| 1 | /* |
| 2 | * LPCM codecs for PCM formats found in Video DVD streams |
| 3 | * Copyright (c) 2013 Christian Schmidt |
| 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 | /** |
| 23 | * @file |
| 24 | * LPCM codecs for PCM formats found in Video DVD streams |
| 25 | */ |
| 26 | |
| 27 | #include "avcodec.h" |
| 28 | #include "bytestream.h" |
| 29 | #include "internal.h" |
| 30 | |
| 31 | typedef struct PCMDVDContext { |
| 32 | uint32_t last_header; // Cached header to see if parsing is needed |
| 33 | int block_size; // Size of a block of samples in bytes |
| 34 | int last_block_size; // Size of the last block of samples in bytes |
| 35 | int samples_per_block; // Number of samples per channel per block |
| 36 | int groups_per_block; // Number of 20/24bit sample groups per block |
| 37 | uint8_t *extra_samples; // Pointer to leftover samples from a frame |
| 38 | int extra_sample_count; // Number of leftover samples in the buffer |
| 39 | } PCMDVDContext; |
| 40 | |
| 41 | static av_cold int pcm_dvd_decode_init(AVCodecContext *avctx) |
| 42 | { |
| 43 | PCMDVDContext *s = avctx->priv_data; |
| 44 | |
| 45 | /* Invalid header to force parsing of the first header */ |
| 46 | s->last_header = -1; |
| 47 | /* reserve space for 8 channels, 3 bytes/sample, 4 samples/block */ |
| 48 | if (!(s->extra_samples = av_malloc(8 * 3 * 4))) |
| 49 | return AVERROR(ENOMEM); |
| 50 | |
| 51 | return 0; |
| 52 | } |
| 53 | |
| 54 | static av_cold int pcm_dvd_decode_uninit(AVCodecContext *avctx) |
| 55 | { |
| 56 | PCMDVDContext *s = avctx->priv_data; |
| 57 | |
| 58 | av_freep(&s->extra_samples); |
| 59 | |
| 60 | return 0; |
| 61 | } |
| 62 | |
| 63 | static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header) |
| 64 | { |
| 65 | /* no traces of 44100 and 32000Hz in any commercial software or player */ |
| 66 | static const uint32_t frequencies[4] = { 48000, 96000, 44100, 32000 }; |
| 67 | PCMDVDContext *s = avctx->priv_data; |
| 68 | int header_int = (header[0] & 0xe0) | (header[1] << 8) | (header[2] << 16); |
| 69 | |
| 70 | /* early exit if the header didn't change apart from the frame number */ |
| 71 | if (s->last_header == header_int) |
| 72 | return 0; |
| 73 | s->last_header = -1; |
| 74 | |
| 75 | if (avctx->debug & FF_DEBUG_PICT_INFO) |
| 76 | av_dlog(avctx, "pcm_dvd_parse_header: header = %02x%02x%02x\n", |
| 77 | header[0], header[1], header[2]); |
| 78 | /* |
| 79 | * header[0] emphasis (1), muse(1), reserved(1), frame number(5) |
| 80 | * header[1] quant (2), freq(2), reserved(1), channels(3) |
| 81 | * header[2] dynamic range control (0x80 = off) |
| 82 | */ |
| 83 | |
| 84 | /* Discard potentially existing leftover samples from old channel layout */ |
| 85 | s->extra_sample_count = 0; |
| 86 | |
| 87 | /* get the sample depth and derive the sample format from it */ |
| 88 | avctx->bits_per_coded_sample = 16 + (header[1] >> 6 & 3) * 4; |
| 89 | if (avctx->bits_per_coded_sample == 28) { |
| 90 | av_log(avctx, AV_LOG_ERROR, |
| 91 | "PCM DVD unsupported sample depth %i\n", |
| 92 | avctx->bits_per_coded_sample); |
| 93 | return AVERROR_INVALIDDATA; |
| 94 | } |
| 95 | avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 |
| 96 | : AV_SAMPLE_FMT_S32; |
| 97 | avctx->bits_per_raw_sample = avctx->bits_per_coded_sample; |
| 98 | |
| 99 | /* get the sample rate */ |
| 100 | avctx->sample_rate = frequencies[header[1] >> 4 & 3]; |
| 101 | |
| 102 | /* get the number of channels */ |
| 103 | avctx->channels = 1 + (header[1] & 7); |
| 104 | /* calculate the bitrate */ |
| 105 | avctx->bit_rate = avctx->channels * |
| 106 | avctx->sample_rate * |
| 107 | avctx->bits_per_coded_sample; |
| 108 | |
| 109 | /* 4 samples form a group in 20/24bit PCM on DVD Video. |
