DRM protected videos are playing in non-secure mode in few devices

[sharish]

Version

Media3 1.4.0

More version details

Issue

Since 1.4.0-alpha01, the DRM protected videos are playing in non-secure mode in few devices.

Why?

On Commit c872af4 -> We removed mediaCryptoRequiresSecureDecoder on MCR (MediaCodecRenderer) from field variable to local variable.

However the problem began on how we initialized the variable. Before this commit, the mediaCryptoRequiresSecureDecoder is initialized by following (Refer: MCR#1047)

mediaCryptoRequiresSecureDecoder =
          !frameworkCryptoConfig.forceAllowInsecureDecoderComponents
              && mediaCrypto.requiresSecureDecoderComponent(checkStateNotNull(mimeType));

But now, the initialization is happening based on codecDrmSession with the following code (Refer MCR#551)

boolean mediaCryptoRequiresSecureDecoder =
            codecDrmSession != null
                && codecDrmSession.requiresSecureDecoder(
                    checkStateNotNull(inputFormat.sampleMimeType));

The interesting point to note is the variable name is not changed to codecDrmSessionRequiresSecureDecoder with this change in initialisation but retained as mediaCryptoRequiresSecureDecoder even though initialisation is not done through MediaCrypto.

Note

The issue is not happening on all the devices but only few devices. The devices I noticed the issue are
Motorola G34 on Android 14
OnePlus Nord CE 3 Lite 5G on Android 13 (CPH2467)

Impact

1. The devices are playing in non-secure mode - Causing screenshots are not being blacked out
2. The playback at high speeds are stuttering.

Questions?

1. Why does codecDrmSession.requiresSecureDecoder("video/avc") and mediaCrypto.requiresSecureDecoderComponent("video/avc") are not same on these devices? In fact Motorola G34 is a stock android where the issue happens. Does that mean it is a hardware level issue?

2. Why do we have two function (mediaCrypto.requiresSecureDecoderComponent and codecDrmSession.requiresSecureDecoder) in two different classes if the purpose is same?

3. How does secureness of the codec impact the audio playback? In both secure and non-secure mode, the codec initialised is the same hardware codec but in secure mode no stuttering is seen, but in non-secure mode stuttering is seen

Devices that reproduce the issue

Motorola G34 on Android 14
OnePlus Nord CE 3 Lite 5G on Android 13 (CPH2467)

Devices that do not reproduce the issue

Pixel 8 Pro on Android 14
OnePlus Pad on Android 14 (OPD2203)

Reproducible in the demo app?

Yes

Reproduction steps

1. Check out demo app with commit c872af4
2. Build the app and run the demo app on mentioned reproducible devices
3. In demo app, Expand Widevine DASH (MP4, H264)
4. Play HD (cenc) video
5. Execute the adb command adb shell dumpsys media.resource_manager
6. Take a screenshot

Expected result

At Step5, The expected codec attached is secure

Output of adb command ( In device CPH2467 on android 13)

      Client:
        Id: -5476376607769517440
        Name: c2.qti.avc.decoder.secure
        Resources:
          secure-codec/video-codec:[]:1
          battery/video-codec:[]:1

At Step6, The screenshot should be blacked-out (showcasing secureness)

Actual result

At Step5, The actual codec attached is non-secure

Output of adb command ( In device CPH2467 on android 13)

      Client:
        Id: -5476376610050332288
        Name: c2.qti.avc.decoder
        Resources:
          non-secure-codec/video-codec:[]:1
          battery/video-codec:[]:1

At Step6, The screenshot show the playback of video (showcasing insecure)

Media

Widevine DASH(MP4, H264) > HD (cenc)

Bug Report

• You will email the zip file produced by adb bugreport to [email protected] after filing this issue.

[icbaker]

Thanks for reporting - would you be able to run the following code on the devices that do and don't reproduce the issue, and let us know the results?

try (MediaDrm mediaDrm = new MediaDrm(C.WIDEVINE_UUID)) {
  Log.w(
    "issue-1603", 
    "MediaDrm[version]=" 
        + mediaDrm.getPropertyString("version")
        + ", MediaDrm[oemCryptoApiVersion]=" 
        + mediaDrm.getPropertyString("oemCryptoApiVersion"));
} 

We have a hypothesis this might be related to the Widevine plug-in implementation underneath MediaDrm but having the version numbers would help confirm this.

[sharish]

Here are the logs:

Devices that reproduce the issue

Device	OS	Log info
Moto G34	Android 14	MediaDrm[version]=16.0.1@001, MediaDrm[oemCryptoApiVersion]=16
OnePlus Nord CE 3 Lite 5G	Android 13	MediaDrm[version]=16.0.0, MediaDrm[oemCryptoApiVersion]=16

Devices that do not reproduce the issue

Device	OS	Log info
Pixel 8 Pro	Android 14	MediaDrm[version][email protected], MediaDrm[oemCryptoApiVersion]=18
OnePlus Pad	Android 14	MediaDrm[version]=16.1.1@006, MediaDrm[oemCryptoApiVersion]=16

[icbaker]

Thanks for the additional information. I think there are two related, but separate, issues here:

1. MediaDrm.requiresSecureDecoder incorrectly returns false for Widevine on version=16.0 (and earlier). It works correctly from version=16.1. I have an internal change under review to check the version in FrameworkMediaDrm before relying on this method.
2. You seem surprised that your content can be played without Widevine L1 hardware secure playback. If this is a concern then you should enforce this restriction in your license policy. This part isn't a bug in ExoPlayer or the DRM framework.
   • Note: If you had L1 enforced in your license you would likely see a Operation not supported in this configuration: ERROR_DRM_CANNOT_HANDLE error currently, due to (1).
   • If you're a Widevine partner you can also get support for correctly configuring your license policy directly from them: https://www.widevine.com/contact.

[sharish]

Thanks for the details @icbaker.

We have L1 enforcement through our widevine partners and I feel that is not the issue. My question was

When the video plays in non-secure-codec mode, the audio stutters a lot while the same in secure-codec, it is playing fine. I'm aware about the buffer-underflow issue the devices generally faces for stuttering, however this seems to be a peculiar way for a device to stutter. If you have any insights on why devices stutter in 'non-secure-codec but hardwareAccelaration enbled codecs', it will be a great learning.

Thanks in advance.

[icbaker]

I'm afraid we don't have info on the device-specific behaviours of the different codecs - but I think your issue should be resolved once we stop relying on MediaDrm.requiresSecureDecoder on CDM version 16.0.0.

[rbugajewski]

@icbaker Thanks for confirmation. After we upgraded to 1.4.0 we are also seeing this issue on certain devices. I ran a debug session today, and got the following output on a Samsung Galaxy Tab A8 (Android 14):

MediaDrm[version]=16.0.1@005, MediaDrm[oemCryptoApiVersion]=16

This would confirm your hypothesis that the underlying plug-in implementation could be responsible.

[icbaker]

The workaround for this issue is linked above. This should be included in the 1.4.1 release.