yading@10: /*
yading@10:  * Atrac 1 compatible decoder
yading@10:  * Copyright (c) 2009 Maxim Poliakovski
yading@10:  * Copyright (c) 2009 Benjamin Larsson
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: /**
yading@10:  * @file
yading@10:  * Atrac 1 compatible decoder.
yading@10:  * This decoder handles raw ATRAC1 data and probably SDDS data.
yading@10:  */
yading@10: 
yading@10: /* Many thanks to Tim Craig for all the help! */
yading@10: 
yading@10: #include <math.h>
yading@10: #include <stddef.h>
yading@10: #include <stdio.h>
yading@10: 
yading@10: #include "libavutil/float_dsp.h"
yading@10: #include "avcodec.h"
yading@10: #include "get_bits.h"
yading@10: #include "fft.h"
yading@10: #include "internal.h"
yading@10: #include "sinewin.h"
yading@10: 
yading@10: #include "atrac.h"
yading@10: #include "atrac1data.h"
yading@10: 
yading@10: #define AT1_MAX_BFU      52                 ///< max number of block floating units in a sound unit
yading@10: #define AT1_SU_SIZE      212                ///< number of bytes in a sound unit
yading@10: #define AT1_SU_SAMPLES   512                ///< number of samples in a sound unit
yading@10: #define AT1_FRAME_SIZE   AT1_SU_SIZE * 2
yading@10: #define AT1_SU_MAX_BITS  AT1_SU_SIZE * 8
yading@10: #define AT1_MAX_CHANNELS 2
yading@10: 
yading@10: #define AT1_QMF_BANDS    3
yading@10: #define IDX_LOW_BAND     0
yading@10: #define IDX_MID_BAND     1
yading@10: #define IDX_HIGH_BAND    2
yading@10: 
yading@10: /**
yading@10:  * Sound unit struct, one unit is used per channel
yading@10:  */
yading@10: typedef struct {
yading@10:     int                 log2_block_count[AT1_QMF_BANDS];    ///< log2 number of blocks in a band
yading@10:     int                 num_bfus;                           ///< number of Block Floating Units
yading@10:     float*              spectrum[2];
yading@10:     DECLARE_ALIGNED(32, float, spec1)[AT1_SU_SAMPLES];     ///< mdct buffer
yading@10:     DECLARE_ALIGNED(32, float, spec2)[AT1_SU_SAMPLES];     ///< mdct buffer
yading@10:     DECLARE_ALIGNED(32, float, fst_qmf_delay)[46];         ///< delay line for the 1st stacked QMF filter
yading@10:     DECLARE_ALIGNED(32, float, snd_qmf_delay)[46];         ///< delay line for the 2nd stacked QMF filter
yading@10:     DECLARE_ALIGNED(32, float, last_qmf_delay)[256+23];    ///< delay line for the last stacked QMF filter
yading@10: } AT1SUCtx;
yading@10: 
yading@10: /**
yading@10:  * The atrac1 context, holds all needed parameters for decoding
yading@10:  */
yading@10: typedef struct {
yading@10:     AT1SUCtx            SUs[AT1_MAX_CHANNELS];              ///< channel sound unit
yading@10:     DECLARE_ALIGNED(32, float, spec)[AT1_SU_SAMPLES];      ///< the mdct spectrum buffer
yading@10: 
yading@10:     DECLARE_ALIGNED(32, float,  low)[256];
yading@10:     DECLARE_ALIGNED(32, float,  mid)[256];
yading@10:     DECLARE_ALIGNED(32, float, high)[512];
yading@10:     float*              bands[3];
yading@10:     FFTContext          mdct_ctx[3];
yading@10:     AVFloatDSPContext   fdsp;
yading@10: } AT1Ctx;
yading@10: 
yading@10: /** size of the transform in samples in the long mode for each QMF band */
yading@10: static const uint16_t samples_per_band[3] = {128, 128, 256};
yading@10: static const uint8_t   mdct_long_nbits[3] = {7, 7, 8};
yading@10: 
yading@10: 
yading@10: static void at1_imdct(AT1Ctx *q, float *spec, float *out, int nbits,
yading@10:                       int rev_spec)
yading@10: {
yading@10:     FFTContext* mdct_context = &q->mdct_ctx[nbits - 5 - (nbits > 6)];
yading@10:     int transf_size = 1 << nbits;
yading@10: 
yading@10:     if (rev_spec) {
yading@10:         int i;
yading@10:         for (i = 0; i < transf_size / 2; i++)
yading@10:             FFSWAP(float, spec[i], spec[transf_size - 1 - i]);
yading@10:     }
yading@10:     mdct_context->imdct_half(mdct_context, out, spec);
yading@10: }
yading@10: 
yading@10: 
yading@10: static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
yading@10: {
yading@10:     int          band_num, band_samples, log2_block_count, nbits, num_blocks, block_size;
