Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [X] I looked for a similar issue and couldn't find any.
- [X] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95
- [X] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

I use gpac to cut a mp4 file into ll-hls files and use nginx to serve them. gpac command I used is:
```shell
gpac -i ~/Videos/436256398-1-208.mp4  -o res/playlist.m3u8:gpac:segdur=6:cdur=1:profile=live:dmode=dynamic:rdirs=outdir:llhls=sf
```
I use https://www.theoplayer.com/ll-hls-test-page to verify ll-hls and find that the video is playing for 2~3s then it starts buffering infinitly. I use sample ll-hls test url and it can play normally and I believe that bandwidth is not bottleneck because I run nginx on  `localhost`.
I try to build `gpac` by myself, also try to use latest nightly prebuilded version of `gpac`  on [gpac official site](gpac.io) on Ubuntu 18.04, but this question still happpen. I want to know why and how to fix this question. 
gpac generated ll-hls files cannot play normally
This is a GitHub Issue
repo:gpac
owner:gpac
Title : gpac generated ll-hls files cannot play normally
Issue date:

--- start body ---
Thanks for reporting your issue. Please make sure these boxes are checked before submitting your issue - thank you!

- [X] I looked for a similar issue and couldn't find any.
- [X] I give enough information for contributors to reproduce my issue (meaningful title, github labels, platform and compiler, command-line ...). I can share files anonymously with this dropbox: https://www.mediafire.com/filedrop/filedrop_hosted.php?drop=eec9e058a9486fe4e99c33021481d9e1826ca9dbc242a6cfaab0fe95da5e5d95
- [X] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/

Detailed guidelines: http://gpac.io/2013/07/16/how-to-file-a-bug-properly/

I use gpac to cut a mp4 file into ll-hls files and use nginx to serve them. gpac command I used is:
```shell
gpac -i ~/Videos/436256398-1-208.mp4  -o res/playlist.m3u8:gpac:segdur=6:cdur=1:profile=live:dmode=dynamic:rdirs=outdir:llhls=sf
```
I use https://www.theoplayer.com/ll-hls-test-page to verify ll-hls and find that the video is playing for 2~3s then it starts buffering infinitly. I use sample ll-hls test url and it can play normally and I believe that bandwidth is not bottleneck because I run nginx on  `localhost`.
I try to build `gpac` by myself, also try to use latest nightly prebuilded version of `gpac`  on [gpac official site](gpac.io) on Ubuntu 18.04, but this question still happpen. I want to know why and how to fix this question. 
--- end body ---
