ffmpeg single quote in drawtext

Question

I haven't been able to get ffmpeg's drawtext video filter to draw apostrophes/single quotes when they are in drawtext's "text=" parameter, even when I escape them. Double quotes work fine, and apostrophes in text loaded from a file (e.g. textfile="example.txt") work fine. Is this a bug?

e.g.

ffmpeg -i test.mpg -vf drawtext="apostrophes don't print" ...
ffmpeg -i test.mpg -vf drawtext="even when they\'re escaped" ...

Answer 1

Special character escapes are like violence: if they're not solving your problem, you're not using enough.

ffmpeg -i test.mpg -vf drawtext=text="It\\\\\'s so easy"

Produces a textual overlay that includes an apostrophe. The text is being parsed a couple times, so you not only have to escape the quote, you also have to escape the slash escaping the quote. Twice.

Your alternative of using a textfile might be a better method in this situation.

Answer 2

I was able to insert Unicode \u2019 into argument string and it worked for single right quote.

Answer 3

In case someone needs this for python, this escape function is working for me (based on https://ffmpeg.org/ffmpeg-utils.html#Quoting-and-escaping + multi-escaping advice above):

return "'" + text.replace(":", "\\:").replace("'", "'\\\\\\''") + "'"

Answer 4

// This works for me

public function replaceSpecialFfmpegChars($text)
    {
        return str_replace(
            ":",
            "\\\\\\\\\\\:",
            str_replace(
                "%",
                "\\\\\\\\\\\%",
                str_replace(
                    "'",
                    "'\\\\\\\\\\\\''",
                    str_replace(
                        "\"",
                        "\\\\\\\\\\\"",
                        str_replace(
                            "\\",
                            "\\\\\\\\\\\\\\\\",
                            $text
                        )
                    )
                )
            )
        );
    }

Answer 5

This is probably something to do with magic quotes. Through a bunch of testing I just did using Windows Command Line and MinGW on Windows, I ran into the same problem every time. Since ffmpeg drawtext uses Freetype (I would guess this is where magic quotes are enabled) I doubt there's much to be done to disable magic quotes. I'm not sure there's a way to remove the added slashes in the command line either, as everything I've seen involves PHP scripts. I could be wrong, since I'm no PHP guru, but I'm not aware of how to integrate them into an ffmpeg command.

Answer 6

Just put your text into a file e.g. myText.txt and use textfile option:

->myText.txt This is my text with special characters :,(,),'

Then instead of using :

ffmpeg -i test.mpg -vf drawtext="This is my text with special characters :,(,),'"

use the following command:

ffmpeg -i test.mpg -vf textfile=textFile.txt

Answer 7

If you're passing the string via Python, the following works for me:

txt = 'it\'s good!'
txt = txt.replace('\'', '\'\\\\\\\\\\\'\'')