yading@10:     unsigned int start_pos, ref_pos = 0, pos = 0;
yading@10: 
yading@10:     for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
yading@10:         float *prev_buf;
yading@10:         int j;
yading@10: 
yading@10:         band_samples = samples_per_band[band_num];
yading@10:         log2_block_count = su->log2_block_count[band_num];
yading@10: 
yading@10:         /* number of mdct blocks in the current QMF band: 1 - for long mode */
yading@10:         /* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
yading@10:         num_blocks = 1 << log2_block_count;
yading@10: 
yading@10:         if (num_blocks == 1) {
yading@10:             /* mdct block size in samples: 128 (long mode, low & mid bands), */
yading@10:             /* 256 (long mode, high band) and 32 (short mode, all bands) */
yading@10:             block_size = band_samples >> log2_block_count;
yading@10: 
yading@10:             /* calc transform size in bits according to the block_size_mode */
yading@10:             nbits = mdct_long_nbits[band_num] - log2_block_count;
yading@10: 
yading@10:             if (nbits != 5 && nbits != 7 && nbits != 8)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10:         } else {
yading@10:             block_size = 32;
yading@10:             nbits = 5;
yading@10:         }
yading@10: 
yading@10:         start_pos = 0;
yading@10:         prev_buf = &su->spectrum[1][ref_pos + band_samples - 16];
yading@10:         for (j=0; j < num_blocks; j++) {
yading@10:             at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], nbits, band_num);
yading@10: 
yading@10:             /* overlap and window */
yading@10:             q->fdsp.vector_fmul_window(&q->bands[band_num][start_pos], prev_buf,
yading@10:                                        &su->spectrum[0][ref_pos + start_pos], ff_sine_32, 16);
yading@10: 
yading@10:             prev_buf = &su->spectrum[0][ref_pos+start_pos + 16];
yading@10:             start_pos += block_size;
yading@10:             pos += block_size;
yading@10:         }
yading@10: 
yading@10:         if (num_blocks == 1)
yading@10:             memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
yading@10: 
yading@10:         ref_pos += band_samples;
yading@10:     }
yading@10: 
yading@10:     /* Swap buffers so the mdct overlap works */
yading@10:     FFSWAP(float*, su->spectrum[0], su->spectrum[1]);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: /**
yading@10:  * Parse the block size mode byte
yading@10:  */
yading@10: 
yading@10: static int at1_parse_bsm(GetBitContext* gb, int log2_block_cnt[AT1_QMF_BANDS])
yading@10: {
yading@10:     int log2_block_count_tmp, i;
yading@10: 
yading@10:     for (i = 0; i < 2; i++) {
yading@10:         /* low and mid band */
yading@10:         log2_block_count_tmp = get_bits(gb, 2);
yading@10:         if (log2_block_count_tmp & 1)
yading@10:             return AVERROR_INVALIDDATA;
yading@10:         log2_block_cnt[i] = 2 - log2_block_count_tmp;
yading@10:     }
yading@10: 
yading@10:     /* high band */
yading@10:     log2_block_count_tmp = get_bits(gb, 2);
yading@10:     if (log2_block_count_tmp != 0 && log2_block_count_tmp != 3)
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     log2_block_cnt[IDX_HIGH_BAND] = 3 - log2_block_count_tmp;
yading@10: 
yading@10:     skip_bits(gb, 2);
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: static int at1_unpack_dequant(GetBitContext* gb, AT1SUCtx* su,
yading@10:                               float spec[AT1_SU_SAMPLES])
yading@10: {
yading@10:     int bits_used, band_num, bfu_num, i;
yading@10:     uint8_t idwls[AT1_MAX_BFU];                 ///< the word length indexes for each BFU
yading@10:     uint8_t idsfs[AT1_MAX_BFU];                 ///< the scalefactor indexes for each BFU
yading@10: 
yading@10:     /* parse the info byte (2nd byte) telling how much BFUs were coded */
yading@10:     su->num_bfus = bfu_amount_tab1[get_bits(gb, 3)];
yading@10: 
yading@10:     /* calc number of consumed bits:
