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Extend to 256 Q steps.

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This commit extends the number of Q steps to 256 from 128.
The q_trans[] array has been altered to distribute available Q index values
(using the current 64 steps available as input parameters) evenly across the
available range. This is coupled with the fact that each Q step where possible
now equates to a fixed % change in the quantizer. This may want refinement
later especially in terms of the granularity at the high quality end but is a
reasonable starting point.

Change-Id: I2aaa6874fa10ce05c958dd182947ce39f6f1eecb
This commit is contained in:
Paul Wilkins 2011-12-16 10:23:01 +00:00
parent ec670bc558
commit df4e79f7f7
3 changed files with 10 additions and 9 deletions
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6
vp8/common/onyxc_int.h
View File

@ -33,13 +33,13 @@ void vp8_initialize_common(void);
#define MINQ 0
/*#if CONFIG_EXTEND_QRANGE
#if CONFIG_EXTEND_QRANGE
#define MAXQ 255
#define QINDEX_BITS 8
#else*/
#else
#define MAXQ 127
#define QINDEX_BITS 7
//#endif
#endif
#define QINDEX_RANGE (MAXQ + 1)

7
vp8/common/quant_common.c
View File

@ -89,7 +89,8 @@ void vp8_init_quant_tables()
{
ac_qlookup[i] = current_val;
//current_val = (int)((double)current_val * 1.045);
current_val = (int)((double)current_val * 1.04);
//current_val = (int)((double)current_val * 1.04);
current_val = (int)((double)current_val * 1.018);
if ( current_val == last_val )
current_val++;
last_val = current_val;
@ -99,8 +100,8 @@ void vp8_init_quant_tables()
dc_qlookup[i] = (0.000000305 * ac_val * ac_val * ac_val) +
(-0.00065 * ac_val * ac_val) +
(0.9 * ac_val) + 0.5;
if ( dc_qlookup[i] > dc_max )
dc_qlookup[i] = dc_max;
//if ( dc_qlookup[i] > dc_max )
// dc_qlookup[i] = dc_max;
if ( dc_qlookup[i] < ACDC_MIN )
dc_qlookup[i] = ACDC_MIN;
}

6
vp8/encoder/onyx_if.c
View File

@ -1857,7 +1857,7 @@ void vp8_alloc_compressor_data(VP8_COMP *cpi)
//
// Table that converts 0-63 Q range values passed in outside to the Qindex
// range used internally.
/*#if CONFIG_EXTEND_QRANGE
#if CONFIG_EXTEND_QRANGE
static const int q_trans[] =
{
0, 4, 8, 12, 16, 20, 24, 28,
@ -1869,7 +1869,7 @@ static const int q_trans[] =
192, 196, 200, 204, 208, 212, 216, 220,
224, 228, 232, 236, 240, 244, 249, 255,
};
#else*/
#else
static const int q_trans[] =
{
0, 1, 2, 3, 4, 5, 7, 8,
@ -1881,7 +1881,7 @@ static const int q_trans[] =
82, 85, 88, 91, 94, 97, 100, 103,
106, 109, 112, 115, 118, 121, 124, 127,
};
//#endif
#endif
int vp8_reverse_trans(int x)
{