Otherwise doxygen complains about ambiguous filenames when files exist under the same name in different subdirectories. Originally committed as revision 16912 to svn://svn.ffmpeg.org/ffmpeg/trunk
		
			
				
	
	
		
			807 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			807 lines
		
	
	
		
			23 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * The simplest mpeg audio layer 2 encoder
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|  * Copyright (c) 2000, 2001 Fabrice Bellard
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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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| /**
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|  * @file libavcodec/mpegaudio.c
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|  * The simplest mpeg audio layer 2 encoder.
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|  */
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| 
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| #include "avcodec.h"
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| #include "bitstream.h"
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| 
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| #undef  CONFIG_MPEGAUDIO_HP
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| #define CONFIG_MPEGAUDIO_HP 0
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| #include "mpegaudio.h"
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| 
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| /* currently, cannot change these constants (need to modify
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|    quantization stage) */
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| #define MUL(a,b) (((int64_t)(a) * (int64_t)(b)) >> FRAC_BITS)
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| 
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| #define SAMPLES_BUF_SIZE 4096
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| 
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| typedef struct MpegAudioContext {
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|     PutBitContext pb;
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|     int nb_channels;
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|     int freq, bit_rate;
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|     int lsf;           /* 1 if mpeg2 low bitrate selected */
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|     int bitrate_index; /* bit rate */
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|     int freq_index;
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|     int frame_size; /* frame size, in bits, without padding */
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|     int64_t nb_samples; /* total number of samples encoded */
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|     /* padding computation */
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|     int frame_frac, frame_frac_incr, do_padding;
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|     short samples_buf[MPA_MAX_CHANNELS][SAMPLES_BUF_SIZE]; /* buffer for filter */
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|     int samples_offset[MPA_MAX_CHANNELS];       /* offset in samples_buf */
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|     int sb_samples[MPA_MAX_CHANNELS][3][12][SBLIMIT];
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|     unsigned char scale_factors[MPA_MAX_CHANNELS][SBLIMIT][3]; /* scale factors */
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|     /* code to group 3 scale factors */
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|     unsigned char scale_code[MPA_MAX_CHANNELS][SBLIMIT];
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|     int sblimit; /* number of used subbands */
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|     const unsigned char *alloc_table;
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| } MpegAudioContext;
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| 
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| /* define it to use floats in quantization (I don't like floats !) */
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| //#define USE_FLOATS
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| 
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| #include "mpegaudiodata.h"
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| #include "mpegaudiotab.h"
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| 
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| static av_cold int MPA_encode_init(AVCodecContext *avctx)
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| {
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|     MpegAudioContext *s = avctx->priv_data;
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|     int freq = avctx->sample_rate;
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|     int bitrate = avctx->bit_rate;
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|     int channels = avctx->channels;
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|     int i, v, table;
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|     float a;
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| 
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|     if (channels <= 0 || channels > 2){
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|         av_log(avctx, AV_LOG_ERROR, "encoding %d channel(s) is not allowed in mp2\n", channels);
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|         return -1;
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|     }
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|     bitrate = bitrate / 1000;
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|     s->nb_channels = channels;
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|     s->freq = freq;
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|     s->bit_rate = bitrate * 1000;
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|     avctx->frame_size = MPA_FRAME_SIZE;
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| 
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|     /* encoding freq */
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|     s->lsf = 0;
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|     for(i=0;i<3;i++) {
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|         if (ff_mpa_freq_tab[i] == freq)