| 110 | * A block is formed by the number of groups that are |
| 111 | * needed to complete a set of samples for each channel. */ |
| 112 | if (avctx->bits_per_coded_sample == 16) { |
| 113 | s->samples_per_block = 1; |
| 114 | s->block_size = avctx->channels * 2; |
| 115 | } else { |
| 116 | switch (avctx->channels) { |
| 117 | case 1: |
| 118 | case 2: |
| 119 | case 4: |
| 120 | /* one group has all the samples needed */ |
| 121 | s->block_size = 4 * avctx->bits_per_coded_sample / 8; |
| 122 | s->samples_per_block = 4 / avctx->channels; |
| 123 | s->groups_per_block = 1; |
| 124 | break; |
| 125 | case 8: |
| 126 | /* two groups have all the samples needed */ |
| 127 | s->block_size = 8 * avctx->bits_per_coded_sample / 8; |
| 128 | s->samples_per_block = 1; |
| 129 | s->groups_per_block = 2; |
| 130 | break; |
| 131 | default: |
| 132 | /* need avctx->channels groups */ |
| 133 | s->block_size = 4 * avctx->channels * |
| 134 | avctx->bits_per_coded_sample / 8; |
| 135 | s->samples_per_block = 4; |
| 136 | s->groups_per_block = avctx->channels; |
| 137 | break; |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | if (avctx->debug & FF_DEBUG_PICT_INFO) |
| 142 | av_dlog(avctx, |
| 143 | "pcm_dvd_parse_header: %d channels, %d bits per sample, %d Hz, %d bit/s\n", |
| 144 | avctx->channels, avctx->bits_per_coded_sample, |
| 145 | avctx->sample_rate, avctx->bit_rate); |
| 146 | |
| 147 | s->last_header = header_int; |
| 148 | |
| 149 | return 0; |
| 150 | } |
| 151 | |
| 152 | static void *pcm_dvd_decode_samples(AVCodecContext *avctx, const uint8_t *src, |
| 153 | void *dst, int blocks) |
| 154 | { |
| 155 | PCMDVDContext *s = avctx->priv_data; |
| 156 | int16_t *dst16 = dst; |
| 157 | int32_t *dst32 = dst; |
| 158 | GetByteContext gb; |
| 159 | int i; |
| 160 | uint8_t t; |
| 161 | int samples; |
| 162 | |
| 163 | bytestream2_init(&gb, src, blocks * s->block_size); |
| 164 | switch (avctx->bits_per_coded_sample) { |
| 165 | case 16: |
| 166 | #if HAVE_BIGENDIAN |
| 167 | bytestream2_get_buffer(&gb, dst16, blocks * s->block_size); |
| 168 | dst16 += blocks * s->block_size / 2; |
| 169 | #else |
| 170 | samples = blocks * avctx->channels; |
| 171 | do { |
| 172 | *dst16++ = bytestream2_get_be16u(&gb); |
| 173 | } while (--samples); |
| 174 | #endif |
| 175 | return dst16; |
| 176 | case 20: |
| 177 | if (avctx->channels == 1) { |
| 178 | do { |
| 179 | for (i = 2; i; i--) { |
| 180 | dst32[0] = bytestream2_get_be16u(&gb) << 16; |
| 181 | dst32[1] = bytestream2_get_be16u(&gb) << 16; |
| 182 | t = bytestream2_get_byteu(&gb); |
| 183 | *dst32++ += (t & 0xf0) << 8; |
| 184 | *dst32++ += (t & 0x0f) << 12; |
| 185 | } |
| 186 | } while (--blocks); |
| 187 | } else { |
| 188 | do { |
| 189 | for (i = s->groups_per_block; i; i--) { |
| 190 | dst32[0] = bytestream2_get_be16u(&gb) << 16; |
| 191 | dst32[1] = bytestream2_get_be16u(&gb) << 16; |
| 192 | dst32[2] = bytestream2_get_be16u(&gb) << 16; |
| 193 | dst32[3] = bytestream2_get_be16u(&gb) << 16; |
| 194 | t = bytestream2_get_byteu(&gb); |
| 195 | *dst32++ += (t & 0xf0) << 8; |
| 196 | *dst32++ += (t & 0x0f) << 12; |
| 197 | t = bytestream2_get_byteu(&gb); |
| 198 | *dst32++ += (t & 0xf0) << 8; |
| 199 | *dst32++ += (t & 0x0f) << 12; |
| 200 | } |
| 201 | } while (--blocks); |
| 202 | } |
| 203 | return dst32; |
| 204 | case 24: |
| 205 | if (avctx->channels == 1) { |
| 206 | do { |
| 207 | for (i = 2; i; i--) { |
| 208 | dst32[0] = bytestream2_get_be16u(&gb) << 16; |
| 209 | dst32[1] = bytestream2_get_be16u(&gb) << 16; |
| 210 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 211 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 212 | } |
| 213 | } while (--blocks); |
| 214 | } else { |
| 215 | do { |
| 216 | for (i = s->groups_per_block; i; i--) { |
