## 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-rev1727-g8be34973d-master
```

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

## crash command
```
MP4Box -isma -out /dev/null poc_file
```

## Pocs

[poc.zip](https://github.com/gpac/gpac/files/8020744/poc.zip)


## Crash output
```
==7355==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000004 (pc 0x0000008f9bfe bp 0x7ffea000f9f0 sp 0x7ffea000f600 T0)
==7355==The signal is caused by a READ memory access.
==7355==Hint: address points to the zero page.
    #0 0x8f9bfe in gf_media_make_isma/programs/mp4box/builds/build10/src/media_tools/isom_tools.c:445:37
    #1 0x4e4934 in mp4boxMain/programs/mp4box/builds/build10/applications/mp4box/main.c:6332:8
    #2 0x7f224ff820b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x41ea6d in _start (/zhengjie/cmdline-fuzz/programs/mp4box/builds/build10/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV/programs/mp4box/builds/build10/src/media_tools/isom_tools.c:445:37 in gf_media_make_isma
==7355==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-rev1727-g8be34973d-master
```

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

## crash command
```
MP4Box -isma -out /dev/null poc_file
```

## Pocs

[poc.zip](https://github.com/gpac/gpac/files/8020744/poc.zip)


## Crash output
```
==7355==ERROR: AddressSanitizer: SEGV on unknown address 0x000000000004 (pc 0x0000008f9bfe bp 0x7ffea000f9f0 sp 0x7ffea000f600 T0)
==7355==The signal is caused by a READ memory access.
==7355==Hint: address points to the zero page.
    #0 0x8f9bfe in gf_media_make_isma/programs/mp4box/builds/build10/src/media_tools/isom_tools.c:445:37
    #1 0x4e4934 in mp4boxMain/programs/mp4box/builds/build10/applications/mp4box/main.c:6332:8
    #2 0x7f224ff820b2 in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x270b2)
    #3 0x41ea6d in _start (/zhengjie/cmdline-fuzz/programs/mp4box/builds/build10/bin/gcc/MP4Box+0x41ea6d)

AddressSanitizer can not provide additional info.
SUMMARY: AddressSanitizer: SEGV/programs/mp4box/builds/build10/src/media_tools/isom_tools.c:445:37 in gf_media_make_isma
==7355==ABORTING
```
--- end body ---
