We have discussed already discussed how to install and configure FFMPEG and FFMPEG PHP on CentOS server, while make the configuration getting a error.
This post will help you How to fixed this, 

# cd /usr/local/src
# wget http://downloads.sourceforge.net/faac/faac-1.28.tar.gz
# tar zxvf faac-1.28.tar.gz
# cd /usr/local/src/faac-1.28
# ./configure && make clean && make && make instal

mpeg4ip.h:126: error: new declaration ‘char* strcasestr(const char*, const char*)’
/usr/include/string.h:369: error: ambiguates old declaration ‘const char* strcasestr(const char*, const char*)’
make[3]: *** [3gp.o] Error 1
make[3]: Leaving directory `/usr/local/src/faac-1.28/common/mp4v2'
make[2]: *** [all-recursive] Error 1
make[2]: Leaving directory `/usr/local/src/faac-1.28/common'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/local/src/faac-1.28'
make: *** [all] Error 2

You need to remove the line number 126 in mpeg4ip.h, this file located under common/mp4v2 directory, which means, it does not properly execlude, when it's already included by means of glibc's strcasestr (#define _GNU_SOURCE 1).
# vim common/mp4v2/mpeg4ip.h

#ifdef __cplusplus
extern "C" {
char *strcasestr(const char *haystack, const char *needle);
#ifdef __cplusplus

remove the line or command it "char *strcasestr(const char *haystack, const char *needle);".

Save and quit.

Now, execute the command again.
# ./configure && make clean && make && make install