yading@10:         num_BFUs * (idwl(4bits) + idsf(6bits)) + log2_block_count(8bits) + info_byte(8bits)
yading@10:         + info_byte_copy(8bits) + log2_block_count_copy(8bits) */
yading@10:     bits_used = su->num_bfus * 10 + 32 +
yading@10:                 bfu_amount_tab2[get_bits(gb, 2)] +
yading@10:                 (bfu_amount_tab3[get_bits(gb, 3)] << 1);
yading@10: 
yading@10:     /* get word length index (idwl) for each BFU */
yading@10:     for (i = 0; i < su->num_bfus; i++)
yading@10:         idwls[i] = get_bits(gb, 4);
yading@10: 
yading@10:     /* get scalefactor index (idsf) for each BFU */
yading@10:     for (i = 0; i < su->num_bfus; i++)
yading@10:         idsfs[i] = get_bits(gb, 6);
yading@10: 
yading@10:     /* zero idwl/idsf for empty BFUs */
yading@10:     for (i = su->num_bfus; i < AT1_MAX_BFU; i++)
yading@10:         idwls[i] = idsfs[i] = 0;
yading@10: 
yading@10:     /* read in the spectral data and reconstruct MDCT spectrum of this channel */
yading@10:     for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
yading@10:         for (bfu_num = bfu_bands_t[band_num]; bfu_num < bfu_bands_t[band_num+1]; bfu_num++) {
yading@10:             int pos;
yading@10: 
yading@10:             int num_specs = specs_per_bfu[bfu_num];
yading@10:             int word_len  = !!idwls[bfu_num] + idwls[bfu_num];
yading@10:             float scale_factor = ff_atrac_sf_table[idsfs[bfu_num]];
yading@10:             bits_used += word_len * num_specs; /* add number of bits consumed by current BFU */
yading@10: 
yading@10:             /* check for bitstream overflow */
yading@10:             if (bits_used > AT1_SU_MAX_BITS)
yading@10:                 return AVERROR_INVALIDDATA;
yading@10: 
yading@10:             /* get the position of the 1st spec according to the block size mode */
yading@10:             pos = su->log2_block_count[band_num] ? bfu_start_short[bfu_num] : bfu_start_long[bfu_num];
yading@10: 
yading@10:             if (word_len) {
yading@10:                 float   max_quant = 1.0 / (float)((1 << (word_len - 1)) - 1);
yading@10: 
yading@10:                 for (i = 0; i < num_specs; i++) {
yading@10:                     /* read in a quantized spec and convert it to
yading@10:                      * signed int and then inverse quantization
yading@10:                      */
yading@10:                     spec[pos+i] = get_sbits(gb, word_len) * scale_factor * max_quant;
yading@10:                 }
yading@10:             } else { /* word_len = 0 -> empty BFU, zero all specs in the empty BFU */
yading@10:                 memset(&spec[pos], 0, num_specs * sizeof(float));
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: static void at1_subband_synthesis(AT1Ctx *q, AT1SUCtx* su, float *pOut)
yading@10: {
yading@10:     float temp[256];
yading@10:     float iqmf_temp[512 + 46];
yading@10: 
yading@10:     /* combine low and middle bands */
yading@10:     ff_atrac_iqmf(q->bands[0], q->bands[1], 128, temp, su->fst_qmf_delay, iqmf_temp);
yading@10: 
yading@10:     /* delay the signal of the high band by 23 samples */
yading@10:     memcpy( su->last_qmf_delay,    &su->last_qmf_delay[256], sizeof(float) *  23);
yading@10:     memcpy(&su->last_qmf_delay[23], q->bands[2],             sizeof(float) * 256);
yading@10: 
yading@10:     /* combine (low + middle) and high bands */
yading@10:     ff_atrac_iqmf(temp, su->last_qmf_delay, 256, pOut, su->snd_qmf_delay, iqmf_temp);
yading@10: }
yading@10: 
yading@10: 
yading@10: static int atrac1_decode_frame(AVCodecContext *avctx, void *data,
yading@10:                                int *got_frame_ptr, AVPacket *avpkt)
yading@10: {
yading@10:     AVFrame *frame     = data;
yading@10:     const uint8_t *buf = avpkt->data;
yading@10:     int buf_size       = avpkt->size;
yading@10:     AT1Ctx *q          = avctx->priv_data;
yading@10:     int ch, ret;
yading@10:     GetBitContext gb;
yading@10: 
yading@10: 
yading@10:     if (buf_size < 212 * avctx->channels) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Not enough data to decode!\n");
