NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Collections About News Help Login
Back to Results
Real-time demonstration hardware for enhanced DPCM video compression algorithmThe lack of available wideband digital links as well as the complexity of implementation of bandwidth efficient digital video CODECs (encoder/decoder) has worked to keep the cost of digital television transmission too high to compete with analog methods. Terrestrial and satellite video service providers, however, are now recognizing the potential gains that digital video compression offers and are proposing to incorporate compression systems to increase the number of available program channels. NASA is similarly recognizing the benefits of and trend toward digital video compression techniques for transmission of high quality video from space and therefore, has developed a digital television bandwidth compression algorithm to process standard National Television Systems Committee (NTSC) composite color television signals. The algorithm is based on differential pulse code modulation (DPCM), but additionally utilizes a non-adaptive predictor, non-uniform quantizer and multilevel Huffman coder to reduce the data rate substantially below that achievable with straight DPCM. The non-adaptive predictor and multilevel Huffman coder combine to set this technique apart from other DPCM encoding algorithms. All processing is done on a intra-field basis to prevent motion degradation and minimize hardware complexity. Computer simulations have shown the algorithm will produce broadcast quality reconstructed video at an average transmission rate of 1.8 bits/pixel. Hardware implementation of the DPCM circuit, non-adaptive predictor and non-uniform quantizer has been completed, providing realtime demonstration of the image quality at full video rates. Video sampling/reconstruction circuits have also been constructed to accomplish the analog video processing necessary for the real-time demonstration. Performance results for the completed hardware compare favorably with simulation results. Hardware implementation of the multilevel Huffman encoder/decoder is currently under development along with implementation of a buffer control algorithm to accommodate the variable data rate output of the multilevel Huffman encoder. A video CODEC of this type could be used to compress NTSC color television signals where high quality reconstruction is desirable (e.g., Space Station video transmission, transmission direct-to-the-home via direct broadcast satellite systems or cable television distribution to system headends and direct-to-the-home).
Document ID
19920010458
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Bizon, Thomas P. (NASA Lewis Research Center Cleveland, OH, United States)
Whyte, Wayne A., Jr. (NASA Lewis Research Center Cleveland, OH, United States)
Marcopoli, Vincent R. (Case Western Reserve Univ. Cleveland, OH., United States)
Date Acquired
September 6, 2013
Publication Date
January 1, 1992
Subject Category
Communications And Radar
Report/Patent Number
NASA-TM-105616
NAS 1.15:105616
E-6954
Meeting Information
Meeting: Data Compression Conference (DCC 1992)
Location: Snowbird, UT
Country: United States
Start Date: March 24, 1992
End Date: March 26, 1992
Sponsors: IEEE
Accession Number
92N19700
Funding Number(s)
PROJECT: RTOP 144-10-10
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Related Records

There are no records associated with this record.
No Preview Available