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|             break;
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|         if ((ff_mpa_freq_tab[i] / 2) == freq) {
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|             s->lsf = 1;
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|             break;
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|         }
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|     }
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|     if (i == 3){
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|         av_log(avctx, AV_LOG_ERROR, "Sampling rate %d is not allowed in mp2\n", freq);
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|         return -1;
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|     }
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|     s->freq_index = i;
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| 
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|     /* encoding bitrate & frequency */
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|     for(i=0;i<15;i++) {
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|         if (ff_mpa_bitrate_tab[s->lsf][1][i] == bitrate)
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|             break;
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|     }
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|     if (i == 15){
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|         av_log(avctx, AV_LOG_ERROR, "bitrate %d is not allowed in mp2\n", bitrate);
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|         return -1;
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|     }
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|     s->bitrate_index = i;
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| 
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|     /* compute total header size & pad bit */
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| 
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|     a = (float)(bitrate * 1000 * MPA_FRAME_SIZE) / (freq * 8.0);
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|     s->frame_size = ((int)a) * 8;
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| 
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|     /* frame fractional size to compute padding */
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|     s->frame_frac = 0;
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|     s->frame_frac_incr = (int)((a - floor(a)) * 65536.0);
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| 
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|     /* select the right allocation table */
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|     table = ff_mpa_l2_select_table(bitrate, s->nb_channels, freq, s->lsf);
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| 
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|     /* number of used subbands */
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|     s->sblimit = ff_mpa_sblimit_table[table];
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|     s->alloc_table = ff_mpa_alloc_tables[table];
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| 
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| #ifdef DEBUG
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|     av_log(avctx, AV_LOG_DEBUG, "%d kb/s, %d Hz, frame_size=%d bits, table=%d, padincr=%x\n",
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|            bitrate, freq, s->frame_size, table, s->frame_frac_incr);
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| #endif
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| 
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|     for(i=0;i<s->nb_channels;i++)
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|         s->samples_offset[i] = 0;
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| 
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|     for(i=0;i<257;i++) {
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|         int v;
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|         v = ff_mpa_enwindow[i];
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| #if WFRAC_BITS != 16
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|         v = (v + (1 << (16 - WFRAC_BITS - 1))) >> (16 - WFRAC_BITS);
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| #endif
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|         filter_bank[i] = v;
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|         if ((i & 63) != 0)
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|             v = -v;
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|         if (i != 0)
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|             filter_bank[512 - i] = v;
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|     }
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| 
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|     for(i=0;i<64;i++) {
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|         v = (int)(pow(2.0, (3 - i) / 3.0) * (1 << 20));
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|         if (v <= 0)
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|             v = 1;
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|         scale_factor_table[i] = v;
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| #ifdef USE_FLOATS
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|         scale_factor_inv_table[i] = pow(2.0, -(3 - i) / 3.0) / (float)(1 << 20);
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| #else
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| #define P 15
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|         scale_factor_shift[i] = 21 - P - (i / 3);
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|         scale_factor_mult[i] = (1 << P) * pow(2.0, (i % 3) / 3.0);
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| #endif
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|     }
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|     for(i=0;i<128;i++) {
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|         v = i - 64;
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|         if (v <= -3)
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|             v = 0;
