This is implemented for a vector size of 128-bit. Since the scalar product in the inner loop covers 5 samples or 160 bits, we need a group multipler of 2. To avoid reconfiguring the vector type, the outer loop, which loads multiple input samples sticks to the same multipler. Consequently, the outer loop loads 8 samples per iteration. This is safe since the minimum period of the CELT codec is 15 samples. The same code would also work, albeit needlessly inefficiently with a vector length of 256 bits. A proper implementation will follow instead.
		
			
				
	
	
		
			67 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			67 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * This file is part of FFmpeg.
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|  *
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|  * FFmpeg is free software; you can redistribute it and/or
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|  * modify it under the terms of the GNU Lesser General Public
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|  * License as published by the Free Software Foundation; either
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|  * version 2.1 of the License, or (at your option) any later version.
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|  *
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|  * FFmpeg is distributed in the hope that it will be useful,
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|  * but WITHOUT ANY WARRANTY; without even the implied warranty of
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|  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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|  * Lesser General Public License for more details.
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|  *
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|  * You should have received a copy of the GNU Lesser General Public
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|  * License along with FFmpeg; if not, write to the Free Software
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|  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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|  */
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| 
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| #include "config.h"
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| #include "libavutil/attributes.h"
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| #include "opusdsp.h"
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| 
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| static void postfilter_c(float *data, int period, float *gains, int len)
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| {
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|     const float g0 = gains[0];
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|     const float g1 = gains[1];
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|     const float g2 = gains[2];
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| 
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|     float x4 = data[-period - 2];
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|     float x3 = data[-period - 1];
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|     float x2 = data[-period + 0];
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|     float x1 = data[-period + 1];
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| 
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|     for (int i = 0; i < len; i++) {
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|         float x0 = data[i - period + 2];
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|         data[i] += g0 * x2        +
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|                    g1 * (x1 + x3) +
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|                    g2 * (x0 + x4);
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|         x4 = x3;
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|         x3 = x2;
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|         x2 = x1;
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|         x1 = x0;
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|     }
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| }
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| 
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| static float deemphasis_c(float *y, float *x, float coeff, int len)
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| {
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|     for (int i = 0; i < len; i++)
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|         coeff = y[i] = x[i] + coeff*CELT_EMPH_COEFF;
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| 
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|     return coeff;
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| }
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| 
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| av_cold void ff_opus_dsp_init(OpusDSP *ctx)
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| {
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|     ctx->postfilter = postfilter_c;
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|     ctx->deemphasis = deemphasis_c;
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| 
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| #if ARCH_AARCH64
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|     ff_opus_dsp_init_aarch64(ctx);
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| #elif ARCH_RISCV
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|     ff_opus_dsp_init_riscv(ctx);
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| #elif ARCH_X86
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|     ff_opus_dsp_init_x86(ctx);
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| #endif
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| }
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