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Merge pull request #314 from nfedera/ycbcr_to_rgb_fix_and_sse2_speedup

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codec: fixed and accelerated RemoteFX ycbcr-to-rgb decoder
This commit is contained in:
Marc-André Moreau 2011-12-27 08:35:25 -08:00
commit 2cd52d34cf
2 changed files with 48 additions and 41 deletions
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20
libfreerdp-codec/rfx_decode.c
View File

@ -98,19 +98,17 @@ void rfx_decode_ycbcr_to_rgb(sint16* y_r_buf, sint16* cb_g_buf, sint16* cr_b_buf
*/
for (i = 0; i < 4096; i++)
{
y = (y_r_buf[i] >> 5) + 128;
y = y_r_buf[i] + 4096; // 128<<5 = 4096 so that we can >> 5 over the sum
cb = cb_g_buf[i];
cr = cr_b_buf[i];
/* 1.403 >> 5 = 0.000010110011100(b) */
r = y + ((cr >> 5) + (cr >> 7) + (cr >> 8) + (cr >> 11) + (cr >> 12) + (cr >> 13));
y_r_buf[i] = MINMAX(r, 0, 255);
/* 0.344 >> 5 = 0.000000101100000(b), 0.714 >> 5 = 0.000001011011011(b) */
g = y - ((cb >> 7) + (cb >> 9) + (cb >> 10)) -
((cr >> 6) + (cr >> 8) + (cr >> 9) + (cr >> 11) + (cr >> 12) + (cr >> 13));
cb_g_buf[i] = MINMAX(g, 0, 255);
/* 1.77 >> 5 = 0.000011100010100(b) */
b = y + ((cb >> 5) + (cb >> 6) + (cb >> 7) + (cb >> 11) + (cb >> 13));
cr_b_buf[i] = MINMAX(b, 0, 255);
r = y + cr*1.403f;
g = y - cb*0.344f - cr*0.714f;
b = y + cb*1.770f;
y_r_buf[i] = MINMAX(r>>5, 0, 255);
cb_g_buf[i] = MINMAX(g>>5, 0, 255);
cr_b_buf[i] = MINMAX(b>>5, 0, 255);
}
}

