| 1 | /* |
| 2 | * ADX ADPCM codecs |
| 3 | * Copyright (c) 2001,2003 BERO |
| 4 | * |
| 5 | * This file is part of FFmpeg. |
| 6 | * |
| 7 | * FFmpeg is free software; you can redistribute it and/or |
| 8 | * modify it under the terms of the GNU Lesser General Public |
| 9 | * License as published by the Free Software Foundation; either |
| 10 | * version 2.1 of the License, or (at your option) any later version. |
| 11 | * |
| 12 | * FFmpeg is distributed in the hope that it will be useful, |
| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 15 | * Lesser General Public License for more details. |
| 16 | * |
| 17 | * You should have received a copy of the GNU Lesser General Public |
| 18 | * License along with FFmpeg; if not, write to the Free Software |
| 19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 20 | */ |
| 21 | |
| 22 | #include "avcodec.h" |
| 23 | #include "adx.h" |
| 24 | #include "bytestream.h" |
| 25 | #include "internal.h" |
| 26 | #include "put_bits.h" |
| 27 | |
| 28 | /** |
| 29 | * @file |
| 30 | * SEGA CRI adx codecs. |
| 31 | * |
| 32 | * Reference documents: |
| 33 | * http://ku-www.ss.titech.ac.jp/~yatsushi/adx.html |
| 34 | * adx2wav & wav2adx http://www.geocities.co.jp/Playtown/2004/ |
| 35 | */ |
| 36 | |
| 37 | static void adx_encode(ADXContext *c, uint8_t *adx, const int16_t *wav, |
| 38 | ADXChannelState *prev, int channels) |
| 39 | { |
| 40 | PutBitContext pb; |
| 41 | int scale; |
| 42 | int i, j; |
| 43 | int s0, s1, s2, d; |
| 44 | int max = 0; |
| 45 | int min = 0; |
| 46 | |
| 47 | s1 = prev->s1; |
| 48 | s2 = prev->s2; |
| 49 | for (i = 0, j = 0; j < 32; i += channels, j++) { |
| 50 | s0 = wav[i]; |
| 51 | d = ((s0 << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; |
| 52 | if (max < d) |
| 53 | max = d; |
| 54 | if (min > d) |
| 55 | min = d; |
| 56 | s2 = s1; |
| 57 | s1 = s0; |
| 58 | } |
| 59 | |
| 60 | if (max == 0 && min == 0) { |
| 61 | prev->s1 = s1; |
| 62 | prev->s2 = s2; |
| 63 | memset(adx, 0, BLOCK_SIZE); |
| 64 | return; |
| 65 | } |
| 66 | |
| 67 | if (max / 7 > -min / 8) |
| 68 | scale = max / 7; |
| 69 | else |
| 70 | scale = -min / 8; |
| 71 | |
| 72 | if (scale == 0) |
| 73 | scale = 1; |
| 74 | |
| 75 | AV_WB16(adx, scale); |
| 76 | |
| 77 | init_put_bits(&pb, adx + 2, 16); |
| 78 | |
| 79 | s1 = prev->s1; |
| 80 | s2 = prev->s2; |
| 81 | for (i = 0, j = 0; j < 32; i += channels, j++) { |
| 82 | d = ((wav[i] << COEFF_BITS) - c->coeff[0] * s1 - c->coeff[1] * s2) >> COEFF_BITS; |
| 83 | |
| 84 | d = av_clip(ROUNDED_DIV(d, scale), -8, 7); |
| 85 | |
| 86 | put_sbits(&pb, 4, d); |
| 87 | |
| 88 | s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS; |
| 89 | s2 = s1; |
| 90 | s1 = s0; |
| 91 | } |
| 92 | prev->s1 = s1; |
| 93 | prev->s2 = s2; |
| 94 | |
| 95 | flush_put_bits(&pb); |
| 96 | } |
| 97 | |
| 98 | #define HEADER_SIZE 36 |
| 99 | |
| 100 | static int adx_encode_header(AVCodecContext *avctx, uint8_t *buf, int bufsize) |
| 101 | { |
| 102 | ADXContext *c = avctx->priv_data; |
| 103 | |
| 104 | bytestream_put_be16(&buf, 0x8000); /* header signature */ |
