CMAF playback with key rotation

[ashish157]

Hi All,
Im trying to enable support for key rotation in CMAF. The media segments contains an senc box and the saio points to this senc . The playback works without any issues. This was without the sbgp and sgpd boxes. Now since we wanted to add key rotation support to CMAF and as per the understanding we were forced to add sbgp and sgpd boxes to provide the new KID's. In this case:

• Should the saio box point to the senc or sgpd/sbgp ?

With saio pointing to senc and the media segments just containing sgpd/sbgp + pssh boxes with new KID's, here is my observation with dash.js player:

1. Player requests the init and media segment (200 OK), then
2. Player requests license (200 OK)
3. No playback and the player stops requesting further segments.

Since we are doing key rotation, we are adding all 0's in tenc > default KID, but adding the actual KID in the pssh box as well as the sgpd box in media segment.
To verify if it is the correct KID with which the segment is encrypted I extracted the KID from segment and manually decrypted the segment. The init + this segment playback works fine.

Is there anything missing?

[dsilhavy]

Can you share the teststream?

[ashish157]

Hi @dsilhavy , unfortunately I cant share the teststream but is it ok if I share the media segments ?

[dsilhavy]

In the end I need an MPD to check this in dash.js. Can you share the stream privately with me?

[ashish157]

ok, let me find a way to do it. I'm also trying to understand whether saio should point to senc or sgpd in case if both boxes are present in media segments. Any idea ?

[ashish157]

@dsilhavy I have managed to create an asset which also has same problem. The playback stops exactly at 9 sec mark. I created the asset using shaka-packager. Here are the URL's:

Playback URL: https://raw.githubusercontent.com/ashish157/testdata/main/stream.mpd
Widevine License URL: https://widevine-proxy.appspot.com/proxy

Can you please check ?