We have successfully compiled the gpac on ARM/ARM_V7/x86 using Android NDK.
We created a new Android Studio 4.1 project compatible with the newest Android tools, by following the **mp4box_android** sample project.
The new Android project can be downloaded from [here](https://drive.google.com/file/d/1R0iV5oK9KSArBYV0CsFCU1CYwXQ9RBrp/view?usp=sharing).

We granted the **write_external_storage** runtime permission and set `android:requestLegacyExternalStorage="true"` in the AndroidManifest.xml since we are using `compileSdkVersion 30`

We added the sample video onto device file within the Android Download folder [legend.mp4](https://drive.google.com/file/d/122-BJc9lJOHssyM_hLFHObi8XrZlHgoT/view?usp=sharing)

Within the Android app we have tried to load successfully all the .so libs compiled
Within the Android project we have tried to execute the following command for mp4box: "`MP4Box -frag 240000 /storage/emulated/0/Download/legend.mp4 -out /storage/emulated/0/Download/legend_frag.mp4`"
We get the following console output:
```
2021-02-28 13:26:29.592 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::start
2021-02-28 13:26:29.593 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::command get back ok
2021-02-28 13:26:29.593 9274-9349/com.enst.mp4box V/WRAPPER_JNI: Convert command line done
2021-02-28 13:26:29.622 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::end
```
**Current** result:
 - no output video file 
 
**Expected** result:
 - /storage/emulated/0/Download/legend_frag.mp4 should be created

We have tried different command lines but with no good result. 
One thing I have to note here, when doing -frag or some other command lines, the terminal should pop the message `WRAPPER_JNI: mp4terminal::end` only after ~10seconds since the video processing takes a while, depending of how long the input video is. Currently `mp4terminal::end` comes right after `mp4terminal::start` no matter which command line is executed

Moreover we put the .so files in the osmo4 project and is working fine
[Need Info] Android MP4box command line seems to do nothing
This is a GitHub Issue
repo:gpac
owner:gpac
Title : [Need Info] Android MP4box command line seems to do nothing
Issue date:

--- start body ---
We have successfully compiled the gpac on ARM/ARM_V7/x86 using Android NDK.
We created a new Android Studio 4.1 project compatible with the newest Android tools, by following the **mp4box_android** sample project.
The new Android project can be downloaded from [here](https://drive.google.com/file/d/1R0iV5oK9KSArBYV0CsFCU1CYwXQ9RBrp/view?usp=sharing).

We granted the **write_external_storage** runtime permission and set `android:requestLegacyExternalStorage="true"` in the AndroidManifest.xml since we are using `compileSdkVersion 30`

We added the sample video onto device file within the Android Download folder [legend.mp4](https://drive.google.com/file/d/122-BJc9lJOHssyM_hLFHObi8XrZlHgoT/view?usp=sharing)

Within the Android app we have tried to load successfully all the .so libs compiled
Within the Android project we have tried to execute the following command for mp4box: "`MP4Box -frag 240000 /storage/emulated/0/Download/legend.mp4 -out /storage/emulated/0/Download/legend_frag.mp4`"
We get the following console output:
```
2021-02-28 13:26:29.592 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::start
2021-02-28 13:26:29.593 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::command get back ok
2021-02-28 13:26:29.593 9274-9349/com.enst.mp4box V/WRAPPER_JNI: Convert command line done
2021-02-28 13:26:29.622 9274-9349/com.enst.mp4box V/WRAPPER_JNI: mp4terminal::end
```
**Current** result:
 - no output video file 
 
**Expected** result:
 - /storage/emulated/0/Download/legend_frag.mp4 should be created

We have tried different command lines but with no good result. 
One thing I have to note here, when doing -frag or some other command lines, the terminal should pop the message `WRAPPER_JNI: mp4terminal::end` only after ~10seconds since the video processing takes a while, depending of how long the input video is. Currently `mp4terminal::end` comes right after `mp4terminal::start` no matter which command line is executed

Moreover we put the .so files in the osmo4 project and is working fine
--- end body ---

None