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	aa2bc61a3e
	
	
	
		
			
			ff_lpc_calc_ref_coeffs returns the order it is given and cannot return in error. Signed-off-by: Derek Buitenhuis <derek.buitenhuis@gmail.com>
		
			
				
	
	
		
			117 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			117 lines
		
	
	
		
			3.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * RFC 3389 comfort noise generator
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|  * Copyright (c) 2012 Martin Storsjo
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|  *
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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 <math.h>
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| 
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| #include "libavutil/common.h"
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| #include "avcodec.h"
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| #include "internal.h"
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| #include "lpc.h"
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| 
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| typedef struct CNGContext {
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|     LPCContext lpc;
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|     int order;
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|     int32_t *samples32;
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|     double *ref_coef;
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| } CNGContext;
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| 
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| static av_cold int cng_encode_close(AVCodecContext *avctx)
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| {
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|     CNGContext *p = avctx->priv_data;
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|     ff_lpc_end(&p->lpc);
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|     av_free(p->samples32);
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|     av_free(p->ref_coef);
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|     return 0;
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| }
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| 
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| static av_cold int cng_encode_init(AVCodecContext *avctx)
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| {
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|     CNGContext *p = avctx->priv_data;
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|     int ret;
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| 
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|     if (avctx->channels != 1) {
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|         av_log(avctx, AV_LOG_ERROR, "Only mono supported\n");
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|         return AVERROR(EINVAL);
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|     }
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| 
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|     avctx->frame_size = 640;
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|     p->order = 10;
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|     if ((ret = ff_lpc_init(&p->lpc, avctx->frame_size, p->order, FF_LPC_TYPE_LEVINSON)) < 0)
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|         return ret;
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|     p->samples32 = av_malloc_array(avctx->frame_size, sizeof(*p->samples32));
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|     p->ref_coef = av_malloc_array(p->order, sizeof(*p->ref_coef));
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|     if (!p->samples32 || !p->ref_coef) {
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|         cng_encode_close(avctx);
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|         return AVERROR(ENOMEM);
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|     }
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| 
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|     return 0;
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| }
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| 
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| static int cng_encode_frame(AVCodecContext *avctx, AVPacket *avpkt,
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|                             const AVFrame *frame, int *got_packet_ptr)
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| {
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|     CNGContext *p = avctx->priv_data;
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|     int ret, i;
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|     double energy = 0;
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|     int qdbov;
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|     int16_t *samples = (int16_t*) frame->data[0];
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| 
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|     if ((ret = ff_alloc_packet2(avctx, avpkt, 1 + p->order, 1 + p->order))) {
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|         av_log(avctx, AV_LOG_ERROR, "Error getting output packet\n");
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|         return ret;
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|     }
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| 
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|     for (i = 0; i < frame->nb_samples; i++) {
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|         p->samples32[i] = samples[i];
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|         energy += samples[i] * samples[i];
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|     }
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|     energy /= frame->nb_samples;
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|     if (energy > 0) {
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|         double dbov = 10 * log10(energy / 1081109975);
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|         qdbov = av_clip_uintp2(-floor(dbov), 7);
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|     } else {
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|         qdbov = 127;
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|     }
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|     ff_lpc_calc_ref_coefs(&p->lpc, p->samples32, p->order, p->ref_coef);
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|     avpkt->data[0] = qdbov;
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|     for (i = 0; i < p->order; i++)
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|         avpkt->data[1 + i] = p->ref_coef[i] * 127 + 127;
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| 
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|     *got_packet_ptr = 1;
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|     av_assert1(avpkt->size == 1 + p->order);
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| 
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|     return 0;
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| }
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| 
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| AVCodec ff_comfortnoise_encoder = {
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|     .name           = "comfortnoise",
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|     .long_name      = NULL_IF_CONFIG_SMALL("RFC 3389 comfort noise generator"),
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|     .type           = AVMEDIA_TYPE_AUDIO,
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|     .id             = AV_CODEC_ID_COMFORT_NOISE,
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|     .priv_data_size = sizeof(CNGContext),
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|     .init           = cng_encode_init,
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|     .encode2        = cng_encode_frame,
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|     .close          = cng_encode_close,
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|     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_S16,
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|                                                      AV_SAMPLE_FMT_NONE },
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| };
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