| 1 | /* |
| 2 | * Real Audio 1.0 (14.4K) |
| 3 | * |
| 4 | * Copyright (c) 2008 Vitor Sessak |
| 5 | * Copyright (c) 2003 Nick Kurshev |
| 6 | * Based on public domain decoder at http://www.honeypot.net/audio |
| 7 | * |
| 8 | * This file is part of FFmpeg. |
| 9 | * |
| 10 | * FFmpeg is free software; you can redistribute it and/or |
| 11 | * modify it under the terms of the GNU Lesser General Public |
| 12 | * License as published by the Free Software Foundation; either |
| 13 | * version 2.1 of the License, or (at your option) any later version. |
| 14 | * |
| 15 | * FFmpeg is distributed in the hope that it will be useful, |
| 16 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 17 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 18 | * Lesser General Public License for more details. |
| 19 | * |
| 20 | * You should have received a copy of the GNU Lesser General Public |
| 21 | * License along with FFmpeg; if not, write to the Free Software |
| 22 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 23 | */ |
| 24 | |
| 25 | #include "libavutil/channel_layout.h" |
| 26 | #include "avcodec.h" |
| 27 | #include "get_bits.h" |
| 28 | #include "internal.h" |
| 29 | #include "ra144.h" |
| 30 | |
| 31 | |
| 32 | static av_cold int ra144_decode_init(AVCodecContext * avctx) |
| 33 | { |
| 34 | RA144Context *ractx = avctx->priv_data; |
| 35 | |
| 36 | ractx->avctx = avctx; |
| 37 | ff_audiodsp_init(&ractx->adsp); |
| 38 | |
| 39 | ractx->lpc_coef[0] = ractx->lpc_tables[0]; |
| 40 | ractx->lpc_coef[1] = ractx->lpc_tables[1]; |
| 41 | |
| 42 | avctx->channels = 1; |
| 43 | avctx->channel_layout = AV_CH_LAYOUT_MONO; |
| 44 | avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
| 45 | |
| 46 | return 0; |
| 47 | } |
| 48 | |
| 49 | static void do_output_subblock(RA144Context *ractx, const int16_t *lpc_coefs, |
| 50 | int gval, GetBitContext *gb) |
| 51 | { |
| 52 | int cba_idx = get_bits(gb, 7); // index of the adaptive CB, 0 if none |
| 53 | int gain = get_bits(gb, 8); |
| 54 | int cb1_idx = get_bits(gb, 7); |
| 55 | int cb2_idx = get_bits(gb, 7); |
| 56 | |
| 57 | ff_subblock_synthesis(ractx, lpc_coefs, cba_idx, cb1_idx, cb2_idx, gval, |
| 58 | gain); |
| 59 | } |
| 60 | |
| 61 | /** Uncompress one block (20 bytes -> 160*2 bytes). */ |
| 62 | static int ra144_decode_frame(AVCodecContext * avctx, void *data, |
| 63 | int *got_frame_ptr, AVPacket *avpkt) |
| 64 | { |
| 65 | AVFrame *frame = data; |
| 66 | const uint8_t *buf = avpkt->data; |
| 67 | int buf_size = avpkt->size; |
| 68 | static const uint8_t sizes[LPC_ORDER] = {6, 5, 5, 4, 4, 3, 3, 3, 3, 2}; |
| 69 | unsigned int refl_rms[NBLOCKS]; // RMS of the reflection coefficients |
| 70 | int16_t block_coefs[NBLOCKS][LPC_ORDER]; // LPC coefficients of each sub-block |
| 71 | unsigned int lpc_refl[LPC_ORDER]; // LPC reflection coefficients of the frame |
| 72 | int i, j; |
| 73 | int ret; |
| 74 | int16_t *samples; |
| 75 | unsigned int energy; |
| 76 | |
| 77 | RA144Context *ractx = avctx->priv_data; |
| 78 | GetBitContext gb; |
| 79 | |
| 80 | if (buf_size < FRAME_SIZE) { |
| 81 | av_log(avctx, AV_LOG_ERROR, |
| 82 | "Frame too small (%d bytes). Truncated file?\n", buf_size); |
| 83 | *got_frame_ptr = 0; |
| 84 | return AVERROR_INVALIDDATA; |
| 85 | } |
| 86 | |
| 87 | /* get output buffer */ |
| 88 | frame->nb_samples = NBLOCKS * BLOCKSIZE; |
| 89 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 90 | return ret; |
| 91 | samples = (int16_t *)frame->data[0]; |
| 92 | |
| 93 | init_get_bits8(&gb, buf, FRAME_SIZE); |
| 94 | |
| 95 | for (i = 0; i < LPC_ORDER; i++) |
| 96 | lpc_refl[i] = ff_lpc_refl_cb[i][get_bits(&gb, sizes[i])]; |
| 97 | |
| 98 | ff_eval_coefs(ractx->lpc_coef[0], lpc_refl); |
| 99 | ractx->lpc_refl_rms[0] = ff_rms(lpc_refl); |
| 100 | |
| 101 | energy = ff_energy_tab[get_bits(&gb, 5)]; |
| 102 | |
| 103 | refl_rms[0] = ff_interp(ractx, block_coefs[0], 1, 1, ractx->old_energy); |
| 104 | refl_rms[1] = ff_interp(ractx, block_coefs[1], 2, |
| 105 | energy <= ractx->old_energy, |
| 106 | ff_t_sqrt(energy*ractx->old_energy) >> 12); |
| 107 | refl_rms[2] = ff_interp(ractx, block_coefs[2], 3, 0, energy); |
| 108 | refl_rms[3] = ff_rescale_rms(ractx->lpc_refl_rms[0], energy); |
| 109 | |
| 110 | ff_int_to_int16(block_coefs[3], ractx->lpc_coef[0]); |
| 111 | |
| 112 | for (i=0; i < NBLOCKS; i++) { |
| 113 | do_output_subblock(ractx, block_coefs[i], refl_rms[i], &gb); |
| 114 | |
| 115 | for (j=0; j < BLOCKSIZE; j++) |
| 116 | *samples++ = av_clip_int16(ractx->curr_sblock[j + 10] << 2); |
| 117 | } |
| 118 | |
| 119 | ractx->old_energy = energy; |
| 120 | ractx->lpc_refl_rms[1] = ractx->lpc_refl_rms[0]; |
| 121 | |
| 122 | FFSWAP(unsigned int *, ractx->lpc_coef[0], ractx->lpc_coef[1]); |
| 123 | |
| 124 | *got_frame_ptr = 1; |
| 125 | |
| 126 | return FRAME_SIZE; |
| 127 | } |
| 128 | |
| 129 | AVCodec ff_ra_144_decoder = { |
| 130 | .name = "real_144", |
| 131 | .long_name = NULL_IF_CONFIG_SMALL("RealAudio 1.0 (14.4K)"), |
| 132 | .type = AVMEDIA_TYPE_AUDIO, |
| 133 | .id = AV_CODEC_ID_RA_144, |
| 134 | .priv_data_size = sizeof(RA144Context), |
| 135 | .init = ra144_decode_init, |
| 136 | .decode = ra144_decode_frame, |
| 137 | .capabilities = CODEC_CAP_DR1, |
| 138 | }; |