Reformatting media streams to include auxiliary data

Abstract

Reformatting a media stream to include auxiliary data, the method including: receiving the auxiliary data to be inserted into the media stream; determining the amount of data in the auxiliary data; identifying media data in the media stream to be reduced in size; reformatting the media stream to reduce the amount of data in the media data such that the amount of data removed from the media data is at least equal to the amount of data in the auxiliary data while providing minimal impact to the quality of the media data; and adding the auxiliary data to the media stream which maintains a consistent size.

The invention claimed is: 
     
       1. A method to reformat a media stream to include auxiliary data, the method comprising:
 receiving the auxiliary data to be inserted into the media stream; 
 determining the amount of data in the auxiliary data; 
 identifying media data in the media stream to be reduced in size; 
 reformatting the media stream to reduce the amount of data in the media data such that the amount of data removed from the media data is at least equal to the amount of data in the auxiliary data while providing minimal impact to the quality of the media data; and 
 adding the auxiliary data to the media stream which maintains a consistent size; 
 wherein reformatting the media stream comprises generating and sorting DCT coefficients of the blocks in the frames by impact on visual quality of the media data to produce a sorted list; and removing the DCT coefficients with largest values in the sorted list that would remove enough data from the media data to accommodate the amount of data in the auxiliary data. 
 
     
     
       2. The method of  claim 1 , wherein the auxiliary data includes a target location in the media stream as a byte location in the media stream to indicate a location for an insertion of an entitlement control message (ECM). 
     
     
       3. The method of  claim 1 , further comprising
 applying adjustment to maintain consistency in the media stream, 
 wherein the adjustment is made to data between the removed media data and the added auxiliary data. 
 
     
     
       4. The method of  claim 3 , wherein the consistency in the media stream provides playback of the media data without artifacts including jitter, skips, and frozen playback. 
     
     
       5. The method of  claim 1 , wherein the removed media data is video data, and
 wherein reformatting the media stream to reduce the amount of data in the media data comprises 
 removing an entire B frame of the video data. 
 
     
     
       6. The method of  claim 1 , wherein reformatting the media stream to reduce the amount of data in the media data comprises
 re-encoding elements of at least one of frames, slices and macro-blocks using a higher quantization value. 
 
     
     
       7. The method of  claim 6 , wherein the elements are re-encoded in groups to distribute a quality loss over a larger area. 
     
     
       8. The method of  claim 1 , further comprising
 identifying a location of the media data to be removed by earliest and latest locations of the auxiliary data, and identifying blocks in frames that are in the location of the media data to be removed. 
 
     
     
       9. The method of  claim 1 , further comprising setting the DCT coefficients corresponding to highest frequencies to zero; and applying Huffman encoding to re-encode the blocks. 
     
     
       10. The method of  claim 1 , wherein the removed media data is encoded in macro-blocks with prediction information. 
     
     
       11. The method of  claim 1 , wherein the auxiliary data includes digital right management (DRM) information. 
     
     
       12. The method of  claim 11 , wherein the DRM information includes
 MPEG-2 entitlement management messages and entitlement control messages. 
 
     
     
       13. The method of  claim 1 , wherein the media stream is in an MPEG-2 transport stream format. 
     
     
       14. A system for reformatting a media stream to include auxiliary data, the system comprising:
 a head end server configured to receive the auxiliary data to be inserted into the media stream through a first network, the head end server determining the amount of data in the auxiliary data, identifying media data to be reduced in size in the media stream, and reformatting the media stream to reduce the amount of data in the media data such that the amount of data removed from the media data is at least equal the amount of data in the auxiliary data while providing minimal impact to the quality of the media data; and 
 a network interface module configured to add the auxiliary data to the reformatted media stream and distribute the media stream to a plurality of client devices through a second network while the media stream maintains a consistent size; 
 wherein reformatting the media stream comprises generating and sorting DCT coefficients of the blocks in the frames by impact on visual quality of the media data to produce a sorted list; and removing the DCT coefficients with largest values in the sorted list that would remove enough data from the media data to accommodate the amount of data in the auxiliary data. 
 
     
     
       15. The system of  claim 14 , wherein the auxiliary data includes digital right management (DRM) information. 
     
     
       16. A non-transitory storage medium storing a computer program to reformat a media stream to include auxiliary data, the computer program comprising executable instructions which cause the computer to:
 receive the auxiliary data to be inserted into the media stream; 
 determine the amount of data in the auxiliary data; 
 identify media data to be reduced in size; 
 reformat the media stream to reduce the amount of data in the media data such that the amount of data removed from the media data is at least equal to the amount of data in the auxiliary data while providing minimal impact to the quality of the media data; and 
 add the auxiliary data to the media stream which maintains a consistent size; 
 wherein executable instructions that cause the computer to reformat the media stream comprise executable instructions which cause the computer to generate and sort DCT coefficients of the blocks in the frames by impact on visual quality of the media data to produce a sorted list; and remove the DCT coefficients with largest values in the sorted list that would remove enough data from the media data to accommodate the amount of data in the auxiliary data. 
 
     
     
       17. The non-transitory storage medium of  claim 16 , wherein executable instructions that cause the computer to identify media data to be removed comprise executable instructions which cause the computer to
 identify blocks in frames that are in a location of the media data to be removed. 
 
     
     
       18. The non-transitory storage medium of  claim 16 , further comprising executable instructions which cause the computer to set the DCT coefficients corresponding to highest frequencies to zero; and apply Huffman encoding to re-encode the blocks.