69
libfreerdp-codec/rfx_sse2.c
View File

@ -3,6 +3,7 @@
* RemoteFX Codec Library - SSE2 Optimizations
*
* Copyright 2011 Stephen Erisman
* Copyright 2011 Norbert Federa <nfedera@thinstuff.com>
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
@ -64,6 +65,12 @@ static void rfx_decode_ycbcr_to_rgb_sse2(sint16* y_r_buffer, sint16* cb_g_buffer
int i;
__m128i r_cr = _mm_set1_epi16(22986); // 1.403 << 14
__m128i g_cb = _mm_set1_epi16(-5636); // -0.344 << 14
__m128i g_cr = _mm_set1_epi16(-11698); // -0.714 << 14
__m128i b_cb = _mm_set1_epi16(28999); // 1.770 << 14
__m128i c4096 = _mm_set1_epi16(4096);
for (i = 0; i < (4096 * sizeof(sint16) / sizeof(__m128i)); i += (CACHE_LINE_BYTES / sizeof(__m128i)))
{
_mm_prefetch((char*)(&y_r_buf[i]), _MM_HINT_NTA);
@ -72,49 +79,51 @@ static void rfx_decode_ycbcr_to_rgb_sse2(sint16* y_r_buffer, sint16* cb_g_buffer
}
for (i = 0; i < (4096 * sizeof(sint16) / sizeof(__m128i)); i++)
{
/* y = (y_r_buf[i] >> 5) + 128; */
y = _mm_load_si128(&y_r_buf[i]);
y = _mm_add_epi16(_mm_srai_epi16(y, 5), _mm_set1_epi16(128));
/*
In order to use SSE2 signed 16-bit integer multiplication we need to convert
the floating point factors to signed int without loosing information.
The result of this multiplication is 32 bit and we have two SSE instructions
that return either the hi or lo word.
Thus we will multiply the factors by the highest possible 2^n, take the
upper 16 bits of the signed 32-bit result (_mm_mulhi_epi16) and correct this
result by multiplying it by 2^(16-n).
For the given factors in the conversion matrix the best possible n is 14.
Example for calculating r:
r = (y>>5) + 128 + (cr*1.403)>>5 // our base formula
r = (y>>5) + 128 + (HIWORD(cr*(1.403<<14)<<2))>>5 // see above
r = (y+4096)>>5 + (HIWORD(cr*22986)<<2)>>5 // simplification
r = ((y+4096)>>2 + HIWORD(cr*22986)) >> 3
*/
/* y = (y_r_buf[i] + 4096) >> 2 */
y = _mm_load_si128(&y_r_buf[i]);
y = _mm_add_epi16(y, c4096);
y = _mm_srai_epi16(y, 2);
/* cb = cb_g_buf[i]; */
cb = _mm_load_si128(&cb_g_buf[i]);
/* cr = cr_b_buf[i]; */
cr = _mm_load_si128(&cr_b_buf[i]);
/* r = y + ((cr >> 5) + (cr >> 7) + (cr >> 8) + (cr >> 11) + (cr >> 12) + (cr >> 13)); */
/* (y + HIWORD(cr*22986)) >> 3 */
r = _mm_add_epi16(y, _mm_mulhi_epi16(cr, r_cr));
r = _mm_srai_epi16(r, 3);
/* y_r_buf[i] = MINMAX(r, 0, 255); */
r = _mm_add_epi16(y, _mm_srai_epi16(cr, 5));
r = _mm_add_epi16(r, _mm_srai_epi16(cr, 7));
r = _mm_add_epi16(r, _mm_srai_epi16(cr, 8));
r = _mm_add_epi16(r, _mm_srai_epi16(cr, 11));
r = _mm_add_epi16(r, _mm_srai_epi16(cr, 12));
r = _mm_add_epi16(r, _mm_srai_epi16(cr, 13));
_mm_between_epi16(r, zero, max);
_mm_store_si128(&y_r_buf[i], r);
/* cb = cb_g_buf[i]; */
cb = _mm_load_si128(&cb_g_buf[i]);
/* g = y - ((cb >> 7) + (cb >> 9) + (cb >> 10)) -
((cr >> 6) + (cr >> 8) + (cr >> 9) + (cr >> 11) + (cr >> 12) + (cr >> 13)); */
/* (y + HIWORD(cb*-5636) + HIWORD(cr*-11698)) >> 3 */
g = _mm_add_epi16(y, _mm_mulhi_epi16(cb, g_cb));
g = _mm_add_epi16(g, _mm_mulhi_epi16(cr, g_cr));
g = _mm_srai_epi16(g, 3);
/* cb_g_buf[i] = MINMAX(g, 0, 255); */
g = _mm_sub_epi16(y, _mm_srai_epi16(cb, 7));
g = _mm_sub_epi16(g, _mm_srai_epi16(cb, 9));
g = _mm_sub_epi16(g, _mm_srai_epi16(cb, 10));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 6));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 8));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 9));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 11));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 12));
g = _mm_sub_epi16(g, _mm_srai_epi16(cr, 13));
_mm_between_epi16(g, zero, max);
_mm_store_si128(&cb_g_buf[i], g);
/* b = y + ((cb >> 5) + (cb >> 6) + (cb >> 7) + (cb >> 11) + (cb >> 13)); */
/* (y + HIWORD(cb*28999)) >> 3 */
b = _mm_add_epi16(y, _mm_mulhi_epi16(cb, b_cb));
b = _mm_srai_epi16(b, 3);
/* cr_b_buf[i] = MINMAX(b, 0, 255); */
b = _mm_add_epi16(y, _mm_srai_epi16(cb, 5));
b = _mm_add_epi16(b, _mm_srai_epi16(cb, 6));
b = _mm_add_epi16(b, _mm_srai_epi16(cb, 7));
b = _mm_add_epi16(b, _mm_srai_epi16(cb, 11));
b = _mm_add_epi16(b, _mm_srai_epi16(cb, 13));
_mm_between_epi16(b, zero, max);
_mm_store_si128(&cr_b_buf[i], b);
}