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|         else if (v < 0)
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|             v = 1;
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|         else if (v == 0)
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|             v = 2;
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|         else if (v < 3)
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|             v = 3;
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|         else
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|             v = 4;
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|         scale_diff_table[i] = v;
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|     }
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| 
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|     for(i=0;i<17;i++) {
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|         v = ff_mpa_quant_bits[i];
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|         if (v < 0)
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|             v = -v;
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|         else
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|             v = v * 3;
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|         total_quant_bits[i] = 12 * v;
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|     }
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| 
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|     avctx->coded_frame= avcodec_alloc_frame();
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|     avctx->coded_frame->key_frame= 1;
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| 
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|     return 0;
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| }
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| 
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| /* 32 point floating point IDCT without 1/sqrt(2) coef zero scaling */
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| static void idct32(int *out, int *tab)
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| {
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|     int i, j;
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|     int *t, *t1, xr;
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|     const int *xp = costab32;
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| 
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|     for(j=31;j>=3;j-=2) tab[j] += tab[j - 2];
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| 
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|     t = tab + 30;
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|     t1 = tab + 2;
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|     do {
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|         t[0] += t[-4];
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|         t[1] += t[1 - 4];
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|         t -= 4;
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|     } while (t != t1);
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| 
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|     t = tab + 28;
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|     t1 = tab + 4;
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|     do {
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|         t[0] += t[-8];
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|         t[1] += t[1-8];
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|         t[2] += t[2-8];
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|         t[3] += t[3-8];
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|         t -= 8;
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|     } while (t != t1);
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| 
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|     t = tab;
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|     t1 = tab + 32;
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|     do {
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|         t[ 3] = -t[ 3];
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|         t[ 6] = -t[ 6];
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| 
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|         t[11] = -t[11];
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|         t[12] = -t[12];
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|         t[13] = -t[13];
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|         t[15] = -t[15];
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|         t += 16;
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|     } while (t != t1);
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| 
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| 
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|     t = tab;
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|     t1 = tab + 8;
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|     do {
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|         int x1, x2, x3, x4;
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| 
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|         x3 = MUL(t[16], FIX(SQRT2*0.5));
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|         x4 = t[0] - x3;
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|         x3 = t[0] + x3;
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| 
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|         x2 = MUL(-(t[24] + t[8]), FIX(SQRT2*0.5));
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|         x1 = MUL((t[8] - x2), xp[0]);
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|         x2 = MUL((t[8] + x2), xp[1]);
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| 
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|         t[ 0] = x3 + x1;
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|         t[ 8] = x4 - x2;
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|         t[16] = x4 + x2;
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|         t[24] = x3 - x1;
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|         t++;
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|     } while (t != t1);
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| 
