Modifying values with in a text string

[cineman]

Hi I’m a novis basic programmer, been programming in basic over the years, but need to do something i have not encountered before, and that is modify the data in a text string by ixerting charators specific places, its containing the path to a file in a subfolder acquired from a filedialog command. The program I’m writing is a GUI for a special application of the popular video editing codec ffmpeg. and in particular the string I want to modify is the data in the subtitle subname$ I'm using Liberty Basic to produce a command line to start ffmpeg and make it do what I want it to do. The liberty basic code i created is this:-

run "ffmpeg -i "+filename$+" -vf subtitles="+subname$+" -f image2 d:\png\%08d.png"

with the paths coming from two filedialog inputs one for the location of the input file in this case called sample.mkv and the subtitle file called sample.srt which produces the following:-

ffmpeg -i D:\dennervision\sample.mkv -vf subtitles=D:\dennervision\sample.srt -f image2 d:\png\%08d.png

If the two files were resident in the ffmpeg folder and this command line is run :-

ffmpeg -i sample.mkv -vf subtitles=sample.srt -f image2 d:\png\%08d.png"

it works just fine but due to a quirk in ffmpeg the portion of the command line relating to the srt file  path causes it to crash and burn. in order for it to work the value in the subname$ needs to be changed from subtitles=D:\dennervision\sample.srt to subtitles='D\:\\dennervision\\sample.srt' complete with inverted commas ' and extra back slashes \ the completed working command line needs to look like this

ffmpeg -i D:\dennervision\sample.mkv -vf subtitles='d\:\\dennervision\\sample.srt' -f image2 d:\png\%08d.png"

But I’m not sure how to go about inserting the extra characters into the text string, ti would need to work with any path regardless of how deep in the file structure the srt file was located so just inserting ' \ at set locations wouldn't work. Can any one tell me how i to go about this please., thanks Mike

[tsh73]

D:\dennervision\sample.srt
D\:\\dennervision\\sample.srt
`D\:\\dennervision\\sample.srt`


' subname$ needs to be changed from
'subtitles=D:\dennervision\sample.srt
'to
'subtitles='D\:\\dennervision\\sample.srt'
'complete with inverted commas and extra back slashe

subname$="D:\dennervision\sample.srt"
print subname$
res$=""
for i = 1 to len(subname$)
   c$=mid$(subname$,i,1)
   select case c$
   case ":"
       res$=res$+"\:"
   case "\"
       res$=res$+"\\"
   case else
       res$=res$+c$
   end select
next

print res$
res$="`"+res$+"`"    'add inverted commas - (`) or (') ??
print res$


[badbug]

Or maybe something like this;


a$ = "subtitles=D:\dennervision\sample.srt"
print a$
a$ = replstr$(a$,"\","\\")
a$ = replstr$(a$,":","\:")
print a$Output:
subtitles=D:\dennervision\sample.srt
subtitles=D\:\\dennervision\\sample.srt

[tenochtitlanuk]

Just as an aside, and possibly a challenge to fellow coders... a nice bit of string manipulation, that LB is very good at.

There is a suggested Rosetta Code task to 'transliterate' some English text to a Greek alphabet version, using the sounds of each Greek letter correctly.However there are a few cases where two letters in English are represented by one in Greek- eg 'theta'. And a special rule for an s at the end of a word taking a different form of 'sigma'.

Unfortunately LB4 does not handle Unicode so can't display the characters- so I use LB to call a web browser and use the html codes like 'α'- alpha.

The target text is
The quick brown fox jumped over the lazy dog.

I was looking at some rhododendrons in my back garden,
dressed in my khaki shorts, when the telephone rang.

As I answered it, I cheerfully glimpsed that the July sun
caused a fragment of black pine wax to ooze on the velvet quilt
laying in my patio.

sphinx of black quartz, judge my vow.
and the output should look like


Will put a page up with my ( messy) solution in a few days. I'm getting time back for some coding after moving house....

[badbug]

Another side on translation.
I'm beginning to see the same pattern here as I did with Run Basic.
So - I gotta go to another language.
Years ago I wrote a conversion from PHP to Run Basic. I think it's still on the Run Basic Forum.
It looks like I have to go back. I'm writing a conversion from Liberty Basic code to PHP.
If anyone is interested I can post the code when finished.

[tsh73]

badbug,
Your code is nice and should work.

But - did you actually tried that
a$ = replstr$(a$,"\","\\")
with LB?

Because for me with LB 4.5.1 it hangs
Just as in this bug report
libertybasiccom.proboards.com/thread/827/replstr-single-quote
first post by bart.

[badbug]

But - did you actually tried that

Yes..It worked.. The output that it shows is actually what I got.

[tsh73]

Probably I'm just not lucky
*killed LB IDE third time*

[xxgeek]

badbugs code doesn't work here either.
same issue as tsh73

tsh73 code works as an example.

So adding code below just before the "run .bla..bla" line should work.



res$=""
for i = 1 to len(subname$)
   c$=mid$(subname$,i,1)
   select case c$
   case ":"
       res$=res$+"\:"
   case "\"
       res$=res$+"\\"
   case else
       res$=res$+c$
   end select
next
res$="`"+res$+"`"    'add inverted commas - (`) or (') ??
subname$ = res$


[cineman]

Hi Tsh73 your code works a treat thank you it just slotted in and worked, just had to rename the srt$ and away it went, brilliant. Thank you. Badbug's code had same problem others seamed to get. It appeared to get into an endless loop forcing me to use task manager to shut it down. I'm still using LB 4.5.1 too. is v5 worth the step? Also, what do people think of the compiler LBB it certainly seems to work most of the time, but it does have some issues relating to strings when i try to compile my GUI on it. some things are broken which run fine on regular LB, haven't bothered to look into the code to see what’s upsetting it. It runs fine on LB so if it ain’t broke don't fix it is my moto, but I’m curious about what it doesn't like none the less. Would be nice to have the GUI as a neat transportable exe.