**Description**
I'm using GPAC to recreate DASH mpd's and HLS playlists. That's to simulate an event from a static asset, or creating a new playlist from 2 individual static assets.

```
gpac --forward=segb -i asset/manifest.mpd -i asset2/manifest.mpd -o merged.mpd:sigfrag:dual
```
```
gpac --forward=segb -i asset/manifest.mpd reframer:rt=on @ -o live.mpd:sigfrag:dynamic:tsb=-1:dual
```
**Expected**
The HLS playlist also contains the directory in the list of individual fragments.

**Actual**
In both cases the resulting HLS playlist for the chunks doesn't contain the `asset` or `asset2` prefix for the individual fragments. It does contain it for the init fragment however.

**Environment**
- macOS Monterey 12.3
- GPAC version 2.0-rev0-g418db414-master
Missing directory in HLS playlist generated from existing MPD
This is a GitHub Issue
repo:gpac
owner:gpac
Title : Missing directory in HLS playlist generated from existing MPD
Issue date:

--- start body ---
**Description**
I'm using GPAC to recreate DASH mpd's and HLS playlists. That's to simulate an event from a static asset, or creating a new playlist from 2 individual static assets.

```
gpac --forward=segb -i asset/manifest.mpd -i asset2/manifest.mpd -o merged.mpd:sigfrag:dual
```
```
gpac --forward=segb -i asset/manifest.mpd reframer:rt=on @ -o live.mpd:sigfrag:dynamic:tsb=-1:dual
```
**Expected**
The HLS playlist also contains the directory in the list of individual fragments.

**Actual**
In both cases the resulting HLS playlist for the chunks doesn't contain the `asset` or `asset2` prefix for the individual fragments. It does contain it for the init fragment however.

**Environment**
- macOS Monterey 12.3
- GPAC version 2.0-rev0-g418db414-master
--- end body ---