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|     xp += 2;
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|     t = tab;
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|     t1 = tab + 4;
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|     do {
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|         xr = MUL(t[28],xp[0]);
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|         t[28] = (t[0] - xr);
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|         t[0] = (t[0] + xr);
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| 
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|         xr = MUL(t[4],xp[1]);
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|         t[ 4] = (t[24] - xr);
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|         t[24] = (t[24] + xr);
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| 
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|         xr = MUL(t[20],xp[2]);
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|         t[20] = (t[8] - xr);
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|         t[ 8] = (t[8] + xr);
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| 
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|         xr = MUL(t[12],xp[3]);
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|         t[12] = (t[16] - xr);
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|         t[16] = (t[16] + xr);
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|         t++;
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|     } while (t != t1);
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|     xp += 4;
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| 
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|     for (i = 0; i < 4; i++) {
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|         xr = MUL(tab[30-i*4],xp[0]);
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|         tab[30-i*4] = (tab[i*4] - xr);
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|         tab[   i*4] = (tab[i*4] + xr);
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| 
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|         xr = MUL(tab[ 2+i*4],xp[1]);
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|         tab[ 2+i*4] = (tab[28-i*4] - xr);
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|         tab[28-i*4] = (tab[28-i*4] + xr);
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| 
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|         xr = MUL(tab[31-i*4],xp[0]);
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|         tab[31-i*4] = (tab[1+i*4] - xr);
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|         tab[ 1+i*4] = (tab[1+i*4] + xr);
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| 
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|         xr = MUL(tab[ 3+i*4],xp[1]);
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|         tab[ 3+i*4] = (tab[29-i*4] - xr);
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|         tab[29-i*4] = (tab[29-i*4] + xr);
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| 
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|         xp += 2;
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|     }
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| 
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|     t = tab + 30;
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|     t1 = tab + 1;
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|     do {
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|         xr = MUL(t1[0], *xp);
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|         t1[0] = (t[0] - xr);
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|         t[0] = (t[0] + xr);
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|         t -= 2;
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|         t1 += 2;
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|         xp++;
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|     } while (t >= tab);
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| 
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|     for(i=0;i<32;i++) {
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|         out[i] = tab[bitinv32[i]];
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|     }
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| }
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| 
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| #define WSHIFT (WFRAC_BITS + 15 - FRAC_BITS)
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| 
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| static void filter(MpegAudioContext *s, int ch, short *samples, int incr)
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| {
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|     short *p, *q;
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|     int sum, offset, i, j;
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|     int tmp[64];
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|     int tmp1[32];
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|     int *out;
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| 
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|     //    print_pow1(samples, 1152);
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| 
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|     offset = s->samples_offset[ch];
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|     out = &s->sb_samples[ch][0][0][0];
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|     for(j=0;j<36;j++) {
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|         /* 32 samples at once */
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|         for(i=0;i<32;i++) {
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|             s->samples_buf[ch][offset + (31 - i)] = samples[0];
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|             samples += incr;
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|         }
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| 
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|         /* filter */
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|         p = s->samples_buf[ch] + offset;
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|         q = filter_bank;
