Peace be upon you. According to Grand Ayatollah Sayyid Sistani (may Allah protect him), the professor's consent or lack thereof only matters within the framework of laws that regulate the rights of authors and publishers, which must be endorsed by the legal authority. It is important to note that Sayyid Sistani does not permit violating the laws in place in Islamic countries. Additionally, it is not permissible to act upon their property, such as if the lecture is recorded on a disk owned by the lecturer. Grand Ayatollah Sayyid Khamenei (may Allah protect him) states that it is strongly recommended to refrain from using intellectual products without the permission of their owners or without knowing their consent, even in this case. May you be successful in all good.