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 libavcodec/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/lfg.h"
  36 #include "libavutil/random_seed.h"
  37 #include "avcodec.h"
  38 #include "dsputil.h"
  39
  40 #define ALT_BITSTREAM_READER_LE
  41 #include "get_bits.h"
  42
  43
  44 typedef struct NellyMoserDecodeContext {
  45     AVCodecContext* avctx;
  46     DECLARE_ALIGNED_16(float,float_buf[NELLY_SAMPLES]);
  47     float           state[128];
  48     AVLFG           random_state;
  49     GetBitContext   gb;
  50     int             add_bias;
  51     float           scale_bias;
  52     DSPContext      dsp;
  53     MDCTContext     imdct_ctx;
  54     DECLARE_ALIGNED_16(float,imdct_out[NELLY_BUF_LEN * 2]);
  55 } NellyMoserDecodeContext;
  56
  57 static void overlap_and_window(NellyMoserDecodeContext *s, float *state, float *audio, float *a_in)
  58 {
  59     int bot, top;
  60
  61     bot = 0;
  62     top = NELLY_BUF_LEN-1;
  63
  64     while (bot < NELLY_BUF_LEN) {
  65         audio[bot] = a_in [bot]*ff_sine_128[bot]
  66                     +state[bot]*ff_sine_128[top] + s->add_bias;
  67
  68         bot++;
  69         top--;
  70     }
  71     memcpy(state, a_in + NELLY_BUF_LEN, sizeof(float)*NELLY_BUF_LEN);
  72 }
  73
  74 static void nelly_decode_block(NellyMoserDecodeContext *s,
  75                                const unsigned char block[NELLY_BLOCK_LEN],
  76                                float audio[NELLY_SAMPLES])
  77 {
  78     int i,j;
  79     float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
  80     float *aptr, *bptr, *pptr, val, pval;
  81     int bits[NELLY_BUF_LEN];
  82     unsigned char v;
  83
  84     init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
  85
  86     bptr = buf;
  87     pptr = pows;
  88     val = ff_nelly_init_table[get_bits(&s->gb, 6)];
  89     for (i=0 ; i<NELLY_BANDS ; i++) {
  90         if (i > 0)
  91             val += ff_nelly_delta_table[get_bits(&s->gb, 5)];
  92         pval = -pow(2, val/2048) * s->scale_bias;
  93         for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
  94             *bptr++ = val;
  95             *pptr++ = pval;
  96         }
  97
  98     }
  99
 100     ff_nelly_get_sample_bits(buf, bits);
 101
 102     for (i = 0; i < 2; i++) {
 103         aptr = audio + i * NELLY_BUF_LEN;
 104
 105         init_get_bits(&s->gb, block, NELLY_BLOCK_LEN * 8);
 106         skip_bits_long(&s->gb, NELLY_HEADER_BITS + i*NELLY_DETAIL_BITS);
 107
 108         for (j = 0; j < NELLY_FILL_LEN; j++) {
 109             if (bits[j] <= 0) {
 110                 aptr[j] = M_SQRT1_2*pows[j];
 111                 if (av_lfg_get(&s->random_state) & 1)
 112                     aptr[j] *= -1.0;
 113             } else {
 114                 v = get_bits(&s->gb, bits[j]);
 115                 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
 116             }
 117         }
 118         memset(&aptr[NELLY_FILL_LEN], 0,
 119                (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
 120
 121         ff_imdct_calc(&s->imdct_ctx, s->imdct_out, aptr);
 122         /* XXX: overlapping and windowing should be part of a more
 123            generic imdct function */
 124         overlap_and_window(s, s->state, aptr, s->imdct_out);
 125     }
 126 }
 127
 128 static av_cold int decode_init(AVCodecContext * avctx) {
 129     NellyMoserDecodeContext *s = avctx->priv_data;
 130
 131     s->avctx = avctx;
 132     av_lfg_init(&s->random_state, ff_random_get_seed());
 133     ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
 134
 135     dsputil_init(&s->dsp, avctx);
 136
 137     if(s->dsp.float_to_int16 == ff_float_to_int16_c) {
 138         s->add_bias = 385;
 139         s->scale_bias = 1.0/(8*32768);
 140     } else {
 141         s->add_bias = 0;
 142         s->scale_bias = 1.0/(1*8);
 143     }
 144
 145     /* Generate overlap window */
 146     if (!ff_sine_128[127])
 147         ff_sine_window_init(ff_sine_128, 128);
 148
 149     avctx->sample_fmt = SAMPLE_FMT_S16;
 150     avctx->channel_layout = CH_LAYOUT_MONO;
 151     return 0;
 152 }
 153
 154 static int decode_tag(AVCodecContext * avctx,
 155                       void *data, int *data_size,
 156                       AVPacket *avpkt) {
 157     const uint8_t *buf = avpkt->data;
 158     int buf_size = avpkt->size;
 159     NellyMoserDecodeContext *s = avctx->priv_data;
 160     int blocks, i;
 161     int16_t* samples;
 162     *data_size = 0;
 163     samples = (int16_t*)data;
 164
 165     if (buf_size < avctx->block_align)
 166         return buf_size;
 167
 168     switch (buf_size) {
 169         case 64:    // 8000Hz
 170             blocks = 1; break;
 171         case 128:   // 11025Hz
 172             blocks = 2; break;
 173         case 192:   // 16000Hz
 174             blocks = 3; break;
 175         case 256:   // 22050Hz
 176             blocks = 4; break;
 177         case 512:   // 44100Hz
 178             blocks = 8; break;
 179         default:
 180             av_log(avctx, AV_LOG_DEBUG, "Tag size %d.\n", buf_size);
 181             return buf_size;
 182     }
 183
 184     for (i=0 ; i<blocks ; i++) {
 185         nelly_decode_block(s, &buf[i*NELLY_BLOCK_LEN], s->float_buf);
 186         s->dsp.float_to_int16(&samples[i*NELLY_SAMPLES], s->float_buf, NELLY_SAMPLES);
 187         *data_size += NELLY_SAMPLES*sizeof(int16_t);
 188     }
 189
 190     return buf_size;
 191 }
 192
 193 static av_cold int decode_end(AVCodecContext * avctx) {
 194     NellyMoserDecodeContext *s = avctx->priv_data;
 195
 196     ff_mdct_end(&s->imdct_ctx);
 197     return 0;
 198 }
 199
 200 AVCodec nellymoser_decoder = {
 201     "nellymoser",
 202     CODEC_TYPE_AUDIO,
 203     CODEC_ID_NELLYMOSER,
 204     sizeof(NellyMoserDecodeContext),
 205     decode_init,
 206     NULL,
 207     decode_end,
 208     decode_tag,
 209     .long_name = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
 210 };
 211