PHP exec calls FFmpeg automatic transcoding video does not execute, how to handle

PHP exec calls FFmpeg automatic transcoding video does not execute
To a customer to do phpcms field development, in fact, the transfer of video transcoding function, the local test passed, UAT environment also passed. After the customer uploads to the production environment, Transcoding does not execute, UAT environment and production environment, are WIN2003+IIS6.

Cmd. EXE and Ffmpeg.exe permissions are given, everyone,iis,guest and so on, all are fully control, run exec (' ipconfig '), can output the user IP information correctly, prove CMD.EXE permissions yes, but run exec (' Ffmpeg.exe-i test.wmv test.mp4 ') Such commands always fail to execute. The path problem of Ffmpeg.exe and video files can be excluded, and both relative and absolute paths have been tested.

GOOGLE, Baidu found a bunch of information, or no solution, there is no big God help analysis under what might be the reason?
------Solution--------------------
This kind of thing is really difficult to say where the problem is, basically to eliminate the wrong problem you have been ruled out, in a separate implementation of the transcoding command function is normal? Or take your part of this feature to another win2003 system and test it out.
------Solution--------------------
Ffmpeg.exe need to have anonymous user execution rights

Absolute paths are required for both Ffmpeg.exe and video files
You can verify this by using the cmd file in the same directory as the PHP file.

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