Libav
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00001 /* 00002 * NellyMoser audio decoder 00003 * Copyright (c) 2007 a840bda5870ba11f19698ff6eb9581dfb0f95fa5, 00004 * 539459aeb7d425140b62a3ec7dbf6dc8e408a306, and 00005 * 520e17cd55896441042b14df2566a6eb610ed444 00006 * Copyright (c) 2007 Loic Minier <lool at dooz.org> 00007 * Benjamin Larsson 00008 * 00009 * Permission is hereby granted, free of charge, to any person obtaining a 00010 * copy of this software and associated documentation files (the "Software"), 00011 * to deal in the Software without restriction, including without limitation 00012 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 00013 * and/or sell copies of the Software, and to permit persons to whom the 00014 * Software is furnished to do so, subject to the following conditions: 00015 * 00016 * The above copyright notice and this permission notice shall be included in 00017 * all copies or substantial portions of the Software. 00018 * 00019 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 00020 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 00021 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 00022 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 00023 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 00024 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER 00025 * DEALINGS IN THE SOFTWARE. 00026 */ 00027 00034 #include "nellymoser.h" 00035 #include "libavutil/lfg.h" 00036 #include "libavutil/random_seed.h" 00037 #include "avcodec.h" 00038 #include "dsputil.h" 00039 #include "fft.h" 00040 00041 #define ALT_BITSTREAM_READER_LE 00042 #include "get_bits.h" 00043 00044 00045 typedef struct NellyMoserDecodeContext { 00046 AVCodecContext* avctx; 00047 DECLARE_ALIGNED(16, float,float_buf)[NELLY_SAMPLES]; 00048 float state[128]; 00049 AVLFG random_state; 00050 GetBitContext gb; 00051 int add_bias; 00052 float scale_bias; 00053 DSPContext dsp; 00054 FFTContext imdct_ctx; 00055 DECLARE_ALIGNED(16, float,imdct_out)[NELLY_BUF_LEN * 2]; 00056 } NellyMoserDecodeContext; 00057 00058 static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in) 00059 { 00060 int bot, top; 00061 00062 bot = 0; 00063 top = NELLY_BUF_LEN-1; 00064 00065 while (bot < NELLY_BUF_LEN) { 00066 audio[bot] = a_in [bot]*ff_sine_128[bot] 00067 +state[bot]*ff_sine_128[top] + s->add_bias; 00068 00069 bot++; 00070 top--; 00071 } 00072 memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN); 00073 } 00074 00075 static void nelly_decode_block(NellyMoserDecodeContext *s, 00076 const unsigned char block[NELLY_BLOCK_LEN], 00077 float audio[NELLY_SAMPLES]) 00078 { 00079 int i,j; 00080 float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN]; 00081 float *aptr, *bptr, *pptr, val, pval; 00082 int bits[NELLY_BUF_LEN]; 00083 unsigned char v; 00084 00085 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8); 00086 00087 bptr = buf; 00088 pptr = pows; 00089 val = ff_nelly_init_table[get_bits(&s->gb, 6)]; 00090 for (i=0 ; i<NELLY_BANDS ; i++) { 00091 if (i > 0) 00092 val += ff_nelly_delta_table[get_bits(&s->gb, 5)]; 00093 pval = -pow(2, val/2048) * s->scale_bias; 00094 for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) { 00095 *bptr++ = val; 00096 *pptr++ = pval; 00097 } 00098 00099 } 00100 00101 ff_nelly_get_sample_bits(buf, bits); 00102 00103 for (i = 0; i < 2; i++) { 00104 aptr = audio + i * NELLY_BUF_LEN; 00105 00106 init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8); 00107 skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS); 00108 00109 for (j = 0; j < NELLY_FILL_LEN; j++) { 00110 if (bits[j] <= 0) { 00111 aptr[j] = M_SQRT1_2*pows[j]; 00112 if (av_lfg_get(&s->random_state) & 1) 00113 aptr[j] *= -1.0; 00114 } else { 00115 v = get_bits(&s->gb, bits[j]); 00116 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j]; 00117 } 00118 } 00119 memset(&aptr[NELLY_FILL_LEN], 0, 00120 (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float)); 00121 00122 ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr); 00123 /* XXX: overlapping and windowing should be part of a more 00124 generic imdct function */ 00125 overlap_and_window(s, s->state, aptr, s->imdct_out); 00126 } 00127 } 00128 00129 static av_cold int decode_init(AVCodecContext * avctx) { 00130 NellyMoserDecodeContext *s = avctx->priv_data; 00131 00132 s->avctx = avctx; 00133 av_lfg_init(&s->random_state, 0); 00134 ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0); 00135 00136 dsputil_init(&s->dsp, avctx); 00137 00138 if(s->dsp.float_to_int16 == ff_float_to_int16_c) { 00139 s->add_bias = 385; 00140 s->scale_bias = 1.0/(8*32768); 00141 } else { 00142 s->add_bias = 0; 00143 s->scale_bias = 1.0/(1*8); 00144 } 00145 00146 /* Generate overlap window */ 00147 if (!ff_sine_128[127]) 00148 ff_init_ff_sine_windows(7); 00149 00150 avctx->sample_fmt = SAMPLE_FMT_S16; 00151 avctx->channel_layout = CH_LAYOUT_MONO; 00152 return 0; 00153 } 00154 00155 static int decode_tag(AVCodecContext * avctx, 00156 void *data, int *data_size, 00157 AVPacket *avpkt) { 00158 const uint8_t *buf = avpkt->data; 00159 int buf_size = avpkt->size; 00160 NellyMoserDecodeContext *s = avctx->priv_data; 00161 int blocks, i; 00162 int16_t* samples; 00163 *data_size = 0; 00164 samples = (int16_t*)data; 00165 00166 if (buf_size < avctx->block_align) 00167 return buf_size; 00168 00169 switch (buf_size) { 00170 case 64: // 8000Hz 00171 blocks = 1; break; 00172 case 128: // 11025Hz 00173 blocks = 2; break; 00174 case 192: // 16000Hz 00175 blocks = 3; break; 00176 case 256: // 22050Hz 00177 blocks = 4; break; 00178 case 512: // 44100Hz 00179 blocks = 8; break; 00180 default: 00181 av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size); 00182 return buf_size; 00183 } 00184 00185 for (i=0 ; i<blocks ; i++) { 00186 nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf); 00187 s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES); 00188 *data_size += NELLY_SAMPLES*sizeof(int16_t); 00189 } 00190 00191 return buf_size; 00192 } 00193 00194 static av_cold int decode_end(AVCodecContext * avctx) { 00195 NellyMoserDecodeContext *s = avctx->priv_data; 00196 00197 ff_mdct_end(&s->imdct_ctx); 00198 return 0; 00199 } 00200 00201 AVCodec nellymoser_decoder = { 00202 "nellymoser", 00203 AVMEDIA_TYPE_AUDIO, 00204 CODEC_ID_NELLYMOSER, 00205 sizeof(NellyMoserDecodeContext), 00206 decode_init, 00207 NULL, 00208 decode_end, 00209 decode_tag, 00210 .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"), 00211 }; 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