| 1 | /* |
| 2 | * Westwood SNDx codecs |
| 3 | * Copyright (c) 2005 Konstantin Shishkov |
| 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 <stdint.h> |
| 23 | |
| 24 | #include "libavutil/channel_layout.h" |
| 25 | #include "libavutil/common.h" |
| 26 | #include "libavutil/intreadwrite.h" |
| 27 | #include "avcodec.h" |
| 28 | #include "internal.h" |
| 29 | |
| 30 | /** |
| 31 | * @file |
| 32 | * Westwood SNDx codecs |
| 33 | * |
| 34 | * Reference documents about VQA format and its audio codecs |
| 35 | * can be found here: |
| 36 | * http://www.multimedia.cx |
| 37 | */ |
| 38 | |
| 39 | static const int8_t ws_adpcm_4bit[] = { |
| 40 | -9, -8, -6, -5, -4, -3, -2, -1, |
| 41 | 0, 1, 2, 3, 4, 5, 6, 8 |
| 42 | }; |
| 43 | |
| 44 | static av_cold int ws_snd_decode_init(AVCodecContext *avctx) |
| 45 | { |
| 46 | avctx->channels = 1; |
| 47 | avctx->channel_layout = AV_CH_LAYOUT_MONO; |
| 48 | avctx->sample_fmt = AV_SAMPLE_FMT_U8; |
| 49 | |
| 50 | return 0; |
| 51 | } |
| 52 | |
| 53 | static int ws_snd_decode_frame(AVCodecContext *avctx, void *data, |
| 54 | int *got_frame_ptr, AVPacket *avpkt) |
| 55 | { |
| 56 | AVFrame *frame = data; |
| 57 | const uint8_t *buf = avpkt->data; |
| 58 | int buf_size = avpkt->size; |
| 59 | |
| 60 | int in_size, out_size, ret; |
| 61 | int sample = 128; |
| 62 | uint8_t *samples; |
| 63 | uint8_t *samples_end; |
| 64 | |
| 65 | if (!buf_size) |
| 66 | return 0; |
| 67 | |
| 68 | if (buf_size < 4) { |
| 69 | av_log(avctx, AV_LOG_ERROR, "packet is too small\n"); |
| 70 | return AVERROR(EINVAL); |
| 71 | } |
| 72 | |
| 73 | out_size = AV_RL16(&buf[0]); |
| 74 | in_size = AV_RL16(&buf[2]); |
| 75 | buf += 4; |
| 76 | |
| 77 | if (in_size > buf_size) { |
| 78 | av_log(avctx, AV_LOG_ERROR, "Frame data is larger than input buffer\n"); |
| 79 | return AVERROR_INVALIDDATA; |
| 80 | } |
| 81 | |
| 82 | /* get output buffer */ |
| 83 | frame->nb_samples = out_size; |
| 84 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 85 | return ret; |
| 86 | samples = frame->data[0]; |
| 87 | samples_end = samples + out_size; |
| 88 | |
| 89 | if (in_size == out_size) { |
| 90 | memcpy(samples, buf, out_size); |
| 91 | *got_frame_ptr = 1; |
| 92 | return buf_size; |
| 93 | } |
| 94 | |
| 95 | while (samples < samples_end && buf - avpkt->data < buf_size) { |
| 96 | int code, smp, size; |
| 97 | uint8_t count; |
| 98 | code = *buf >> 6; |
| 99 | count = *buf & 0x3F; |
| 100 | buf++; |
| 101 | |
| 102 | /* make sure we don't write past the output buffer */ |
| 103 | switch (code) { |
| 104 | case 0: smp = 4 * (count + 1); break; |
| 105 | case 1: smp = 2 * (count + 1); break; |
| 106 | case 2: smp = (count & 0x20) ? 1 : count + 1; break; |
| 107 | default: smp = count + 1; break; |
| 108 | } |
| 109 | if (samples_end - samples < smp) |
| 110 | break; |
| 111 | |
| 112 | /* make sure we don't read past the input buffer */ |
| 113 | size = ((code == 2 && (count & 0x20)) || code == 3) ? 0 : count + 1; |
| 114 | if ((buf - avpkt->data) + size > buf_size) |
| 115 | break; |
| 116 | |
| 117 | switch (code) { |
| 118 | case 0: /* ADPCM 2-bit */ |
| 119 | for (count++; count > 0; count--) { |
| 120 | code = *buf++; |
| 121 | sample += ( code & 0x3) - 2; |
| 122 | sample = av_clip_uint8(sample); |
| 123 | *samples++ = sample; |
| 124 | sample += ((code >> 2) & 0x3) - 2; |
| 125 | sample = av_clip_uint8(sample); |
| 126 | *samples++ = sample; |
| 127 | sample += ((code >> 4) & 0x3) - 2; |
| 128 | sample = av_clip_uint8(sample); |
| 129 | *samples++ = sample; |
| 130 | sample += (code >> 6) - 2; |
| 131 | sample = av_clip_uint8(sample); |
| 132 | *samples++ = sample; |
| 133 | } |
| 134 | break; |
| 135 | case 1: /* ADPCM 4-bit */ |
| 136 | for (count++; count > 0; count--) { |
| 137 | code = *buf++; |
| 138 | sample += ws_adpcm_4bit[code & 0xF]; |
| 139 | sample = av_clip_uint8(sample); |
| 140 | *samples++ = sample; |
| 141 | sample += ws_adpcm_4bit[code >> 4]; |
| 142 | sample = av_clip_uint8(sample); |
| 143 | *samples++ = sample; |
| 144 | } |
| 145 | break; |
| 146 | case 2: /* no compression */ |
| 147 | if (count & 0x20) { /* big delta */ |
| 148 | int8_t t; |
| 149 | t = count; |
| 150 | t <<= 3; |
| 151 | sample += t >> 3; |
| 152 | sample = av_clip_uint8(sample); |
| 153 | *samples++ = sample; |
| 154 | } else { /* copy */ |
| 155 | memcpy(samples, buf, smp); |
| 156 | samples += smp; |
| 157 | buf += smp; |
| 158 | sample = buf[-1]; |
| 159 | } |
| 160 | break; |
| 161 | default: /* run */ |
| 162 | memset(samples, sample, smp); |
| 163 | samples += smp; |
| 164 | } |
| 165 | } |
| 166 | |
| 167 | frame->nb_samples = samples - frame->data[0]; |
| 168 | *got_frame_ptr = 1; |
| 169 | |
| 170 | return buf_size; |
| 171 | } |
| 172 | |
| 173 | AVCodec ff_ws_snd1_decoder = { |
| 174 | .name = "ws_snd1", |
| 175 | .long_name = NULL_IF_CONFIG_SMALL("Westwood Audio (SND1)"), |
| 176 | .type = AVMEDIA_TYPE_AUDIO, |
| 177 | .id = AV_CODEC_ID_WESTWOOD_SND1, |
| 178 | .init = ws_snd_decode_init, |
| 179 | .decode = ws_snd_decode_frame, |
| 180 | .capabilities = CODEC_CAP_DR1, |
| 181 | }; |