playback issue of HEVC content with CENC cbcs encryption in AVplayer

Hi,


We have 4K video conent encoded in HEVC packaged in HLS fmp4. The playback from the AVplayer in an iPad with iOS 13 is fine. However, after CENC cbcs encryption, the playback shows macroblocking issue every 1 or 2seonds. We used Shaka Packager to package or encrypt the 4K content in both cases. Here are the links to the sample conent:

Clear (playback is OK):

https://hls-demo-s3.s3.us-east-2.amazonaws.com/4k_cbcs_testing/3/video.m3u8

Encrypted (playback has macroblocking issue):

https://hls-demo-s3.s3.us-east-2.amazonaws.com/4k_cbcs_testing/4/video.m3u8


Can some one help to see what the problem could be?


Thanks.