命令通过终端正常工作，但不能通过shell_exec php运行

Question

Got a weird issue i have installed wav2png on my mac osx with lion now and works fine when using terminal no problem but when i try to run it using shell_exec with php like below

$wav2png = shell_exec("cd {$targetDir} && /usr/bin/wav2png --foreground-color=000000ff --background-color=00000000 -o example2.png f86150f88d.wav 2>&1");
echo "<pre>" . $wav2png . "</pre>";

I get the output

dyld: Library not loaded: /opt/local/lib/libpng15.15.dylib
  Referenced from: /usr/bin/wav2png
  Reason: Incompatible library version: wav2png requires version 28.0.0 or later, but libpng15.15.dylib provides version 23.0.0

Cant find a way to update libpng???

Any suggestions why it will work fine through terminal but not shell_exec php?

Answer 1

I think problem is in LD_LIBRARY_PATH and/or with library paths in general.

Go to shell and type

echo $LD_LIBRARY_PATH

and

ldd /usr/bin/wav2png

Do exact same from php script (be sure to grab output from these commands) and compare, I'm pretty sure you find the answer.