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.m3u8Encrypted (playback has macroblocking issue):https://hls-demo-s3.s3.us-east-2.amazonaws.com/4k_cbcs_testing/4/video.m3u8Can some one help to see what the problem could be?Thanks.
jingke2000
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We want to protect media content in fmp4 format for HLS. The content are encoded in H.264 and H.265. Apple devices need to be supported. So FairPlay/CENC cbcs mode are key DRM methods. Following questions have emeged once we started the development work:1. For H.264 sample encryption, Apple's FairPlay spec says to leave the first 32 bytes of VCL NALU clear (1 byte for VCL NALU type + following 31 bytes). Then pattern (1:9) encryption starts. But in CENC spec (ISO-23001-7:2016), it requires to leave 1 byte for VCL NALU type + slice header to be clear. Then patern (1:9) encryption starts. Which spec should we follow to encrypt h.264 samples in fmp4 format? We think what Apple's FairPlay spec describes is a better method. But we will comply with the standard regardless;2. In Section 9.5.2.2 of ISO-23001-7:2016, it is mentioned that:"Encrypted slice headers were not prohibited in the first edition of this part of ISO/IEC 23001 butwere prohibited by application specifications. A “SHOULD” requirement to leave slice headers unencrypted for‘avc1’ allows possible legacy content with encrypted slice headers to remain conformant to this new edition.But, new content should not encrypt slice headers or it may not decode properly in secure video decoders."Our video codec type is "avc1". Does that mean we are allowed to enctypt the slice headers of video also?3. Where can we find the guidlines fot H.265 encryption by FairPlay/CENC cbcs mode?Thanks!