Patent ID: 7346163

Claim:
A method of processing digital video content in a video-on-Demand (VOD) system, wherein the digital video content comprises unencrypted intra-coded frames and inter-coded frames, the method comprising: duplicating the unencrypted intra-coded frames; selecting a plurality of the unencrypted intra-coded frames for encryption to produce selected frames; encrypting the selected frames under a first encryption algorithm to produce first encrypted frames; encrypting the duplicates of the unencrypted selected frames under a second encryption algorithm to produce second encrypted frames; storing the inter-coded frames in a first file; storing the intra-coded frames, whether encrypted under the first encryption algorithm or unencrypted, in a second file; and storing the duplicate intra-coded frames, whether encrypted under the second encryption algorithm or unencrypted, in a third file; sending normal play content to a receiver compatible with the first encryption algorithm by multiplexing content from the first file with content from the second file, sending trick play content to a receiver compatible with the first encryption algorithm by retrieving content only from the second file; sending normal play content to a receiver compatible with the second encryption algorithm by multiplexing content from the first file with content from the third file, sending trick play content to a receiver compatible with the second encryption algorithm by retrieving content only from the third file; whereby, separate trick play files and multiple encrypted content files are combined.