private static unsafe IntPtr MarshalSubsampleArray(EncryptedPacket packet)
{
var subsamplePointer = IntPtr.Zero;
if (packet.Subsamples != null)
{
var subsamples = packet.Subsamples.Select(o => new MSD_SUBSAMPLE_INFO {
uBytesOfClearData = o.ClearData, uBytesOfEncryptedData = o.EncData
}).ToArray();
var totalSize = Marshal.SizeOf(typeof(MSD_SUBSAMPLE_INFO)) * subsamples.Length;
var array = Marshal.AllocHGlobal(totalSize);
var pointer = (MSD_SUBSAMPLE_INFO *)array.ToPointer();
for (var i = 0; i < subsamples.Length; i++)
{
pointer[i] = subsamples[i];
}
subsamplePointer = (IntPtr)pointer;
}
var subData = new MSD_FMP4_DATA
{
uSubSampleCount = (uint)(packet.Subsamples?.Length ?? 0),
pSubSampleInfo = subsamplePointer
};
var subdataPointer = Marshal.AllocHGlobal(Marshal.SizeOf(subData));
Marshal.StructureToPtr(subData, subdataPointer, false);
return(subdataPointer);
}
private unsafe eCDMReturnType CreateParamsAndDecryptData(EncryptedPacket packet, byte *data, int dataLen, ref HandleSize[] pHandleArray, CancellationToken token)
{
fixed(byte *iv = packet.Iv, kId = packet.KeyId)
{
var subdataPointer = MarshalSubsampleArray(packet);
var subsampleInfoPointer = ((MSD_FMP4_DATA *)subdataPointer.ToPointer())->pSubSampleInfo;
try
{
var param = new sMsdCipherParam
{
algorithm = eMsdCipherAlgorithm.MSD_AES128_CTR,
format = eMsdMediaFormat.MSD_FORMAT_FMP4,
pdata = data,
udatalen = (uint)dataLen,
piv = iv,
uivlen = (uint)packet.Iv.Length,
pkid = kId,
ukidlen = (uint)packet.KeyId.Length,
psubdata = subdataPointer
};
return(DecryptData(new[] { param }, ref pHandleArray, packet.StreamType, token));
}
finally
{
if (subsampleInfoPointer != IntPtr.Zero)
{
Marshal.FreeHGlobal(subsampleInfoPointer);
}
Marshal.FreeHGlobal(subdataPointer);
}
}
}
private Packet DecryptPacketOnIemeThread(EncryptedPacket packet, CancellationToken token)
{
// Do padding only for Widevine with keys shorter then 16 bytes
// Shorter keys need to be zero padded, not PCKS#7
if (DrmType == EmeUtils.DrmType.Widevine && packet.Iv.Length < 16)
{
packet.Iv = PadIv(packet.Iv);
}
var pHandleArray = new HandleSize[1];
var ret = CreateParamsAndDecryptData(packet, ref pHandleArray, token);
if (ret == eCDMReturnType.E_SUCCESS)
{
return(new DecryptedEMEPacket(thread)
{
Dts = packet.Dts,
Pts = packet.Pts,
StreamType = packet.StreamType,
IsKeyFrame = packet.IsKeyFrame,
Duration = packet.Duration,
HandleSize = pHandleArray[0]
});
}
Logger.Error($"Decryption failed: {packet.StreamType} - {ret}");
throw new DrmException($"Decryption failed: {packet.StreamType} - {ret}");
}
private unsafe eCDMReturnType CreateParamsAndDecryptData(EncryptedPacket packet, ref HandleSize[] pHandleArray, CancellationToken token)
{
switch (packet.Storage)
{
case IManagedDataStorage managedStorage:
fixed(byte *data = managedStorage.Data)
return(CreateParamsAndDecryptData(packet, data, managedStorage.Data.Length, ref pHandleArray, token));
case INativeDataStorage nativeStorage:
return(CreateParamsAndDecryptData(packet, nativeStorage.Data, nativeStorage.Length, ref pHandleArray, token));
default:
throw new DrmException($"Unsupported packet storage: {packet.Storage?.GetType()}");
}
}
public async Task <Packet> DecryptPacket(EncryptedPacket packet, CancellationToken token)
{
ThrowIfDisposed();
return(await thread.Factory.Run(() => DecryptPacketOnIemeThread(packet, token)));
}