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|         /* maxsum = 23169 */
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|         for(i=0;i<64;i++) {
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|             sum = p[0*64] * q[0*64];
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|             sum += p[1*64] * q[1*64];
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|             sum += p[2*64] * q[2*64];
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|             sum += p[3*64] * q[3*64];
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|             sum += p[4*64] * q[4*64];
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|             sum += p[5*64] * q[5*64];
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|             sum += p[6*64] * q[6*64];
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|             sum += p[7*64] * q[7*64];
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|             tmp[i] = sum;
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|             p++;
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|             q++;
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|         }
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|         tmp1[0] = tmp[16] >> WSHIFT;
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|         for( i=1; i<=16; i++ ) tmp1[i] = (tmp[i+16]+tmp[16-i]) >> WSHIFT;
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|         for( i=17; i<=31; i++ ) tmp1[i] = (tmp[i+16]-tmp[80-i]) >> WSHIFT;
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| 
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|         idct32(out, tmp1);
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| 
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|         /* advance of 32 samples */
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|         offset -= 32;
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|         out += 32;
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|         /* handle the wrap around */
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|         if (offset < 0) {
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|             memmove(s->samples_buf[ch] + SAMPLES_BUF_SIZE - (512 - 32),
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|                     s->samples_buf[ch], (512 - 32) * 2);
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|             offset = SAMPLES_BUF_SIZE - 512;
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|         }
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|     }
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|     s->samples_offset[ch] = offset;
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| 
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|     //    print_pow(s->sb_samples, 1152);
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| }
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| 
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| static void compute_scale_factors(unsigned char scale_code[SBLIMIT],
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|                                   unsigned char scale_factors[SBLIMIT][3],
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|                                   int sb_samples[3][12][SBLIMIT],
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|                                   int sblimit)
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| {
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|     int *p, vmax, v, n, i, j, k, code;
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|     int index, d1, d2;
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|     unsigned char *sf = &scale_factors[0][0];
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| 
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|     for(j=0;j<sblimit;j++) {
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|         for(i=0;i<3;i++) {
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|             /* find the max absolute value */
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|             p = &sb_samples[i][0][j];
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|             vmax = abs(*p);
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|             for(k=1;k<12;k++) {
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|                 p += SBLIMIT;
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|                 v = abs(*p);
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|                 if (v > vmax)
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|                     vmax = v;
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|             }
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|             /* compute the scale factor index using log 2 computations */
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|             if (vmax > 1) {
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|                 n = av_log2(vmax);
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|                 /* n is the position of the MSB of vmax. now
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|                    use at most 2 compares to find the index */
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|                 index = (21 - n) * 3 - 3;
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|                 if (index >= 0) {
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|                     while (vmax <= scale_factor_table[index+1])
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|                         index++;
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|                 } else {
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|                     index = 0; /* very unlikely case of overflow */
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|                 }
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|             } else {
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|                 index = 62; /* value 63 is not allowed */
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|             }
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| 
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| #if 0
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|             printf("%2d:%d in=%x %x %d\n",
