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Pseudo-constant bit rate video coding with quantization parameter adjustment

  • US 5,241,383 A
  • Filed: 05/13/1992
  • Issued: 08/31/1993
  • Est. Priority Date: 05/13/1992
  • Status: Expired due to Term
First Claim
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1. A method for coding video frames comprising the steps ofcoding said video frames using a coding circuit including a processor for performing an orthogonal transform to produce transform coefficients and a quantizer for quantizing the transform coefficients to generate code bits at a variable bit rate,storing the code bits in a rate buffer at a variable bit rate and transmitting the code bits out of the rate buffer and into a communication channel at a substantially constant bit rate and,maintaining the contents of said rate buffer in a predetermined range by adjusting quantization parameters utilized by said quantizer to increase or decrease the amount of code bits generated by said coding circuit for a next set of one or more frames, the adjustment of quantization parameters being in response to a deviation between the actual number of code bits generated by the coding circuit for a previous set of one or more frames and an estimate of the number of code bits for said previous set of one or more frames.

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