1. 17 4月, 2014 1 次提交
  2. 06 3月, 2012 1 次提交
  3. 02 1月, 2012 1 次提交
    • C
      OMAPDSS: DISPC: Update Fir Coefficients · debd9074
      Chandrabhanu Mahapatra 提交于
      The FIR coefficients present in kernel are being updated to new coefficients
      consisting of 24 coefficient tables, with 12 each for 3 tap and 5 tap scenario,
      which are chosen on the basis of DISPC up/downsampling filters M value. M is
      the inverse of low pass cut off frequency of the sampling filter. For vertical
      scaling 3 tap or 5 tap tables are used based on the clock rate and width of
      the line buffer whereas in OMAP2 3 tap is always used. For horizontal scaling
      however 5 tap tables are always used.
      
      New coefficients and the corresponding logic have been tested on OMAP2, OMAP3
      and OMAP4. Horizontal and vertical scaling worked fine except for some 3 tap
      vs 5 tap issue during vertical upscaling and clock failing issues which is
      acknowledged in the next patch. Vertical upscaling was found to perform better
      under 5 taps. The 24 coefficient tables have been moved to another file
      dispc_coefs.c for proper maintainance.
      
      This code is written based on code written by Lajos Molnar <lajos@ti.com> in
      Android Kernel for scaling. Lajos Molnar <lajos@ti.com> had fine tuned the FIR
      coefficient selection process and reduced outliness and blockiness around
      images when upscaling more than 2 times.
      Signed-off-by: NChandrabhanu Mahapatra <cmahapatra@ti.com>
      Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>
      debd9074