| 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 "libavutil/intreadwrite.h" |
| 23 | #include "avcodec.h" |
| 24 | #include "adx.h" |
| 25 | #include "get_bits.h" |
| 26 | #include "internal.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 av_cold int adx_decode_init(AVCodecContext *avctx) |
| 38 | { |
| 39 | ADXContext *c = avctx->priv_data; |
| 40 | int ret, header_size; |
| 41 | |
| 42 | if (avctx->extradata_size >= 24) { |
| 43 | if ((ret = ff_adx_decode_header(avctx, avctx->extradata, |
| 44 | avctx->extradata_size, &header_size, |
| 45 | c->coeff)) < 0) { |
| 46 | av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); |
| 47 | return AVERROR_INVALIDDATA; |
| 48 | } |
| 49 | c->channels = avctx->channels; |
| 50 | c->header_parsed = 1; |
| 51 | } |
| 52 | |
| 53 | avctx->sample_fmt = AV_SAMPLE_FMT_S16P; |
| 54 | |
| 55 | return 0; |
| 56 | } |
| 57 | |
| 58 | /** |
| 59 | * Decode 32 samples from 18 bytes. |
| 60 | * |
| 61 | * A 16-bit scalar value is applied to 32 residuals, which then have a |
| 62 | * 2nd-order LPC filter applied to it to form the output signal for a single |
| 63 | * channel. |
| 64 | */ |
| 65 | static int adx_decode(ADXContext *c, int16_t *out, int offset, |
| 66 | const uint8_t *in, int ch) |
| 67 | { |
| 68 | ADXChannelState *prev = &c->prev[ch]; |
| 69 | GetBitContext gb; |
| 70 | int scale = AV_RB16(in); |
| 71 | int i; |
| 72 | int s0, s1, s2, d; |
| 73 | |
| 74 | /* check if this is an EOF packet */ |
| 75 | if (scale & 0x8000) |
| 76 | return -1; |
| 77 | |
| 78 | init_get_bits(&gb, in + 2, (BLOCK_SIZE - 2) * 8); |
| 79 | out += offset; |
| 80 | s1 = prev->s1; |
| 81 | s2 = prev->s2; |
| 82 | for (i = 0; i < BLOCK_SAMPLES; i++) { |
| 83 | d = get_sbits(&gb, 4); |
| 84 | s0 = ((d << COEFF_BITS) * scale + c->coeff[0] * s1 + c->coeff[1] * s2) >> COEFF_BITS; |
| 85 | s2 = s1; |
| 86 | s1 = av_clip_int16(s0); |
| 87 | *out++ = s1; |
| 88 | } |
| 89 | prev->s1 = s1; |
| 90 | prev->s2 = s2; |
| 91 | |
| 92 | return 0; |
| 93 | } |
| 94 | |
| 95 | static int adx_decode_frame(AVCodecContext *avctx, void *data, |
| 96 | int *got_frame_ptr, AVPacket *avpkt) |
| 97 | { |
| 98 | AVFrame *frame = data; |
| 99 | int buf_size = avpkt->size; |
| 100 | ADXContext *c = avctx->priv_data; |
| 101 | int16_t **samples; |
| 102 | int samples_offset; |
| 103 | const uint8_t *buf = avpkt->data; |
| 104 | const uint8_t *buf_end = buf + avpkt->size; |
| 105 | int num_blocks, ch, ret; |
| 106 | |
| 107 | if (c->eof) { |
| 108 | *got_frame_ptr = 0; |
| 109 | return buf_size; |
| 110 | } |
| 111 | |
| 112 | if (!c->header_parsed && buf_size >= 2 && AV_RB16(buf) == 0x8000) { |
| 113 | int header_size; |
| 114 | if ((ret = ff_adx_decode_header(avctx, buf, buf_size, &header_size, |
| 115 | c->coeff)) < 0) { |
| 116 | av_log(avctx, AV_LOG_ERROR, "error parsing ADX header\n"); |
| 117 | return AVERROR_INVALIDDATA; |
| 118 | } |
| 119 | c->channels = avctx->channels; |
| 120 | c->header_parsed = 1; |
| 121 | if (buf_size < header_size) |
| 122 | return AVERROR_INVALIDDATA; |
| 123 | buf += header_size; |
| 124 | buf_size -= header_size; |
| 125 | } |
| 126 | if (!c->header_parsed) |
| 127 | return AVERROR_INVALIDDATA; |
| 128 | |
| 129 | /* calculate number of blocks in the packet */ |
| 130 | num_blocks = buf_size / (BLOCK_SIZE * c->channels); |
| 131 | |
| 132 | /* if the packet is not an even multiple of BLOCK_SIZE, check for an EOF |
| 133 | packet */ |
| 134 | if (!num_blocks || buf_size % (BLOCK_SIZE * avctx->channels)) { |
| 135 | if (buf_size >= 4 && (AV_RB16(buf) & 0x8000)) { |
| 136 | c->eof = 1; |
| 137 | *got_frame_ptr = 0; |
| 138 | return avpkt->size; |
| 139 | } |
| 140 | return AVERROR_INVALIDDATA; |
| 141 | } |
| 142 | |
| 143 | /* get output buffer */ |
| 144 | frame->nb_samples = num_blocks * BLOCK_SAMPLES; |
| 145 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 146 | return ret; |
| 147 | samples = (int16_t **)frame->extended_data; |
| 148 | samples_offset = 0; |
| 149 | |
| 150 | while (num_blocks--) { |
| 151 | for (ch = 0; ch < c->channels; ch++) { |
| 152 | if (buf_end - buf < BLOCK_SIZE || adx_decode(c, samples[ch], samples_offset, buf, ch)) { |
| 153 | c->eof = 1; |
| 154 | buf = avpkt->data + avpkt->size; |
| 155 | break; |
| 156 | } |
| 157 | buf_size -= BLOCK_SIZE; |
| 158 | buf += BLOCK_SIZE; |
| 159 | } |
| 160 | if (!c->eof) |
| 161 | samples_offset += BLOCK_SAMPLES; |
| 162 | } |
| 163 | |
| 164 | frame->nb_samples = samples_offset; |
| 165 | *got_frame_ptr = 1; |
| 166 | |
| 167 | return buf - avpkt->data; |
| 168 | } |
| 169 | |
| 170 | static void adx_decode_flush(AVCodecContext *avctx) |
| 171 | { |
| 172 | ADXContext *c = avctx->priv_data; |
| 173 | memset(c->prev, 0, sizeof(c->prev)); |
| 174 | c->eof = 0; |
| 175 | } |
| 176 | |
| 177 | AVCodec ff_adpcm_adx_decoder = { |
| 178 | .name = "adpcm_adx", |
| 179 | .long_name = NULL_IF_CONFIG_SMALL("SEGA CRI ADX ADPCM"), |
| 180 | .type = AVMEDIA_TYPE_AUDIO, |
| 181 | .id = AV_CODEC_ID_ADPCM_ADX, |
| 182 | .priv_data_size = sizeof(ADXContext), |
| 183 | .init = adx_decode_init, |
| 184 | .decode = adx_decode_frame, |
| 185 | .flush = adx_decode_flush, |
| 186 | .capabilities = CODEC_CAP_DR1, |
| 187 | .sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_S16P, |
| 188 | AV_SAMPLE_FMT_NONE }, |
| 189 | }; |