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
  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 "libavutil/channel_layout.h"
  35 #include "libavutil/float_dsp.h"
  36 #include "libavutil/lfg.h"
  37 #include "libavutil/random_seed.h"
  38
  39 #define BITSTREAM_READER_LE
  40 #include "avcodec.h"
  41 #include "bitstream.h"
  42 #include "fft.h"
  43 #include "internal.h"
  44 #include "nellymoser.h"
  45 #include "sinewin.h"
  46
  47
  48 typedef struct NellyMoserDecodeContext {
  49     AVCodecContext* avctx;
  50     AVLFG           random_state;
  51     BitstreamContext bc;
  52     float           scale_bias;
  53     AVFloatDSPContext fdsp;
  54     FFTContext      imdct_ctx;
  55     DECLARE_ALIGNED(32, float, imdct_buf)[2][NELLY_BUF_LEN];
  56     float          *imdct_out;
  57     float          *imdct_prev;
  58 } NellyMoserDecodeContext;
  59
  60 static void nelly_decode_block(NellyMoserDecodeContext *s,
  61                                const unsigned char block[NELLY_BLOCK_LEN],
  62                                float audio[NELLY_SAMPLES])
  63 {
  64     int i,j;
  65     float buf[NELLY_FILL_LEN], pows[NELLY_FILL_LEN];
  66     float *aptr, *bptr, *pptr, val, pval;
  67     int bits[NELLY_BUF_LEN];
  68     unsigned char v;
  69
  70     bitstream_init8(&s->bc, block, NELLY_BLOCK_LEN);
  71
  72     bptr = buf;
  73     pptr = pows;
  74     val = ff_nelly_init_table[bitstream_read(&s->bc, 6)];
  75     for (i=0 ; i<NELLY_BANDS ; i++) {
  76         if (i > 0)
  77             val += ff_nelly_delta_table[bitstream_read(&s->bc, 5)];
  78         pval = -pow(2, val/2048) * s->scale_bias;
  79         for (j = 0; j < ff_nelly_band_sizes_table[i]; j++) {
  80             *bptr++ = val;
  81             *pptr++ = pval;
  82         }
  83
  84     }
  85
  86     ff_nelly_get_sample_bits(buf, bits);
  87
  88     for (i = 0; i < 2; i++) {
  89         aptr = audio + i * NELLY_BUF_LEN;
  90
  91         bitstream_init8(&s->bc, block, NELLY_BLOCK_LEN);
  92         bitstream_skip(&s->bc, NELLY_HEADER_BITS + i * NELLY_DETAIL_BITS);
  93
  94         for (j = 0; j < NELLY_FILL_LEN; j++) {
  95             if (bits[j] <= 0) {
  96                 aptr[j] = M_SQRT1_2*pows[j];
  97                 if (av_lfg_get(&s->random_state) & 1)
  98                     aptr[j] *= -1.0;
  99             } else {
 100                 v = bitstream_read(&s->bc, bits[j]);
 101                 aptr[j] = ff_nelly_dequantization_table[(1<<bits[j])-1+v]*pows[j];
 102             }
 103         }
 104         memset(&aptr[NELLY_FILL_LEN], 0,
 105                (NELLY_BUF_LEN - NELLY_FILL_LEN) * sizeof(float));
 106
 107         s->imdct_ctx.imdct_half(&s->imdct_ctx, s->imdct_out, aptr);
 108         s->fdsp.vector_fmul_window(aptr, s->imdct_prev + NELLY_BUF_LEN / 2,
 109                                    s->imdct_out, ff_sine_128,
 110                                    NELLY_BUF_LEN / 2);
 111         FFSWAP(float *, s->imdct_out, s->imdct_prev);
 112     }
 113 }
 114
 115 static av_cold int decode_init(AVCodecContext * avctx) {
 116     NellyMoserDecodeContext *s = avctx->priv_data;
 117
 118     s->avctx = avctx;
 119     s->imdct_out = s->imdct_buf[0];
 120     s->imdct_prev = s->imdct_buf[1];
 121     av_lfg_init(&s->random_state, 0);
 122     ff_mdct_init(&s->imdct_ctx, 8, 1, 1.0);
 123
 124     avpriv_float_dsp_init(&s->fdsp, avctx->flags & AV_CODEC_FLAG_BITEXACT);
 125
 126     s->scale_bias = 1.0/(32768*8);
 127     avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
 128
 129     /* Generate overlap window */
 130     if (!ff_sine_128[127])
 131         ff_init_ff_sine_windows(7);
 132
 133     avctx->channels       = 1;
 134     avctx->channel_layout = AV_CH_LAYOUT_MONO;
 135
 136     return 0;
 137 }
 138
 139 static int decode_tag(AVCodecContext *avctx, void *data,
 140                       int *got_frame_ptr, AVPacket *avpkt)
 141 {
 142     AVFrame *frame     = data;
 143     const uint8_t *buf = avpkt->data;
 144     int buf_size = avpkt->size;
 145     NellyMoserDecodeContext *s = avctx->priv_data;
 146     int blocks, i, ret;
 147     float   *samples_flt;
 148
 149     blocks     = buf_size / NELLY_BLOCK_LEN;
 150     if (blocks <= 0) {
 151         av_log(avctx, AV_LOG_ERROR, "Packet is too small\n");
 152         return AVERROR_INVALIDDATA;
 153     }
 154     if (buf_size % NELLY_BLOCK_LEN) {
 155         av_log(avctx, AV_LOG_WARNING, "Leftover bytes: %d.\n",
 156                buf_size % NELLY_BLOCK_LEN);
 157     }
 158     /* Normal numbers of blocks for sample rates:
 159      *  8000 Hz - 1
 160      * 11025 Hz - 2
 161      * 16000 Hz - 3
 162      * 22050 Hz - 4
 163      * 44100 Hz - 8
 164      */
 165
 166     /* get output buffer */
 167     frame->nb_samples = NELLY_SAMPLES * blocks;
 168     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) {
 169         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 170         return ret;
 171     }
 172     samples_flt = (float *)frame->data[0];
 173
 174     for (i=0 ; i<blocks ; i++) {
 175         nelly_decode_block(s, buf, samples_flt);
 176         samples_flt += NELLY_SAMPLES;
 177         buf += NELLY_BLOCK_LEN;
 178     }
 179
 180     *got_frame_ptr = 1;
 181
 182     return buf_size;
 183 }
 184
 185 static av_cold int decode_end(AVCodecContext * avctx) {
 186     NellyMoserDecodeContext *s = avctx->priv_data;
 187
 188     ff_mdct_end(&s->imdct_ctx);
 189
 190     return 0;
 191 }
 192
 193 AVCodec ff_nellymoser_decoder = {
 194     .name           = "nellymoser",
 195     .long_name      = NULL_IF_CONFIG_SMALL("Nellymoser Asao"),
 196     .type           = AVMEDIA_TYPE_AUDIO,
 197     .id             = AV_CODEC_ID_NELLYMOSER,
 198     .priv_data_size = sizeof(NellyMoserDecodeContext),
 199     .init           = decode_init,
 200     .close          = decode_end,
 201     .decode         = decode_tag,
 202     .capabilities   = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_PARAM_CHANGE,
 203     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
 204                                                       AV_SAMPLE_FMT_NONE },
 205 };