications have zero issues with that, except, like you just found out, in batch files.

This was discussed quite a few times in the past, with several suggested solutions (you'll have to search the issues), some of them involve changing mpv code itself, and others using a small script which can fix it if needed.

So far the mpv developers stick to keeping it only / when a path is generated from components, because it is simpler code.