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|                    j, i, vmax, scale_factor_table[index], index);
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| #endif
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|             /* store the scale factor */
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|             assert(index >=0 && index <= 63);
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|             sf[i] = index;
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|         }
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| 
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|         /* compute the transmission factor : look if the scale factors
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|            are close enough to each other */
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|         d1 = scale_diff_table[sf[0] - sf[1] + 64];
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|         d2 = scale_diff_table[sf[1] - sf[2] + 64];
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| 
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|         /* handle the 25 cases */
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|         switch(d1 * 5 + d2) {
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|         case 0*5+0:
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|         case 0*5+4:
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|         case 3*5+4:
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|         case 4*5+0:
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|         case 4*5+4:
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|             code = 0;
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|             break;
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|         case 0*5+1:
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|         case 0*5+2:
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|         case 4*5+1:
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|         case 4*5+2:
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|             code = 3;
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|             sf[2] = sf[1];
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|             break;
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|         case 0*5+3:
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|         case 4*5+3:
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|             code = 3;
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|             sf[1] = sf[2];
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|             break;
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|         case 1*5+0:
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|         case 1*5+4:
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|         case 2*5+4:
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|             code = 1;
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|             sf[1] = sf[0];
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|             break;
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|         case 1*5+1:
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|         case 1*5+2:
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|         case 2*5+0:
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|         case 2*5+1:
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|         case 2*5+2:
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|             code = 2;
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|             sf[1] = sf[2] = sf[0];
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|             break;
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|         case 2*5+3:
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|         case 3*5+3:
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|             code = 2;
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|             sf[0] = sf[1] = sf[2];
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|             break;
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|         case 3*5+0:
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|         case 3*5+1:
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|         case 3*5+2:
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|             code = 2;
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|             sf[0] = sf[2] = sf[1];
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|             break;
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|         case 1*5+3:
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|             code = 2;
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|             if (sf[0] > sf[2])
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|               sf[0] = sf[2];
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|             sf[1] = sf[2] = sf[0];
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|             break;
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|         default:
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|             assert(0); //cannot happen
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|             code = 0;           /* kill warning */
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|         }
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| 
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| #if 0
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|         printf("%d: %2d %2d %2d %d %d -> %d\n", j,
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|                sf[0], sf[1], sf[2], d1, d2, code);
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| #endif
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|         scale_code[j] = code;
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|         sf += 3;
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|     }
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| }
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| 
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| /* The most important function : psycho acoustic module. In this
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|    encoder there is basically none, so this is the worst you can do,
