1/* 2 * NellyMoser audio decoder 3 * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5, 4 * 539459aeb7d425140b62a3ec7dbf6dc8e408a306, and 5 * 520e17cd55896441042b14df2566a6eb610ed444 6 * Copyright (c) 2007 Loic Minier <lool at dooz.org> 7 * Benjamin Larsson 8 * 9 * Permission is hereby granted, free of charge, to any person obtaining a 10 * copy of this software and associated documentation files (the "Software"), 11 * to deal in the Software without restriction, including without limitation 12 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 13 * and/or sell copies of the Software, and to permit persons to whom the 14 * Software is furnished to do so, subject to the following conditions: 15 * 16 * The above copyright notice and this permission notice shall be included in 17 * all copies or substantial portions of the Software. 18 * 19 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 20 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 21 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 22 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 23 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 25 * DEALINGS IN THE SOFTWARE. 26 */ 27 28/** 29 * @file 30 * The 3 alphanumeric copyright notices are md5summed they are from the original 31 * implementors. The original code is available from http://code.google.com/p/nelly2pcm/ 32 */ 33 34#include "nellymoser.h" 35#include "libavutil/lfg.h" 36#include "libavutil/random_seed.h" 37#include "avcodec.h" 38#include "dsputil.h" 39#include "fft.h" 40 41#define ALT_BITSTREAM_READER_LE 42#include "get_bits.h" 43 44 45typedef struct NellyMoserDecodeContext { 46 AVCodecContext* avctx; 47 DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES]; 48 float state[128]; 49 AVLFG random_state; 50 GetBitContext gb; 51 int add_bias; 52 float scale_bias; 53 DSPContext dsp; 54 FFTContext imdct_ctx; 55 DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2]; 56} NellyMoserDecodeContext; 57 58static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in) 59{ 60 int bot, top; 61 62 bot = 0; 63 top = NELLY_BUF_LEN-1; 64 65 while (bot < NELLY_BUF_LEN) { 66 audio[bot] = a_in [bot]*ff_sine_128[bot] 67 +state[bot]*ff_sine_128[top] + s->add_bias; 68 69 bot++; 70 top--; 71 } 72 memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN); 73} 74 75static void nelly_decode_block(NellyMoserDecodeContext *s, 76 const unsigned char block[NELLY_BLOCK_LEN], 77 float audio[NELLY_SAMPLES]) 78{ 79 int i,j; 80 float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN]; 81 float *aptr, *bptr, *pptr, val, pval; 82 int bits[NELLY_BUF_LEN]; 83 unsigned char v; 84 85 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8); 86 87 bptr = buf; 88 pptr = pows; 89 val = ff_nelly_init_table[get_bits(&s->gb, 6)]; 90 for (i=0 ; i<NELLY_BANDS ; i++) { 91 if (i > 0) 92 val += ff_nelly_delta_table[get_bits(&s->gb, 5)]; 93 pval = -pow(2, val/2048) * s->scale_bias; 94 for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) { 95 *bptr++ = val; 96 *pptr++ = pval; 97 } 98 99 } 100 101 ff_nelly_get_sample_bits(buf, bits); 102 103 for (i = 0; i < 2; i++) { 104 aptr = audio + i * NELLY_BUF_LEN; 105 106 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8); 107 skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS); 108 109 for (j = 0; j < NELLY_FILL_LEN; j++) { 110 if (bits[j] <= 0) { 111 aptr[j] = M_SQRT1_2*pows[j]; 112 if (av_lfg_get(&s->random_state) & 1) 113 aptr[j] *= -1.0; 114 } else { 115 v = get_bits(&s->gb, bits[j]); 116 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j]; 117 } 118 } 119 memset(&aptr[NELLY_FILL_LEN], 0, 120 (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float)); 121 122 ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr); 123 /* XXX: overlapping and windowing should be part of a more 124 generic imdct function */ 125 overlap_and_window(s, s->state, aptr, s->imdct_out); 126 } 127} 128 129static av_cold int decode_init(AVCodecContext * avctx) { 130 NellyMoserDecodeContext *s = avctx->priv_data; 131 132 s->avctx = avctx; 133 av_lfg_init(&s->random_state, 0); 134 ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0); 135 136 dsputil_init(&s->dsp, avctx); 137 138 if(s->dsp.float_to_int16 == ff_float_to_int16_c) { 139 s->add_bias = 385; 140 s->scale_bias = 1.0/(8*32768); 141 } else { 142 s->add_bias = 0; 143 s->scale_bias = 1.0/(1*8); 144 } 145 146 /* Generate overlap window */ 147 if (!ff_sine_128[127]) 148 ff_init_ff_sine_windows(7); 149 150 avctx->sample_fmt = SAMPLE_FMT_S16; 151 avctx->channel_layout = CH_LAYOUT_MONO; 152 return 0; 153} 154 155static int decode_tag(AVCodecContext * avctx, 156 void *data, int *data_size, 157 AVPacket *avpkt) { 158 const uint8_t *buf = avpkt->data; 159 int buf_size = avpkt->size; 160 NellyMoserDecodeContext *s = avctx->priv_data; 161 int blocks, i; 162 int16_t* samples; 163 *data_size = 0; 164 samples = (int16_t*)data; 165 166 if (buf_size < avctx->block_align) 167 return buf_size; 168 169 switch (buf_size) { 170 case 64: // 8000Hz 171 blocks = 1; break; 172 case 128: // 11025Hz 173 blocks = 2; break; 174 case 192: // 16000Hz 175 blocks = 3; break; 176 case 256: // 22050Hz 177 blocks = 4; break; 178 case 512: // 44100Hz 179 blocks = 8; break; 180 default: 181 av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size); 182 return buf_size; 183 } 184 185 for (i=0 ; i<blocks ; i++) { 186 nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf); 187 s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES); 188 *data_size += NELLY_SAMPLES*sizeof(int16_t); 189 } 190 191 return buf_size; 192} 193 194static av_cold int decode_end(AVCodecContext * avctx) { 195 NellyMoserDecodeContext *s = avctx->priv_data; 196 197 ff_mdct_end(&s->imdct_ctx); 198 return 0; 199} 200 201AVCodec nellymoser_decoder = { 202 "nellymoser", 203 AVMEDIA_TYPE_AUDIO, 204 CODEC_ID_NELLYMOSER, 205 sizeof(NellyMoserDecodeContext), 206 decode_init, 207 NULL, 208 decode_end, 209 decode_tag, 210 .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"), 211}; 212 213