HLS - HEVC 1080/2160 25/50 frames issues with DRM

Hi all,

I'm streaming in HEVC 1080/2160 25/50 frames to Apple TV 4K 1st Gen. In both cases the devices can display the content without major issue, even doing HEVC 2160p50 which is very intense on the CPU, so the devices is very capable of handling that.

Problem begins as soon i enabled DRM Fairplay, Apple TV presents some sporadic video freezing and apple tv console logs shows "dropped frames" as the main reason for it.

The bigger the resolution and frame rate has more often video freezing. Even doing HEVC 720p50 there are some ocurrences. Did not have any ocurrence doing 576p50. It seems to be an issue related to pure CPU of decoding and decryption of the content, but afaik the Apple TV has an independent chipset just for decription.

Is this a known issue? Any ideas what could it be? Why DRM/Fairplay enabled could affect that much the performance?

Looking forward to the replies. Thanks!

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fgutierrezwalton
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There's a good chance that there are one or more problems with the way that you're encrypting your content, and that's triggering decode errors on the Apple TV. If you look at the console log on the device, it may be reporting these decode errors.

It would be a good idea to follow the instructions here to verify the validity of your streams: https://developer.apple.com/library/archive/technotes/tn2454/_index.html

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Media Engineer
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Thanks for your reply.

I will go through the test from that link you shared, but i do not believe is a key DRM error as the content can be decrypted correctly. Dropped frames start showing up after around 4-5 minutes of smooth playback. I'm not using IV as you can see in the following EXT-X-KEY from my URLs.

#EXT-X-KEY:METHOD=SAMPLE-AES,URI="skd://private.com/streaming/getckc?AccountId=lgilab5aitc&CrmId=lgilab5aitc&ContentId=PRIVATE&KeyId=6d10b094-f812-3cc8-a7d5-82c69ba07ff2",KEYFORMAT="com.apple.streamingkeydelivery",KEYFORMATVERSIONS="1"

Also as i mention before, lower resolutions on HEVC do playback correctly. AVC do playback correctly on 1080p50, all are encrypted in the same way compare to the HEVC streams, using the same content ID, etc.

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fgutierrezwalton
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Hello, I'm a Apple HLS developer and have similar issue with you.

On my side, the situation is that 4K HEVC with 50 frames Fairplay video is always suttering every few seconds during playback, but the thing will change if decreasing the frame rate to 30 frames or decreasing the video resolution.

We suppose that the stuttering phenomenon has a strong relationship with encrypted data volume.

HAVE YOU FIXED YOUR ISSUE OR HAD ANY IDEAS ABOUT IT?

Many thanks.

Posted by
QiaoyuGu
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