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	14e5580246
	
	
	
		
			
			The substreams can have different resampling delays, so an additional level of buffering is needed to synchronize them. Bug-Id: 876
		
			
				
	
	
		
			431 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			431 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * Opus decoder/demuxer common functions
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|  * Copyright (c) 2012 Andrew D'Addesio
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|  * Copyright (c) 2013-2014 Mozilla Corporation
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|  *
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|  * This file is part of Libav.
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|  *
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|  * Libav 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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|  * Libav 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 Libav; 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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| #ifndef AVCODEC_OPUS_H
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| #define AVCODEC_OPUS_H
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| 
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| #include <stdint.h>
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| 
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| #include "libavutil/audio_fifo.h"
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| #include "libavutil/float_dsp.h"
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| #include "libavutil/frame.h"
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| 
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| #include "libavresample/avresample.h"
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| 
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| #include "avcodec.h"
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| #include "get_bits.h"
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| 
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| #define MAX_FRAME_SIZE               1275
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| #define MAX_FRAMES                   48
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| #define MAX_PACKET_DUR               5760
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| 
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| #define CELT_SHORT_BLOCKSIZE         120
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| #define CELT_OVERLAP                 CELT_SHORT_BLOCKSIZE
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| #define CELT_MAX_LOG_BLOCKS          3
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| #define CELT_MAX_FRAME_SIZE          (CELT_SHORT_BLOCKSIZE * (1 << CELT_MAX_LOG_BLOCKS))
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| #define CELT_MAX_BANDS               21
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| #define CELT_VECTORS                 11
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| #define CELT_ALLOC_STEPS             6
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| #define CELT_FINE_OFFSET             21
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| #define CELT_MAX_FINE_BITS           8
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| #define CELT_NORM_SCALE              16384
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| #define CELT_QTHETA_OFFSET           4
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| #define CELT_QTHETA_OFFSET_TWOPHASE  16
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| #define CELT_DEEMPH_COEFF            0.85000610f
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| #define CELT_POSTFILTER_MINPERIOD    15
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| #define CELT_ENERGY_SILENCE          (-28.0f)
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| 
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| #define SILK_HISTORY                 322
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| #define SILK_MAX_LPC                 16
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| 
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| #define ROUND_MULL(a,b,s) (((MUL64(a, b) >> (s - 1)) + 1) >> 1)
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| #define ROUND_MUL16(a,b)  ((MUL16(a, b) + 16384) >> 15)
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| #define opus_ilog(i) (av_log2(i) + !!(i))
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| 
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| #define OPUS_TS_HEADER     0x7FE0        // 0x3ff (11 bits)
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| #define OPUS_TS_MASK       0xFFE0        // top 11 bits
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| 
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| static const uint8_t opus_default_extradata[30] = {
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|     'O', 'p', 'u', 's', 'H', 'e', 'a', 'd',
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|     1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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|     0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
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| };
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| 
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| enum OpusMode {
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|     OPUS_MODE_SILK,
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|     OPUS_MODE_HYBRID,
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|     OPUS_MODE_CELT
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| };
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| 
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| enum OpusBandwidth {
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|     OPUS_BANDWIDTH_NARROWBAND,
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|     OPUS_BANDWIDTH_MEDIUMBAND,
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|     OPUS_BANDWIDTH_WIDEBAND,
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|     OPUS_BANDWIDTH_SUPERWIDEBAND,
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|     OPUS_BANDWIDTH_FULLBAND
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| };
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| 
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| typedef struct RawBitsContext {
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|     const uint8_t *position;
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|     unsigned int bytes;
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|     unsigned int cachelen;
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|     unsigned int cacheval;
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| } RawBitsContext;
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| 
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| typedef struct OpusRangeCoder {
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|     GetBitContext gb;
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|     RawBitsContext rb;
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|     unsigned int range;
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|     unsigned int value;
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|     unsigned int total_read_bits;
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| } OpusRangeCoder;
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| 
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| typedef struct SilkContext SilkContext;
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| 
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| typedef struct CeltContext CeltContext;
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| 
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| typedef struct OpusPacket {
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|     int packet_size;                /** packet size */
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|     int data_size;                  /** size of the useful data -- packet size - padding */
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|     int code;                       /** packet code: specifies the frame layout */
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|     int stereo;                     /** whether this packet is mono or stereo */
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|     int vbr;                        /** vbr flag */
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|     int config;                     /** configuration: tells the audio mode,
