Hello,

I have a problem with hls playlists,I don't know if this is a bug, or if I am missing an option somewhere.

I tested with 1.0.1, and the last master version.

I tested this command
```bash 
MP4Box -dash 4000 \
-profile onDemand \
transcoded_720.mp4#video \
transcoded_720.mp4#audio \
-out manifest.m3u8
```
I tried with the gpac tool directly too.

The resulting playlist is playable with vlc and ffplay for example.
But it fails with videojs or hls.js, only the first segment is played.

Here is the resulting playlist for the video track:
```
#EXTM3U
#EXT-X-TARGETDURATION:4
#EXT-X-VERSION:6
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-MAP:URI="transcoded_720_track1__dashinit.mp4",BYTERANGE="960@0"
#EXTINF:4
#EXT-X-BYTERANGE:930114@960
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:743971@931074
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:314098@1675045
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:344031@1989143
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:624362@2333174
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:531460@2957536
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:659193@3488996
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:1333882@4148189
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:711408@5482071
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:293016@6193479
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:447909@6486495
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:246451@6934404
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:314745@7180855
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:544987@7495600
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:514508@8040587
transcoded_720_track1__dashinit.mp4
#EXTINF:2.28
#EXT-X-BYTERANGE:258588@8555095
transcoded_720_track1__dashinit.mp4

#EXT-X-ENDLIST
```

If I analyze the file with your tool at https://gpac.github.io/mp4box.js/test/filereader.html,
In the segment view I get:

| Segment | referenced_size | segment offset |
|---------|-----------------|---------------|
| 0	 |  930114 |   1836    |
| 1	 |  743971 |   931950  |
| 2	 |  314098 |   1675921 |
| 3	 |  344031 |   1990019 |
| 4	 |  624362 |   2334050 |
| 5	 |  531460 |   2958412 |
| 6	 |  659193 |   3489872 |
| 7	 |  1333882 |   4149065 |
| 8	 |  711408 |   5482947 |
| 9	 |  293016 |   6194355 |
| 10 |  447909 |	 6487371 |
| 11 |  246451 |	 6935280 |
| 12 |  314745 |	 7181731 |
| 13 |  544987 |	 7496476 |
| 14 |  514508 |	 8041463 |
| 15 |  258588 |	 8555971 |

From what I see the segment offset from the online tool doesn't match with the byte range offsets in the playlist.
It seems to be missing 876 bytes for each range in the playlist.
If I replace the byte range starting offsets in the playlist with the ones reported by the online tool it works again 
with videojs and hls.js.

Here is the xml mp4 box dump of the file:
[gpac.md](https://github.com/gpac/gpac/files/6915816/gpac.md)

Is it intended to be like that, or is there a specific option to make it work ?

Regards,
Romain

Hls playlist byte range offset doesn't seems right
This is a GitHub Issue
repo:gpac
owner:gpac
Title : Hls playlist byte range offset doesn't seems right
Issue date:

--- start body ---
Hello,

I have a problem with hls playlists,I don't know if this is a bug, or if I am missing an option somewhere.

I tested with 1.0.1, and the last master version.

I tested this command
```bash 
MP4Box -dash 4000 \
-profile onDemand \
transcoded_720.mp4#video \
transcoded_720.mp4#audio \
-out manifest.m3u8
```
I tried with the gpac tool directly too.

The resulting playlist is playable with vlc and ffplay for example.
But it fails with videojs or hls.js, only the first segment is played.

Here is the resulting playlist for the video track:
```
#EXTM3U
#EXT-X-TARGETDURATION:4
#EXT-X-VERSION:6
#EXT-X-MEDIA-SEQUENCE:1
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-MAP:URI="transcoded_720_track1__dashinit.mp4",BYTERANGE="960@0"
#EXTINF:4
#EXT-X-BYTERANGE:930114@960
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:743971@931074
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:314098@1675045
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:344031@1989143
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:624362@2333174
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:531460@2957536
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:659193@3488996
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:1333882@4148189
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:711408@5482071
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:293016@6193479
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:447909@6486495
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:246451@6934404
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:314745@7180855
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:544987@7495600
transcoded_720_track1__dashinit.mp4
#EXTINF:4
#EXT-X-BYTERANGE:514508@8040587
transcoded_720_track1__dashinit.mp4
#EXTINF:2.28
#EXT-X-BYTERANGE:258588@8555095
transcoded_720_track1__dashinit.mp4

#EXT-X-ENDLIST
```

If I analyze the file with your tool at https://gpac.github.io/mp4box.js/test/filereader.html,
In the segment view I get:

| Segment | referenced_size | segment offset |
|---------|-----------------|---------------|
| 0	 |  930114 |   1836    |
| 1	 |  743971 |   931950  |
| 2	 |  314098 |   1675921 |
| 3	 |  344031 |   1990019 |
| 4	 |  624362 |   2334050 |
| 5	 |  531460 |   2958412 |
| 6	 |  659193 |   3489872 |
| 7	 |  1333882 |   4149065 |
| 8	 |  711408 |   5482947 |
| 9	 |  293016 |   6194355 |
| 10 |  447909 |	 6487371 |
| 11 |  246451 |	 6935280 |
| 12 |  314745 |	 7181731 |
| 13 |  544987 |	 7496476 |
| 14 |  514508 |	 8041463 |
| 15 |  258588 |	 8555971 |

From what I see the segment offset from the online tool doesn't match with the byte range offsets in the playlist.
It seems to be missing 876 bytes for each range in the playlist.
If I replace the byte range starting offsets in the playlist with the ones reported by the online tool it works again 
with videojs and hls.js.

Here is the xml mp4 box dump of the file:
[gpac.md](https://github.com/gpac/gpac/files/6915816/gpac.md)

Is it intended to be like that, or is there a specific option to make it work ?

Regards,
Romain

--- end body ---

None