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

- [ /] I looked for a similar issue and couldn't find any.
- [ /] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [/ ] 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

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

Using the GPAC testsuite file tpl_roll.xml to generate and dash media:

```
mp4box.exe -crypt D:\git-repos\gpac\testsuite\media\encryption\tpl_roll.xml D:\test.mp4 -out tpl_roll.mp4

mp4box.exe -rap -dash 2000 -bs-switching no -profile live -pssh v -out .\tpl_roll\index.mpd -sample-groups-traf -no-frags-default -tfdt-traf --cmaf=cmfc -single-traf tpl_roll.mp4 -segment-name $Segment=seg_r$$Init=seg-init_r$$RepresentationID$-$Number$
```

The MPD contains:

`<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" value="cbcs" cenc:default_KID="27992649-6a7f-5d25-da69-f2b3b2799a7f"/>`

According to DASH-IF IOP-6 V5.0.0 sect 9.3 In-band key rotation signalling

> "For supporting this mechanism:
> • The MPD has no default_KID attribute in the ContentProtection element defined at the AdaptationSet level [...]"

so I think the cenc:default_KID should not be present?

tpl_roll: mp4box is putting default KID in the MPD
This is a GitHub Issue
repo:gpac
owner:gpac
Title : tpl_roll: mp4box is putting default KID in the MPD
Issue date:

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

- [ /] I looked for a similar issue and couldn't find any.
- [ /] I tried with the latest version of GPAC. Installers available at http://gpac.io/downloads/gpac-nightly-builds/
- [/ ] 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

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

Using the GPAC testsuite file tpl_roll.xml to generate and dash media:

```
mp4box.exe -crypt D:\git-repos\gpac\testsuite\media\encryption\tpl_roll.xml D:\test.mp4 -out tpl_roll.mp4

mp4box.exe -rap -dash 2000 -bs-switching no -profile live -pssh v -out .\tpl_roll\index.mpd -sample-groups-traf -no-frags-default -tfdt-traf --cmaf=cmfc -single-traf tpl_roll.mp4 -segment-name $Segment=seg_r$$Init=seg-init_r$$RepresentationID$-$Number$
```

The MPD contains:

`<ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" value="cbcs" cenc:default_KID="27992649-6a7f-5d25-da69-f2b3b2799a7f"/>`

According to DASH-IF IOP-6 V5.0.0 sect 9.3 In-band key rotation signalling

> "For supporting this mechanism:
> • The MPD has no default_KID attribute in the ContentProtection element defined at the AdaptationSet level [...]"

so I think the cenc:default_KID should not be present?

--- end body ---

The issue describes a potential non-compliance with the DASH-IF IOP-6 specification regarding the use of the default_KID attribute in the MPD (Media Presentation Description). The user indicates that the MPD generated by mp4box includes a default_KID attribute, which should not be present according to the specification when in-band key rotation signaling is supported. This could lead to compatibility issues with DASH players that strictly adhere to the specification.