php exec（）适用于某些调用，不适用于其他相似的调用

Question

I have a php script that cuts up video. Here are three exec() commands - two execute properly while one does not:

Works:

sudo ffmpeg -i /home/vidserver/videos/$filename.mp4 -ss $ctime -t 00:00:06 -acodec copy -vcodec copy -y /var/vidcache/test$x.mp4

Works:

sudo ffmpeg -i /var/vidcache/test$x.mp4 -qscale:v 1 /var/vidcache/i$x.mpg

Does not work:

sudo ffmpeg -i concat:"i0.mpg|i1.mpg" -qscale:v 1 /var/vidcache/output.mpg

/var/vidcache has 777 privs and www-data is in the sudoers file with NOPASSWD (yes, I know - this is just for debug purposes before I lock down security).

When I run the last command from a php script from the command line by itself, it DOES work. (Running as www-data or root.) But when I try to put it in a function called from a web page, it does NOT work.

Any ideas?

Answer 1

This should fix the third exec:

sudo ffmpeg -i "concat:i0.mpg|i1.mpg" -qscale:v 1 /var/vidcache/output.mpg

Here is a good wiki page on how to concat media files in ffmpeg .

Answer 2

Actually, the answer was as stupid as "where does www-data know where to look for files?"

I was assuming a lot with the i0.mpg. It needs a fully qualified directory, obviously.

Anyway, changing the code to look like this worked:

sudo ffmpeg -i concat:"/var/vidcache/i0.mpg|/var/vidcache/i1.mpg" -qscale:v 1 /var/vidcache/output.mpg