December 1974 | NTIA Technical Memo OT TM 74 189

Considerations for digital encoding of the NTSC color television signal

Ernest K. Smith

Abstract: This report considers the minimum bit-rate required for trans­mission of NTSC video color standard when used for tele­conferencing. The smallest values are found for fixed cameras. The use of split screen images will increase the required bit­rate by a modest amount. Picture compression techniques considered here are essentially those developed by Bell Labs for use with Picturephone. How­ever, in addition, consideration is given to the possibilities afforded by image transformation (e.g., Hotelling, Fourier, or Hadamard) coupled with psychophysical aspects of vision in order to take account of both frame-to-frame redundancy and intra-frame redundancy. Problems of coding the audio portion separately from the video are also considered briefly. An annex to this report offers material from the CCIR.

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Disclaimer: Certain commercial equipment, components, and software may be identified in this report to specify adequately the technical aspects of the reported results. In no case does such identification imply recommendation or endorsement by the National Telecommunications and Information Administration, nor does it imply that the equipment or software identified is necessarily the best available for the particular application or uses.

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