| 105 | bytestream_put_be16(&buf, HEADER_SIZE - 4); /* copyright offset */ |
| 106 | bytestream_put_byte(&buf, 3); /* encoding */ |
| 107 | bytestream_put_byte(&buf, BLOCK_SIZE); /* block size */ |
| 108 | bytestream_put_byte(&buf, 4); /* sample size */ |
| 109 | bytestream_put_byte(&buf, avctx->channels); /* channels */ |
| 110 | bytestream_put_be32(&buf, avctx->sample_rate); /* sample rate */ |
| 111 | bytestream_put_be32(&buf, 0); /* total sample count */ |
| 112 | bytestream_put_be16(&buf, c->cutoff); /* cutoff frequency */ |
| 113 | bytestream_put_byte(&buf, 3); /* version */ |
| 114 | bytestream_put_byte(&buf, 0); /* flags */ |
| 115 | bytestream_put_be32(&buf, 0); /* unknown */ |
| 116 | bytestream_put_be32(&buf, 0); /* loop enabled */ |
| 117 | bytestream_put_be16(&buf, 0); /* padding */ |
| 118 | bytestream_put_buffer(&buf, "(c)CRI", 6); /* copyright signature */ |
| 119 | |
| 120 | return HEADER_SIZE; |
| 121 | } |
| 122 | |
| 123 | static av_cold int adx_encode_init(AVCodecContext *avctx) |
| 124 | { |
| 125 | ADXContext *c = avctx->priv_data; |
| 126 | |
| 127 | if (avctx->channels > 2) { |
| 128 | av_log(avctx, AV_LOG_ERROR, "Invalid number of channels\n"); |
| 129 | return AVERROR(EINVAL); |
| 130 | } |
| 131 | avctx->frame_size = BLOCK_SAMPLES; |
| 132 | |
| 133 | /* the cutoff can be adjusted, but this seems to work pretty well */ |
| 134 | c->cutoff = 500; |
| 135 | ff_adx_calculate_coeffs(c->cutoff, avctx->sample_rate, COEFF_BITS, c->coeff); |
| 136 | |
| 137 | return 0; |
| 138 | } |
| 139 | |
| 140 | static int adx_encode_frame(AVCodecContext *avctx, AVPacket *avpkt, |
| 141 | const AVFrame *frame, int *got_packet_ptr) |
| 142 | { |
| 143 | ADXContext *c = avctx->priv_data; |
| 144 | const int16_t *samples = (const int16_t *)frame->data[0]; |
| 145 | uint8_t *dst; |
| 146 | int ch, out_size, ret; |
| 147 | |
| 148 | out_size = BLOCK_SIZE * avctx->channels + !c->header_parsed * HEADER_SIZE; |
| 149 | if ((ret = ff_alloc_packet2(avctx, avpkt, out_size)) < 0) |
| 150 | return ret; |
| 151 | dst = avpkt->data; |
| 152 | |
| 153 | if (!c->header_parsed) { |
| 154 | int hdrsize; |
| 155 | if ((hdrsize = adx_encode_header(avctx, dst, avpkt->size)) < 0) { |
| 156 | av_log(avctx, AV_LOG_ERROR, "output buffer is too small\n"); |
| 157 | return AVERROR(EINVAL); |
| 158 | } |
| 159 | dst += hdrsize; |
| 160 | c->header_parsed = 1; |
| 161 | } |
| 162 | |
| 163 | for (ch = 0; ch < avctx->channels; ch++) { |
| 164 | adx_encode(c, dst, samples + ch, &c->prev[ch], avctx->channels); |
| 165 | dst += BLOCK_SIZE; |
| 166 | } |
| 167 | |
| 168 | *got_packet_ptr = 1; |
| 169 | return 0; |
| 170 | } |
| 171 | |
| 172 | AVCodec ff_adpcm_adx_encoder = { |
| 173 | .name = "adpcm_adx", |
| 174 | .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), |
| 175 | .type = AVMEDIA_TYPE_AUDIO, |
| 176 | .id = AV_CODEC_ID_ADPCM_ADX, |
| 177 | .priv_data_size = sizeof(ADXContext), |
| 178 | .init = adx_encode_init, |
| 179 | .encode2 = adx_encode_frame, |
| 180 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16, |
| 181 | AV_SAMPLE_FMT_NONE }, |
| 182 | }; |