Peace be upon you and God's mercy and blessings.
Grand Ayatollah Sayyid Sistani (may God protect him):
His approval or disapproval has no effect except within the framework of laws that regulate the rights of authors, publishers, and their counterparts, and which are endorsed by the legitimate authority. It is important to note that His Eminence does not permit violating the aforementioned laws that are followed in Islamic countries.
Moreover, it is not permissible if it involves acting upon his property, such as if the lecture is recorded on a disk owned by the lecturer, for example.
Source: Official website
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Grand Ayatollah Sayyid Khamenei (may God protect him):
It is strongly recommended not to use intellectual products without the permission of their owners or knowledge of their consent, even in the case presented in the question.
May you be successful in all good.