| 217 | dst32[0] = bytestream2_get_be16u(&gb) << 16; |
| 218 | dst32[1] = bytestream2_get_be16u(&gb) << 16; |
| 219 | dst32[2] = bytestream2_get_be16u(&gb) << 16; |
| 220 | dst32[3] = bytestream2_get_be16u(&gb) << 16; |
| 221 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 222 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 223 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 224 | *dst32++ += bytestream2_get_byteu(&gb) << 8; |
| 225 | } |
| 226 | } while (--blocks); |
| 227 | } |
| 228 | return dst32; |
| 229 | default: |
| 230 | return NULL; |
| 231 | } |
| 232 | } |
| 233 | |
| 234 | static int pcm_dvd_decode_frame(AVCodecContext *avctx, void *data, |
| 235 | int *got_frame_ptr, AVPacket *avpkt) |
| 236 | { |
| 237 | AVFrame *frame = data; |
| 238 | const uint8_t *src = avpkt->data; |
| 239 | int buf_size = avpkt->size; |
| 240 | PCMDVDContext *s = avctx->priv_data; |
| 241 | int retval; |
| 242 | int blocks; |
| 243 | void *dst; |
| 244 | |
| 245 | if (buf_size < 3) { |
| 246 | av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n"); |
| 247 | return AVERROR_INVALIDDATA; |
| 248 | } |
| 249 | |
| 250 | if ((retval = pcm_dvd_parse_header(avctx, src))) |
| 251 | return retval; |
| 252 | if (s->last_block_size && s->last_block_size != s->block_size) { |
| 253 | av_log(avctx, AV_LOG_WARNING, "block_size has changed %d != %d\n", s->last_block_size, s->block_size); |
| 254 | s->extra_sample_count = 0; |
| 255 | } |
| 256 | s->last_block_size = s->block_size; |
| 257 | src += 3; |
| 258 | buf_size -= 3; |
| 259 | |
| 260 | blocks = (buf_size + s->extra_sample_count) / s->block_size; |
| 261 | |
| 262 | /* get output buffer */ |
| 263 | frame->nb_samples = blocks * s->samples_per_block; |
| 264 | if ((retval = ff_get_buffer(avctx, frame, 0)) < 0) |
| 265 | return retval; |
| 266 | dst = frame->data[0]; |
| 267 | |
| 268 | /* consume leftover samples from last packet */ |
| 269 | if (s->extra_sample_count) { |
| 270 | int missing_samples = s->block_size - s->extra_sample_count; |
| 271 | if (buf_size >= missing_samples) { |
| 272 | memcpy(s->extra_samples + s->extra_sample_count, src, |
| 273 | missing_samples); |
| 274 | dst = pcm_dvd_decode_samples(avctx, s->extra_samples, dst, 1); |
| 275 | src += missing_samples; |
| 276 | buf_size -= missing_samples; |
| 277 | s->extra_sample_count = 0; |
| 278 | blocks--; |
| 279 | } else { |
| 280 | /* new packet still doesn't have enough samples */ |
| 281 | memcpy(s->extra_samples + s->extra_sample_count, src, buf_size); |
| 282 | s->extra_sample_count += buf_size; |
| 283 | return avpkt->size; |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | /* decode remaining complete samples */ |
| 288 | if (blocks) { |
| 289 | pcm_dvd_decode_samples(avctx, src, dst, blocks); |
| 290 | buf_size -= blocks * s->block_size; |
| 291 | } |
| 292 | |
| 293 | /* store leftover samples */ |
| 294 | if (buf_size) { |
| 295 | src += blocks * s->block_size; |
| 296 | memcpy(s->extra_samples, src, buf_size); |
| 297 | s->extra_sample_count = buf_size; |
| 298 | } |
| 299 | |
| 300 | *got_frame_ptr = 1; |
| 301 | |
| 302 | return avpkt->size; |
| 303 | } |
| 304 | |
| 305 | AVCodec ff_pcm_dvd_decoder = { |
| 306 | .name = "pcm_dvd", |
| 307 | .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"), |
| 308 | .type = AVMEDIA_TYPE_AUDIO, |
| 309 | .id = AV_CODEC_ID_PCM_DVD, |
| 310 | .priv_data_size = sizeof(PCMDVDContext), |
| 311 | .init = pcm_dvd_decode_init, |
| 312 | .decode = pcm_dvd_decode_frame, |
| 313 | .close = pcm_dvd_decode_uninit, |
| 314 | .capabilities = CODEC_CAP_DR1, |
| 315 | .sample_fmts = (const enum AVSampleFormat[]) { |
| 316 | AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE |
| 317 | } |
| 318 | }; |