Open to closed group of pictures conversion in interframe video compression

A computer program product comprising:

• a non-transitory computer-readable medium with computer program instructions encoded thereon, wherein the computer program instructions, when processed by a computer, instruct the computer to perform a method of converting an open group of pictures (GOP) used in interframe video compression into a Closed GOP, the method comprising:
• receiving an encoded bitstream that has been encoded using Open GOP interframe video compression;
• extracting a first Open GOP from the bitstream;
• decoding at least part of the first Open GOP to generate a first group of uncompressed frames of video;
• extracting a second Open GOP sequentially following the first Open GOP in the bitstream, wherein the extracted second GOP comprises a series of encoded frames including an intra-coded picture (I frame);
• referring to at least one frame of the first group of uncompressed frames, decoding at least a part of the second Open GOP to generate a second group of uncompressed frames of video;
• re-encoding the second group of uncompressed frames to generate a re-encoded second GOP comprising one or more re-encoded bipredictive coded pictures (B frames) having a display order preceding an I frame of the second GOP, the re-encoded B frames being re-encoded with reference to a frame generated by decompressing the I frame of the second GOP as received in the bitstream and without reference to a frame of the first Open GOP;
• converting the second Open GOP to a corresponding Closed GOP, the Closed GOP comprising:
• the one or more re-encoded B frames;
• the I frame of the second GOP as received in the encoded bitstream, wherein the encoder flags the I frame of the second GOP as received in the encoded bitstream as an instantaneous decoder refresh (IDR) frame;
• and
• encoded data as received in the encoded bitstream for each frame of the second GOP that is displayed sequentially following the I frame of the second GOP.