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|                                      **                bandwidth, and frame duration */
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|     int frame_count;                /** frame count */
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|     int frame_offset[MAX_FRAMES];   /** frame offsets */
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|     int frame_size[MAX_FRAMES];     /** frame sizes */
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|     int frame_duration;             /** frame duration, in samples @ 48kHz */
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|     enum OpusMode mode;             /** mode */
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|     enum OpusBandwidth bandwidth;   /** bandwidth */
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| } OpusPacket;
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| 
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| typedef struct OpusStreamContext {
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|     AVCodecContext *avctx;
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|     int output_channels;
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| 
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|     OpusRangeCoder rc;
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|     OpusRangeCoder redundancy_rc;
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|     SilkContext *silk;
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|     CeltContext *celt;
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|     AVFloatDSPContext *fdsp;
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| 
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|     float silk_buf[2][960];
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|     float *silk_output[2];
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|     DECLARE_ALIGNED(32, float, celt_buf)[2][960];
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|     float *celt_output[2];
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| 
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|     float redundancy_buf[2][960];
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|     float *redundancy_output[2];
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| 
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|     /* data buffers for the final output data */
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|     float *out[2];
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|     int out_size;
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| 
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|     float *out_dummy;
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|     int    out_dummy_allocated_size;
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| 
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|     AVAudioResampleContext *avr;
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|     AVAudioFifo *celt_delay;
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|     int silk_samplerate;
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|     /* number of samples we still want to get from the resampler */
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|     int delayed_samples;
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| 
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|     OpusPacket packet;
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| 
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|     int redundancy_idx;
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| } OpusStreamContext;
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| 
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| // a mapping between an opus stream and an output channel
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| typedef struct ChannelMap {
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|     int stream_idx;
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|     int channel_idx;
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| 
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|     // when a single decoded channel is mapped to multiple output channels, we
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|     // write to the first output directly and copy from it to the others
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|     // this field is set to 1 for those copied output channels
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|     int copy;
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|     // this is the index of the output channel to copy from
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|     int copy_idx;
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| 
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|     // this channel is silent
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|     int silence;
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| } ChannelMap;
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| 
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| typedef struct OpusContext {
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|     OpusStreamContext *streams;
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| 
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|     /* current output buffers for each streams */
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|     float **out;
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|     int   *out_size;
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|     /* Buffers for synchronizing the streams when they have different
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|      * resampling delays */
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|     AVAudioFifo **sync_buffers;
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|     /* number of decoded samples for each stream */
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|     int         *decoded_samples;
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| 
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|     int             nb_streams;
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|     int      nb_stereo_streams;
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| 
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|     AVFloatDSPContext fdsp;
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|     int16_t gain_i;
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|     float   gain;
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| 
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|     ChannelMap *channel_maps;
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| } OpusContext;
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| 
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| static av_always_inline void opus_rc_normalize(OpusRangeCoder *rc)
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| {
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|     while (rc->range <= 1<<23) {
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|         rc->value = ((rc->value << 8) | (get_bits(&rc->gb, 8) ^ 0xFF)) & ((1u << 31) - 1);
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|         rc->range          <<= 8;
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|         rc->total_read_bits += 8;
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|     }
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| }
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| 
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| static av_always_inline void opus_rc_update(OpusRangeCoder *rc, unsigned int scale,
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|                                           unsigned int low, unsigned int high,
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|                                           unsigned int total)
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| {
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|     rc->value -= scale * (total - high);
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|     rc->range  = low ? scale * (high - low)
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|                       : rc->range - scale * (total - high);
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|     opus_rc_normalize(rc);
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| }
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| 
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| static av_always_inline unsigned int opus_rc_getsymbol(OpusRangeCoder *rc, const uint16_t *cdf)
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| {
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|     unsigned int k, scale, total, symbol, low, high;