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|    but also this is the simpler. */
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| static void psycho_acoustic_model(MpegAudioContext *s, short smr[SBLIMIT])
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| {
 | |
|     int i;
 | |
| 
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         smr[i] = (int)(fixed_smr[i] * 10);
 | |
|     }
 | |
| }
 | |
| 
 | |
| 
 | |
| #define SB_NOTALLOCATED  0
 | |
| #define SB_ALLOCATED     1
 | |
| #define SB_NOMORE        2
 | |
| 
 | |
| /* Try to maximize the smr while using a number of bits inferior to
 | |
|    the frame size. I tried to make the code simpler, faster and
 | |
|    smaller than other encoders :-) */
 | |
| static void compute_bit_allocation(MpegAudioContext *s,
 | |
|                                    short smr1[MPA_MAX_CHANNELS][SBLIMIT],
 | |
|                                    unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT],
 | |
|                                    int *padding)
 | |
| {
 | |
|     int i, ch, b, max_smr, max_ch, max_sb, current_frame_size, max_frame_size;
 | |
|     int incr;
 | |
|     short smr[MPA_MAX_CHANNELS][SBLIMIT];
 | |
|     unsigned char subband_status[MPA_MAX_CHANNELS][SBLIMIT];
 | |
|     const unsigned char *alloc;
 | |
| 
 | |
|     memcpy(smr, smr1, s->nb_channels * sizeof(short) * SBLIMIT);
 | |
|     memset(subband_status, SB_NOTALLOCATED, s->nb_channels * SBLIMIT);
 | |
|     memset(bit_alloc, 0, s->nb_channels * SBLIMIT);
 | |
| 
 | |
|     /* compute frame size and padding */
 | |
|     max_frame_size = s->frame_size;
 | |
|     s->frame_frac += s->frame_frac_incr;
 | |
|     if (s->frame_frac >= 65536) {
 | |
|         s->frame_frac -= 65536;
 | |
|         s->do_padding = 1;
 | |
|         max_frame_size += 8;
 | |
|     } else {
 | |
|         s->do_padding = 0;
 | |
|     }
 | |
| 
 | |
|     /* compute the header + bit alloc size */
 | |
|     current_frame_size = 32;
 | |
|     alloc = s->alloc_table;
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         incr = alloc[0];
 | |
|         current_frame_size += incr * s->nb_channels;
 | |
|         alloc += 1 << incr;
 | |
|     }
 | |
|     for(;;) {
 | |
|         /* look for the subband with the largest signal to mask ratio */
 | |
|         max_sb = -1;
 | |
|         max_ch = -1;
 | |
|         max_smr = INT_MIN;
 | |
|         for(ch=0;ch<s->nb_channels;ch++) {
 | |
|             for(i=0;i<s->sblimit;i++) {
 | |
|                 if (smr[ch][i] > max_smr && subband_status[ch][i] != SB_NOMORE) {
 | |
|                     max_smr = smr[ch][i];
 | |
|                     max_sb = i;
 | |
|                     max_ch = ch;
 | |
|                 }
 | |
|             }
 | |
|         }
 | |
| #if 0
 | |
|         printf("current=%d max=%d max_sb=%d alloc=%d\n",
 | |
|                current_frame_size, max_frame_size, max_sb,
 | |
|                bit_alloc[max_sb]);
 | |
| #endif
 | |
|         if (max_sb < 0)
 | |
|             break;
 | |
| 
 | |
|         /* find alloc table entry (XXX: not optimal, should use
 | |
|            pointer table) */
 | |
|         alloc = s->alloc_table;
 | |
|         for(i=0;i<max_sb;i++) {
 | |
|             alloc += 1 << alloc[0];
 | |
|         }
 | |
| 
 | |
|         if (subband_status[max_ch][max_sb] == SB_NOTALLOCATED) {
 | |
|             /* nothing was coded for this band: add the necessary bits */
 | |
|             incr = 2 + nb_scale_factors[s->scale_code[max_ch][max_sb]] * 6;
 | |
|             incr += total_quant_bits[alloc[1]];
 | |
|         } else {
 | |
|             /* increments bit allocation */
 | |
|             b = bit_alloc[max_ch][max_sb];
 | |
|             incr = total_quant_bits[alloc[b + 1]] -
 | |
|                 total_quant_bits[alloc[b]];
 | |
|         }
 | |
| 
 | |
|         if (current_frame_size + incr <= max_frame_size) {
 | |
|             /* can increase size */
 | |
|             b = ++bit_alloc[max_ch][max_sb];
 | |
|             current_frame_size += incr;
 | |
|             /* decrease smr by the resolution we added */
 | |
|             smr[max_ch][max_sb] = smr1[max_ch][max_sb] - quant_snr[alloc[b]];
 | |
|             /* max allocation size reached ? */
 | |
|             if (b == ((1 << alloc[0]) - 1))
 | |
|                 subband_status[max_ch][max_sb] = SB_NOMORE;
 | |
|             else
 | |
|                 subband_status[max_ch][max_sb] = SB_ALLOCATED;
 | |
|         } else {
 | |
|             /* cannot increase the size of this subband */
 | |
|             subband_status[max_ch][max_sb] = SB_NOMORE;
 | |
|         }
 | |
|     }
 | |
|     *padding = max_frame_size - current_frame_size;
 | |
|     assert(*padding >= 0);
 | |
| 
 | |
| #if 0
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         printf("%d ", bit_alloc[i]);
 | |
|     }
 | |
|     printf("\n");
 | |
| #endif
 | |
| }
 | |
| 
 | |
| /*
 | |
|  * Output the mpeg audio layer 2 frame. Note how the code is small
 | |
|  * compared to other encoders :-)
 | |
|  */
 | |
| static void encode_frame(MpegAudioContext *s,
 | |
|                          unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT],
 | |
|                          int padding)
 | |
| {
 | |
|     int i, j, k, l, bit_alloc_bits, b, ch;
 | |
|     unsigned char *sf;
 | |
|     int q[3];
 | |
|     PutBitContext *p = &s->pb;
 | |
| 
 | |
|     /* header */
 | |
| 
 | |
|     put_bits(p, 12, 0xfff);
 | |
|     put_bits(p, 1, 1 - s->lsf); /* 1 = mpeg1 ID, 0 = mpeg2 lsf ID */
 | |
|     put_bits(p, 2, 4-2);  /* layer 2 */
 | |
|     put_bits(p, 1, 1); /* no error protection */
 | |
|     put_bits(p, 4, s->bitrate_index);
 | |
|     put_bits(p, 2, s->freq_index);
 | |
|     put_bits(p, 1, s->do_padding); /* use padding */
 | |
|     put_bits(p, 1, 0);             /* private_bit */
 | |
|     put_bits(p, 2, s->nb_channels == 2 ? MPA_STEREO : MPA_MONO);
 | |
|     put_bits(p, 2, 0); /* mode_ext */
 | |
|     put_bits(p, 1, 0); /* no copyright */
 | |
|     put_bits(p, 1, 1); /* original */
 | |
|     put_bits(p, 2, 0); /* no emphasis */
 | |
| 
 | |
|     /* bit allocation */
 | |
|     j = 0;
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         bit_alloc_bits = s->alloc_table[j];
 | |
|         for(ch=0;ch<s->nb_channels;ch++) {
 | |
|             put_bits(p, bit_alloc_bits, bit_alloc[ch][i]);
 | |
|         }
 | |
|         j += 1 << bit_alloc_bits;
 | |
|     }
