Patent Number: 8,792,550

Title: Color/gray patch prevention for video coding

Abstract: This disclosure relates to techniques for preventing or reducing the appearance of undesirable color and/or gray patches in decoded video sequences due to generation of out-of-bound quantized transform coefficients during video encoding. Insufficient compression of a video block according to a selected encoding mode and a selected quantization parameter (QP) value may result in the generation and subsequent clipping of out-of-bound quantized transform coefficients for a given video coding standard. The techniques include predicting whether out-of-bound quantized transform coefficients will be generated for a video block, and adjusting at least one of the selected encoding mode and the selected QP value for the video block to prevent the generation of out-of-bound quantized transform coefficients. According to the techniques, the generation of out-of-bound quantized transform coefficients for a video block may be predicted based on difference parameter threshold values, which may be pre-generated and stored in a video encoder.

Inventors: Karuchula; Venkata Naga Poleswara Rao (Hyderabad, IN), Bajaj; Ashish (Hyderabad, IN), Kalanadhabhatla; Surya Manikya Phanindra (Hyderabad, IN), Paladugu; Praneeth (Hyderabad, IN), Bhuvanagiri; Aditya (Hyderabad, IN)

Assignee: QUALCOMM Incorporated

International Classification: H04N 11/04 (20060101)

Expiration Date: 7/29/12018