libavcodec/nellymoserdec.c

   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 nellymoserdec.c
  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/random.h"
  36 #include "avcodec.h"
  37 #include "dsputil.h"
  38
  39 #define ALT_BITSTREAM_READER_LE
  40 #include "bitstream.h"
  41
  42
  43 typedef struct NellyMoserDecodeContext {
  44     AVCodecContext* avctx;
  45     DECLARE_ALIGNED_16(float,float_buf[NELLY_SAMPLES]);
  46     float           state[128];
  47     AVRandomState   random_state;
  48     GetBitContext   gb;
  49     int             add_bias;
  50     float           scale_bias;
  51     DSPContext      dsp;
  52     MDCTContext     imdct_ctx;
  53     DECLARE_ALIGNED_16(float,imdct_out[NELLY_BUF_LEN * 2]);
  54 } NellyMoserDecodeContext;
  55
  56 static DECLARE_ALIGNED_16(float,sine_window[128]);
  57
  58 static 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]*sine_window[bot]
  67                     +state[bot]*sine_window[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
  75 static 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(&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_random(&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
 129 static av_cold int decode_init(AVCodecContext * avctx) {
 130     NellyMoserDecodeContext *s = avctx->priv_data;
 131
 132     s->avctx = avctx;
 133     av_init_random(0, &s->random_state);
 134     ff_mdct_init(&s->imdct_ctx, 8, 1);
 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 (!sine_window[0])
 148         ff_sine_window_init(sine_window, 128);
 149
 150     avctx->sample_fmt = SAMPLE_FMT_S16;
 151     return 0;
 152 }
 153
 154 static int decode_tag(AVCodecContext * avctx,
 155                       void *data, int *data_size,
 156                       const uint8_t * buf, int buf_size) {
 157     NellyMoserDecodeContext *s = avctx->priv_data;
 158     int blocks, i;
 159     int16_t* samples;
 160     *data_size = 0;
 161     samples = (int16_t*)data;
 162
 163     if (buf_size < avctx->block_align)
 164         return buf_size;
 165
 166     switch (buf_size) {
 167         case 64:    // 8000Hz
 168             blocks = 1; break;
 169         case 128:   // 11025Hz
 170             blocks = 2; break;
 171         case 256:   // 22050Hz
 172             blocks = 4; break;
 173         case 512:   // 44100Hz
 174             blocks = 8; break;
 175         default:
 176             av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
 177             return buf_size;
 178     }
 179
 180     for (i=0 ; i<blocks ; i++) {
 181         nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
 182         s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
 183         *data_size += NELLY_SAMPLES*sizeof(int16_t);
 184     }
 185
 186     return buf_size;
 187 }
 188
 189 static av_cold int decode_end(AVCodecContext * avctx) {
 190     NellyMoserDecodeContext *s = avctx->priv_data;
 191
 192     ff_mdct_end(&s->imdct_ctx);
 193     return 0;
 194 }
 195
 196 AVCodec nellymoser_decoder = {
 197     "nellymoser",
 198     CODEC_TYPE_AUDIO,
 199     CODEC_ID_NELLYMOSER,
 200     sizeof(NellyMoserDecodeContext),
 201     decode_init,
 202     NULL,
 203     decode_end,
 204     decode_tag,
 205     .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
 206 };
 207