• Christophe GISQUET's avatar
    rv34: DC-only inverse transform · 3faa303a
    Christophe GISQUET authored
    
    
    When decoding coefficients, detect whether the block is DC-only, and take
    advantage of this knowledge to perform DC-only inverse transform.
    
    This is achieved by:
    - first, changing the 108x4 element modulo_three_table into a 108 element
      table (kind of base4), and accessing each value using mask and shifts.
    - then, checking low bits for 0 (as they represent the presence of higher
      frequency coefficients)
    
    Also provide x86 SIMD code for the DC-only inverse transform.
    
    Signed-off-by: default avatarKostya Shishkov <kostya.shishkov@gmail.com>
    3faa303a