No playback for DRM ISM manifest

Hi guys,

I'm writing here a question about a "failed" playback. I'm testing via exoplayer an .ism manifest with clearkey encryption. I don't know whether the problem is related to the lack of support for some codecs or the clearkey support for smoothstreaming, the fact is that for completeness, I tried to use the bento4 tools and without any problems I got positive feedback in reading/decrypting the file.

Here some infos about the content of the manifest:

video codec: FourCC="hvc1"
audio codec: FourCC="AACH" / sometimes FourCC="AACL"

<WRMHEADER
    xmlns="http://schemas.microsoft.com/DRM/2007/03/PlayReadyHeader" version="4.0.0.0">
    <DATA>
        <PROTECTINFO>
            <KEYLEN>16</KEYLEN>
            <ALGID>AESCTR</ALGID>
        </PROTECTINFO>
        <KID>KID_HERE</KID>
        <CHECKSUM>CHECKSUM_HERE</CHECKSUM>
        <LA_URL>URL_HERE</LA_URL>
        <CUSTOMATTRIBUTES>
            <IIS_DRM_VERSION>7.1.1565.4</IIS_DRM_VERSION>
        </CUSTOMATTRIBUTES>
    </DATA>
</WRMHEADER>

If i try to have a playback of this manifest the screen is still black and I get any kind of DRM error.

Here my questions:

Are the above codecs for both audio and video supported?
Can clearkey support then be added for this kind of ism manifest?

Last but not least, i've tried to add the suffix (format=mpd-time-cmaf) at the end of the link without any luck for the playback.

Have you ideas on how to solve this problem?

Any help would be appreciated.