Question

I try and try again with Regex, I just don’t get it. I’m trying to traverse a log file for FFMPEG and get the FPS.

Basically, on a variable line (seems to be around 16/17) of the log file this line appears:-

Stream #0.1[0x1e0]: Video: mpeg1video, yuv420p, 640x480 [PAR 1:1 DAR 4:3], 104857 kb/s, 25 fps, 25 tbr, 90k tbn, 25 tbc

I’d like to traverse line by line, which I think I can do exploding by /n and then for loop through, but I’d prefer to just get the line that line, and then get the FPS value.

Any pointers gratefully received.

Answer 1

You could try this:

if (preg_match('/^Stream #0.*?(\b\d+(?:\.\d+)?\s*fps\b).*/m', $subject, $regs)) {
    $full_line = $regs[0];
    $result = $regs[1];
} else {
    // no match...
}

Explanation:

^     # start of line (/m modifier makes sure that this works)
Stream #0  # match Stream #0 literally
.*?   # match any number of characters, as few as possible
(     # then capture the following
 \b   # starting at a "word" boundary
 \d+  # one or more digits
 (?:  # try to match the following:
  \.  # a dot
  \d+ # followed by one or more digits
 )?   # but make that optional
 \s*  # optional whitespace
 fps  # literal fps
 \b   # end at a word boundary
)     # end of capturing group
.*    # match the rest of the line