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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