yading@10:         return AVERROR_INVALIDDATA;
yading@10:     }
yading@10: 
yading@10:     /* get output buffer */
yading@10:     frame->nb_samples = AT1_SU_SAMPLES;
yading@10:     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     for (ch = 0; ch < avctx->channels; ch++) {
yading@10:         AT1SUCtx* su = &q->SUs[ch];
yading@10: 
yading@10:         init_get_bits(&gb, &buf[212 * ch], 212 * 8);
yading@10: 
yading@10:         /* parse block_size_mode, 1st byte */
yading@10:         ret = at1_parse_bsm(&gb, su->log2_block_count);
yading@10:         if (ret < 0)
yading@10:             return ret;
yading@10: 
yading@10:         ret = at1_unpack_dequant(&gb, su, q->spec);
yading@10:         if (ret < 0)
yading@10:             return ret;
yading@10: 
yading@10:         ret = at1_imdct_block(su, q);
yading@10:         if (ret < 0)
yading@10:             return ret;
yading@10:         at1_subband_synthesis(q, su, (float *)frame->extended_data[ch]);
yading@10:     }
yading@10: 
yading@10:     *got_frame_ptr = 1;
yading@10: 
yading@10:     return avctx->block_align;
yading@10: }
yading@10: 
yading@10: 
yading@10: static av_cold int atrac1_decode_end(AVCodecContext * avctx)
yading@10: {
yading@10:     AT1Ctx *q = avctx->priv_data;
yading@10: 
yading@10:     ff_mdct_end(&q->mdct_ctx[0]);
yading@10:     ff_mdct_end(&q->mdct_ctx[1]);
yading@10:     ff_mdct_end(&q->mdct_ctx[2]);
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: static av_cold int atrac1_decode_init(AVCodecContext *avctx)
yading@10: {
yading@10:     AT1Ctx *q = avctx->priv_data;
yading@10:     int ret;
yading@10: 
yading@10:     avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
yading@10: 
yading@10:     if (avctx->channels < 1 || avctx->channels > AT1_MAX_CHANNELS) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Unsupported number of channels: %d\n",
yading@10:                avctx->channels);
yading@10:         return AVERROR(EINVAL);
yading@10:     }
yading@10: 
yading@10:     if (avctx->block_align <= 0) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Unsupported block align.");
yading@10:         return AVERROR_PATCHWELCOME;
yading@10:     }
yading@10: 
yading@10:     /* Init the mdct transforms */
yading@10:     if ((ret = ff_mdct_init(&q->mdct_ctx[0], 6, 1, -1.0/ (1 << 15))) ||
yading@10:         (ret = ff_mdct_init(&q->mdct_ctx[1], 8, 1, -1.0/ (1 << 15))) ||
yading@10:         (ret = ff_mdct_init(&q->mdct_ctx[2], 9, 1, -1.0/ (1 << 15)))) {
yading@10:         av_log(avctx, AV_LOG_ERROR, "Error initializing MDCT\n");
yading@10:         atrac1_decode_end(avctx);
yading@10:         return ret;
yading@10:     }
yading@10: 
yading@10:     ff_init_ff_sine_windows(5);
yading@10: 
yading@10:     ff_atrac_generate_tables();
yading@10: 
yading@10:     avpriv_float_dsp_init(&q->fdsp, avctx->flags & CODEC_FLAG_BITEXACT);
yading@10: 
yading@10:     q->bands[0] = q->low;
yading@10:     q->bands[1] = q->mid;
yading@10:     q->bands[2] = q->high;
yading@10: 
yading@10:     /* Prepare the mdct overlap buffers */
yading@10:     q->SUs[0].spectrum[0] = q->SUs[0].spec1;
yading@10:     q->SUs[0].spectrum[1] = q->SUs[0].spec2;
yading@10:     q->SUs[1].spectrum[0] = q->SUs[1].spec1;
yading@10:     q->SUs[1].spectrum[1] = q->SUs[1].spec2;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: 
yading@10: AVCodec ff_atrac1_decoder = {
yading@10:     .name           = "atrac1",
yading@10:     .type           = AVMEDIA_TYPE_AUDIO,
yading@10:     .id             = AV_CODEC_ID_ATRAC1,
yading@10:     .priv_data_size = sizeof(AT1Ctx),
yading@10:     .init           = atrac1_decode_init,
yading@10:     .close          = atrac1_decode_end,
yading@10:     .decode         = atrac1_decode_frame,
yading@10:     .capabilities   = CODEC_CAP_DR1,
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("Atrac 1 (Adaptive TRansform Acoustic Coding)"),
yading@10:     .sample_fmts    = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLTP,
yading@10:                                                       AV_SAMPLE_FMT_NONE },
yading@10: };