Hello,
I have two files - isma (audio) and ismv (video) downloaded with YouTube. Both are DRM protected.
I also have right decryption key.

I have red "Dealing with ISMV and ISMA input files" so I used mp4fragment to fix lack of TFDTs. After fixing audio and video are playing with vlc, but they are obviously encrypted.

Unfortunately decrypting it with mp4decrypt changes nothing. I'm 100% sure that decryption key is correct. I have some experience with decrypting dash files, so I know how to properly use mp4decrypt. There is probably something in procedure, that I'm missing or there is some issue with Bento4 and ism files.

I've also tried to convert ism to dash (mp4dash.bat) and then merging parts binary with python, but there is no change. I still cannot properly decrypt neither audio or video. This method (binary merging and decrypting "native" mpd) works file with other (not ism) files so there is little chance that something is wrong on my side.

Any help would be much appreciated.
Best regards
ism/manifest can't decrypt audio or video
This is a GitHub Issue
repo:Bento4
owner:axiomatic-systems
Title : ism/manifest can't decrypt audio or video
Issue date:

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Hello,
I have two files - isma (audio) and ismv (video) downloaded with YouTube. Both are DRM protected.
I also have right decryption key.

I have red "Dealing with ISMV and ISMA input files" so I used mp4fragment to fix lack of TFDTs. After fixing audio and video are playing with vlc, but they are obviously encrypted.

Unfortunately decrypting it with mp4decrypt changes nothing. I'm 100% sure that decryption key is correct. I have some experience with decrypting dash files, so I know how to properly use mp4decrypt. There is probably something in procedure, that I'm missing or there is some issue with Bento4 and ism files.

I've also tried to convert ism to dash (mp4dash.bat) and then merging parts binary with python, but there is no change. I still cannot properly decrypt neither audio or video. This method (binary merging and decrypting "native" mpd) works file with other (not ism) files so there is little chance that something is wrong on my side.

Any help would be much appreciated.
Best regards
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