as a rule of thumb, you need to consult within your company legal department to understand if IPP License terms satisfy your requirements. Basically for JPEG or JPEG2000 case there is no any fees associated with their use (unlike for example, MPEG family of codecs), so I think you should be able to use these codecs in your product (consult with your legal department of course).
From our side, I may recommend you to carefully read IPP License available by the link below
What are the license terms and/or license fees for using Intel IPP samples?
Intel IPP samples are provided to show how to use Intel IPP functionality. Some of these samples illustrate the use of Intel IPP in implementing functionality defined by industry standards. These samples are not product-feature-complete codec solutions.
When products are built in accordance to industry standards, there is often intellectual-property licensing involved. Such industry standards are international standards promoted by various standards bodies, such as ISO, ITU-T, and other organizations. When companies produce products in accordance with industry standards, they must ensure that they secure the appropriate technology and intellectual property licensing from the standards bodies and other third parties. Intel IPP material provides pointers to the standards bodies. Industry-standard licensing is not provided as part of Intel IPP, nor is it provided with these example illustrations.
By the way, I'm just curious, why you go from much more featured JPEG2000 format to traditional JPEG in your transcoder, why not in opposite direction? Is that for performance or interchangebility reasons?