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| 
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|     total = *cdf++;
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| 
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|     scale   = rc->range / total;
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|     symbol = rc->value / scale + 1;
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|     symbol = total - FFMIN(symbol, total);
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| 
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|     for (k = 0; cdf[k] <= symbol; k++);
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|     high = cdf[k];
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|     low  = k ? cdf[k-1] : 0;
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| 
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|     opus_rc_update(rc, scale, low, high, total);
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| 
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|     return k;
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| }
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| 
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| static av_always_inline unsigned int opus_rc_p2model(OpusRangeCoder *rc, unsigned int bits)
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| {
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|     unsigned int k, scale;
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|     scale = rc->range >> bits; // in this case, scale = symbol
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| 
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|     if (rc->value >= scale) {
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|         rc->value -= scale;
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|         rc->range -= scale;
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|         k = 0;
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|     } else {
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|         rc->range = scale;
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|         k = 1;
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|     }
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|     opus_rc_normalize(rc);
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|     return k;
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| }
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| 
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| /**
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|  * CELT: estimate bits of entropy that have thus far been consumed for the
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|  *       current CELT frame, to integer and fractional (1/8th bit) precision
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|  */
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| static av_always_inline unsigned int opus_rc_tell(const OpusRangeCoder *rc)
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| {
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|     return rc->total_read_bits - av_log2(rc->range) - 1;
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| }
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| 
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| static av_always_inline unsigned int opus_rc_tell_frac(const OpusRangeCoder *rc)
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| {
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|     unsigned int i, total_bits, rcbuffer, range;
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| 
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|     total_bits = rc->total_read_bits << 3;
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|     rcbuffer   = av_log2(rc->range) + 1;
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|     range      = rc->range >> (rcbuffer-16);
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| 
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|     for (i = 0; i < 3; i++) {
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|         int bit;
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|         range = range * range >> 15;
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|         bit = range >> 16;
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|         rcbuffer = rcbuffer << 1 | bit;
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|         range >>= bit;
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|     }
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| 
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|     return total_bits - rcbuffer;
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| }
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| 
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| /**
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|  * CELT: read 1-25 raw bits at the end of the frame, backwards byte-wise
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|  */
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| static av_always_inline unsigned int opus_getrawbits(OpusRangeCoder *rc, unsigned int count)
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| {
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|     unsigned int value = 0;
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| 
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|     while (rc->rb.bytes && rc->rb.cachelen < count) {
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|         rc->rb.cacheval |= *--rc->rb.position << rc->rb.cachelen;
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|         rc->rb.cachelen += 8;
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|         rc->rb.bytes--;
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|     }
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| 
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|     value = rc->rb.cacheval & ((1<<count)-1);
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|     rc->rb.cacheval    >>= count;
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|     rc->rb.cachelen     -= count;
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|     rc->total_read_bits += count;
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| 
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|     return value;
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| }
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| 
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| /**
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|  * CELT: read a uniform distribution
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|  */
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| static av_always_inline unsigned int opus_rc_unimodel(OpusRangeCoder *rc, unsigned int size)
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| {
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|     unsigned int bits, k, scale, total;
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| 
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|     bits  = opus_ilog(size - 1);
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|     total = (bits > 8) ? ((size - 1) >> (bits - 8)) + 1 : size;
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| 
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|     scale  = rc->range / total;
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|     k      = rc->value / scale + 1;
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|     k      = total - FFMIN(k, total);
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|     opus_rc_update(rc, scale, k, k + 1, total);
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| 
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|     if (bits > 8) {
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|         k = k << (bits - 8) | opus_getrawbits(rc, bits - 8);
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|         return FFMIN(k, size - 1);
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|     } else
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|         return k;
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| }
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| 
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| static av_always_inline int opus_rc_laplace(OpusRangeCoder *rc, unsigned int symbol, int decay)
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| {
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|     /* extends the range coder to model a Laplace distribution */
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|     int value = 0;
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|     unsigned int scale, low = 0, center;
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| 