 | |
| 
 | |
|     /* scale codes */
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         for(ch=0;ch<s->nb_channels;ch++) {
 | |
|             if (bit_alloc[ch][i])
 | |
|                 put_bits(p, 2, s->scale_code[ch][i]);
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     /* scale factors */
 | |
|     for(i=0;i<s->sblimit;i++) {
 | |
|         for(ch=0;ch<s->nb_channels;ch++) {
 | |
|             if (bit_alloc[ch][i]) {
 | |
|                 sf = &s->scale_factors[ch][i][0];
 | |
|                 switch(s->scale_code[ch][i]) {
 | |
|                 case 0:
 | |
|                     put_bits(p, 6, sf[0]);
 | |
|                     put_bits(p, 6, sf[1]);
 | |
|                     put_bits(p, 6, sf[2]);
 | |
|                     break;
 | |
|                 case 3:
 | |
|                 case 1:
 | |
|                     put_bits(p, 6, sf[0]);
 | |
|                     put_bits(p, 6, sf[2]);
 | |
|                     break;
 | |
|                 case 2:
 | |
|                     put_bits(p, 6, sf[0]);
 | |
|                     break;
 | |
|                 }
 | |
|             }
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     /* quantization & write sub band samples */
 | |
| 
 | |
|     for(k=0;k<3;k++) {
 | |
|         for(l=0;l<12;l+=3) {
 | |
|             j = 0;
 | |
|             for(i=0;i<s->sblimit;i++) {
 | |
|                 bit_alloc_bits = s->alloc_table[j];
 | |
|                 for(ch=0;ch<s->nb_channels;ch++) {
 | |
|                     b = bit_alloc[ch][i];
 | |
|                     if (b) {
 | |
|                         int qindex, steps, m, sample, bits;
 | |
|                         /* we encode 3 sub band samples of the same sub band at a time */
 | |
|                         qindex = s->alloc_table[j+b];
 | |
|                         steps = ff_mpa_quant_steps[qindex];
 | |
|                         for(m=0;m<3;m++) {
 | |
|                             sample = s->sb_samples[ch][k][l + m][i];
 | |
|                             /* divide by scale factor */
 | |
| #ifdef USE_FLOATS
 | |
|                             {
 | |
|                                 float a;
 | |
|                                 a = (float)sample * scale_factor_inv_table[s->scale_factors[ch][i][k]];
 | |
|                                 q[m] = (int)((a + 1.0) * steps * 0.5);
 | |
|                             }
 | |
| #else
 | |
|                             {
 | |
|                                 int q1, e, shift, mult;
 | |
|                                 e = s->scale_factors[ch][i][k];
 | |
|                                 shift = scale_factor_shift[e];
 | |
|                                 mult = scale_factor_mult[e];
 | |
| 
 | |
|                                 /* normalize to P bits */
 | |
|                                 if (shift < 0)
 | |
|                                     q1 = sample << (-shift);
 | |
|                                 else
 | |
|                                     q1 = sample >> shift;
 | |
|                                 q1 = (q1 * mult) >> P;
 | |
|                                 q[m] = ((q1 + (1 << P)) * steps) >> (P + 1);
 | |
|                             }
 | |
| #endif
 | |
|                             if (q[m] >= steps)
 | |
|                                 q[m] = steps - 1;
 | |
|                             assert(q[m] >= 0 && q[m] < steps);
 | |
|                         }
 | |
|                         bits = ff_mpa_quant_bits[qindex];
 | |
|                         if (bits < 0) {
 | |
|                             /* group the 3 values to save bits */
 | |
|                             put_bits(p, -bits,
 | |
|                                      q[0] + steps * (q[1] + steps * q[2]));
 | |
| #if 0
 | |
|                             printf("%d: gr1 %d\n",
 | |
|                                    i, q[0] + steps * (q[1] + steps * q[2]));
 | |
| #endif
 | |
|                         } else {
 | |
| #if 0
 | |
|                             printf("%d: gr3 %d %d %d\n",
 | |
|                                    i, q[0], q[1], q[2]);
 | |
| #endif
 | |
|                             put_bits(p, bits, q[0]);
 | |
|                             put_bits(p, bits, q[1]);
 | |
|                             put_bits(p, bits, q[2]);
 | |
|                         }
 | |
|                     }
 | |
|                 }
 | |
|                 /* next subband in alloc table */
 | |
|                 j += 1 << bit_alloc_bits;
 | |
|             }
 | |
|         }
 | |
|     }
 | |
| 
 | |
|     /* padding */
 | |
|     for(i=0;i<padding;i++)
 | |
|         put_bits(p, 1, 0);
 | |
| 
 | |
|     /* flush */
 | |
|     flush_put_bits(p);
 | |
| }
 | |
| 
 | |
| static int MPA_encode_frame(AVCodecContext *avctx,
 | |
|                             unsigned char *frame, int buf_size, void *data)
 | |
| {
 | |
|     MpegAudioContext *s = avctx->priv_data;
 | |
|     short *samples = data;
 | |
|     short smr[MPA_MAX_CHANNELS][SBLIMIT];
 | |
|     unsigned char bit_alloc[MPA_MAX_CHANNELS][SBLIMIT];
 | |
|     int padding, i;
 | |
| 
 | |
|     for(i=0;i<s->nb_channels;i++) {
 | |
|         filter(s, i, samples + i, s->nb_channels);
 | |
|     }
 | |
| 
 | |
|     for(i=0;i<s->nb_channels;i++) {
 | |
|         compute_scale_factors(s->scale_code[i], s->scale_factors[i],
 | |
|                               s->sb_samples[i], s->sblimit);
 | |
|     }
 | |
|     for(i=0;i<s->nb_channels;i++) {
 | |
|         psycho_acoustic_model(s, smr[i]);
 | |
|     }
 | |
|     compute_bit_allocation(s, smr, bit_alloc, &padding);
 | |
| 
 | |
|     init_put_bits(&s->pb, frame, MPA_MAX_CODED_FRAME_SIZE);
 | |
| 
 | |
|     encode_frame(s, bit_alloc, padding);
 | |
| 
 | |
|     s->nb_samples += MPA_FRAME_SIZE;
 | |
|     return pbBufPtr(&s->pb) - s->pb.buf;
 | |
| }
 | |
| 
 | |
| static av_cold int MPA_encode_close(AVCodecContext *avctx)
 | |
| {
 | |
|     av_freep(&avctx->coded_frame);
 | |
|     return 0;
 | |
| }
 | |
| 
 | |
| AVCodec mp2_encoder = {
 | |
|     "mp2",
 | |
|     CODEC_TYPE_AUDIO,
 | |
|     CODEC_ID_MP2,
 | |
|     sizeof(MpegAudioContext),
 | |
|     MPA_encode_init,
 | |
|     MPA_encode_frame,
 | |
|     MPA_encode_close,
 | |
|     NULL,
 | |
|     .sample_fmts = (enum SampleFormat[]){SAMPLE_FMT_S16,SAMPLE_FMT_NONE},
 | |
|     .long_name = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),
 | |
| };
 | |
| 
 | |
| #undef FIX
 |