## Description
There is a segment fault detected by AddressSanitizer

## System info
```
Ubuntu 20.04.2 LTS
clang version 12.0.0-++20210402082642+04ba60cfe598-1~exp1~20210402063359.71
MP4Box - GPAC version 1.1.0-DEV-rev1671-g0cd19f4db-master
```

## Build command
```
./configure --static-mp4box --prefix=`realpath ./install` --enable-sanitizer --cc=clang --cxx=clang++
```

## crash command
MP4Box -sdp -out /dev/null poc_file

## Pocs
[poc.zip](https://github.com/gpac/gpac/files/7950815/poc.zip)

## Crash output
poc_15.mp4
```
AddressSanitizer:DEADLYSIGNAL
=================================================================
==25710==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f05b8d11675 bp 0x7ffe33796cd0 sp 0x7ffe33796488 T0)
==25710==The signal is caused by a READ memory access.
==25710==Hint: address points to the zero page.
    #0 0x7f05b8d11675  (/lib/x86_64-linux-gnu/libc.so.6+0x18b675)
    #1 0x437a4e in fputs (/programs/mp4box/builds/build3/bin/gcc/MP4Box+0x437a4e)
    #2 0x4fe690 in dump_isom_sdp /programs/mp4box/builds/build3/applications/mp4box/filedump.c:1913:3
    #3 0x4e4b46 in mp4boxMain /programs/mp4box/builds/build3/applications/mp4box/main.c:6156:29
    #4 0x7f05b8bad0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #5 0x41ea6d in _start (/programs/mp4box/builds/build3/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libc.so.6+0x18b675) 
==25710==ABORTING
```
There is a segment fault detected by AddressSanitizer
This is a GitHub Issue
repo:gpac
owner:gpac
Title : There is a segment fault detected by AddressSanitizer
Issue date:

--- start body ---
## Description
There is a segment fault detected by AddressSanitizer

## System info
```
Ubuntu 20.04.2 LTS
clang version 12.0.0-++20210402082642+04ba60cfe598-1~exp1~20210402063359.71
MP4Box - GPAC version 1.1.0-DEV-rev1671-g0cd19f4db-master
```

## Build command
```
./configure --static-mp4box --prefix=`realpath ./install` --enable-sanitizer --cc=clang --cxx=clang++
```

## crash command
MP4Box -sdp -out /dev/null poc_file

## Pocs
[poc.zip](https://github.com/gpac/gpac/files/7950815/poc.zip)

## Crash output
poc_15.mp4
```
AddressSanitizer:DEADLYSIGNAL
=================================================================
==25710==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000000 (pc 0x7f05b8d11675 bp 0x7ffe33796cd0 sp 0x7ffe33796488 T0)
==25710==The signal is caused by a READ memory access.
==25710==Hint: address points to the zero page.
    #0 0x7f05b8d11675  (/lib/x86_64-linux-gnu/libc.so.6+0x18b675)
    #1 0x437a4e in fputs (/programs/mp4box/builds/build3/bin/gcc/MP4Box+0x437a4e)
    #2 0x4fe690 in dump_isom_sdp /programs/mp4box/builds/build3/applications/mp4box/filedump.c:1913:3
    #3 0x4e4b46 in mp4boxMain /programs/mp4box/builds/build3/applications/mp4box/main.c:6156:29
    #4 0x7f05b8bad0b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #5 0x41ea6d in _start (/programs/mp4box/builds/build3/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV (/lib/x86_64-linux-gnu/libc.so.6+0x18b675) 
==25710==ABORTING
```
--- end body ---