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|     scale  = rc->range >> 15;
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|     center = rc->value / scale + 1;
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|     center = (1 << 15) - FFMIN(center, 1 << 15);
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| 
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|     if (center >= symbol) {
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|         value++;
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|         low = symbol;
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|         symbol = 1 + ((32768 - 32 - symbol) * (16384-decay) >> 15);
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| 
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|         while (symbol > 1 && center >= low + 2 * symbol) {
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|             value++;
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|             symbol *= 2;
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|             low    += symbol;
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|             symbol  = (((symbol - 2) * decay) >> 15) + 1;
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|         }
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| 
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|         if (symbol <= 1) {
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|             int distance = (center - low) >> 1;
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|             value += distance;
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|             low   += 2 * distance;
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|         }
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| 
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|         if (center < low + symbol)
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|             value *= -1;
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|         else
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|             low += symbol;
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|     }
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| 
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|     opus_rc_update(rc, scale, low, FFMIN(low + symbol, 32768), 32768);
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| 
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|     return value;
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| }
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| 
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| static av_always_inline unsigned int opus_rc_stepmodel(OpusRangeCoder *rc, int k0)
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| {
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|     /* Use a probability of 3 up to itheta=8192 and then use 1 after */
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|     unsigned int k, scale, symbol, total = (k0+1)*3 + k0;
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|     scale  = rc->range / total;
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|     symbol = rc->value / scale + 1;
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|     symbol = total - FFMIN(symbol, total);
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| 
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|     k = (symbol < (k0+1)*3) ? symbol/3 : symbol - (k0+1)*2;
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| 
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|     opus_rc_update(rc, scale, (k <= k0) ? 3*(k+0) : (k-1-k0) + 3*(k0+1),
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|                    (k <= k0) ? 3*(k+1) : (k-0-k0) + 3*(k0+1), total);
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|     return k;
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| }
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| 
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| static av_always_inline unsigned int opus_rc_trimodel(OpusRangeCoder *rc, int qn)
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| {
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|     unsigned int k, scale, symbol, total, low, center;
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| 
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|     total = ((qn>>1) + 1) * ((qn>>1) + 1);
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|     scale   = rc->range / total;
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|     center = rc->value / scale + 1;
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|     center = total - FFMIN(center, total);
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| 
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|     if (center < total >> 1) {
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|         k      = (ff_sqrt(8 * center + 1) - 1) >> 1;
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|         low    = k * (k + 1) >> 1;
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|         symbol = k + 1;
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|     } else {
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|         k      = (2*(qn + 1) - ff_sqrt(8*(total - center - 1) + 1)) >> 1;
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|         low    = total - ((qn + 1 - k) * (qn + 2 - k) >> 1);
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|         symbol = qn + 1 - k;
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|     }
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| 
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|     opus_rc_update(rc, scale, low, low + symbol, total);
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| 
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|     return k;
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| }
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| 
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| int ff_opus_parse_packet(OpusPacket *pkt, const uint8_t *buf, int buf_size,
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|                          int self_delimited);
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| 
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| int ff_opus_parse_extradata(AVCodecContext *avctx, OpusContext *s);
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| 
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| int ff_silk_init(AVCodecContext *avctx, SilkContext **ps, int output_channels);
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| void ff_silk_free(SilkContext **ps);
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| void ff_silk_flush(SilkContext *s);
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| 
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| /**
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|  * Decode the LP layer of one Opus frame (which may correspond to several SILK
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|  * frames).
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|  */
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| int ff_silk_decode_superframe(SilkContext *s, OpusRangeCoder *rc,
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|                               float *output[2],
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|                               enum OpusBandwidth bandwidth, int coded_channels,
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|                               int duration_ms);
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| 
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| int ff_celt_init(AVCodecContext *avctx, CeltContext **s, int output_channels);
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| 
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| void ff_celt_free(CeltContext **s);
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| 
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| void ff_celt_flush(CeltContext *s);
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| 
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| int ff_celt_decode_frame(CeltContext *s, OpusRangeCoder *rc,
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|                          float **output, int coded_channels, int frame_size,
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|                          int startband,  int endband);
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| 
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| extern const float ff_celt_window2[120];
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| 
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| #endif /* AVCODEC_OPUS_H */
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