CORRECTION:
Some older Amazon Prime Video is still FLV/H.264 while some newer video is FlashAccess DRM AES-encrypted as documented above. A show may be split where season 1 is unencrypted and season two is encrypted.
I encountered this for the first time yesterday where season 1 was unencrypted, could be downloaded, playable and converted while season 2 was encrypted, could be downloaded, was NOT playable and could NOT be converted.
(Anagram of the show to thwart search engines)
http://epguides.com/theruL/
FlashAccess is becoming more prevalent so the community should marshall its resources and combat this new DRM!
Regards,
heyadam