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 "codec_internal.h" 30#include "internal.h" 31 32typedef struct PCMDVDContext { 33 uint32_t last_header; // Cached header to see if parsing is needed 34 int block_size; // Size of a block of samples in bytes 35 int last_block_size; // Size of the last block of samples in bytes 36 int samples_per_block; // Number of samples per channel per block 37 int groups_per_block; // Number of 20/24-bit sample groups per block 38 int extra_sample_count; // Number of leftover samples in the buffer 39 uint8_t extra_samples[8 * 3 * 4]; // Space for leftover samples from a frame 40 // (8 channels, 3B/sample, 4 samples/block) 41} PCMDVDContext; 42 43static av_cold int pcm_dvd_decode_init(AVCodecContext *avctx) 44{ 45 PCMDVDContext *s = avctx->priv_data; 46 47 /* Invalid header to force parsing of the first header */ 48 s->last_header = -1; 49 50 return 0; 51} 52 53static int pcm_dvd_parse_header(AVCodecContext *avctx, const uint8_t *header) 54{ 55 /* no traces of 44100 and 32000Hz in any commercial software or player */ 56 static const uint32_t frequencies[4] = { 48000, 96000, 44100, 32000 }; 57 PCMDVDContext *s = avctx->priv_data; 58 int header_int = (header[0] & 0xe0) | (header[1] << 8) | (header[2] << 16); 59 int channels; 60 61 /* early exit if the header didn't change apart from the frame number */ 62 if (s->last_header == header_int) 63 return 0; 64 s->last_header = -1; 65 66 if (avctx->debug & FF_DEBUG_PICT_INFO) 67 av_log(avctx, AV_LOG_DEBUG, "pcm_dvd_parse_header: header = %02x%02x%02x\n", 68 header[0], header[1], header[2]); 69 /* 70 * header[0] emphasis (1), muse(1), reserved(1), frame number(5) 71 * header[1] quant (2), freq(2), reserved(1), channels(3) 72 * header[2] dynamic range control (0x80 = off) 73 */ 74 75 /* Discard potentially existing leftover samples from old channel layout */ 76 s->extra_sample_count = 0; 77 78 /* get the sample depth and derive the sample format from it */ 79 avctx->bits_per_coded_sample = 16 + (header[1] >> 6 & 3) * 4; 80 if (avctx->bits_per_coded_sample == 28) { 81 av_log(avctx, AV_LOG_ERROR, 82 "PCM DVD unsupported sample depth %i\n", 83 avctx->bits_per_coded_sample); 84 return AVERROR_INVALIDDATA; 85 } 86 avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 87 : AV_SAMPLE_FMT_S32; 88 avctx->bits_per_raw_sample = avctx->bits_per_coded_sample; 89 90 /* get the sample rate */ 91 avctx->sample_rate = frequencies[header[1] >> 4 & 3]; 92 93 /* get the number of channels */ 94 channels = 1 + (header[1] & 7); 95 96 av_channel_layout_uninit(&avctx->ch_layout); 97 av_channel_layout_default(&avctx->ch_layout, channels); 98 /* calculate the bitrate */ 99 avctx->bit_rate = channels * 100 avctx->sample_rate * 101 avctx->bits_per_coded_sample; 102 103 /* 4 samples form a group in 20/24-bit PCM on DVD Video. 104 * A block is formed by the number of groups that are 105 * needed to complete a set of samples for each channel. */ 106 if (avctx->bits_per_coded_sample == 16) { 107 s->samples_per_block = 1; 108 s->block_size = channels * 2; 109 } else { 110 switch (channels) { 111 case 1: 112 case 2: 113 case 4: 114 /* one group has all the samples needed */ 115 s->block_size = 4 * avctx->bits_per_coded_sample / 8; 116 s->samples_per_block = 4 / channels; 117 s->groups_per_block = 1; 118 break; 119 case 8: 120 /* two groups have all the samples needed */ 121 s->block_size = 8 * avctx->bits_per_coded_sample / 8; 122 s->samples_per_block = 1; 123 s->groups_per_block = 2; 124 break; 125 default: 126 /* need channels groups */ 127 s->block_size = 4 * channels * 128 avctx->bits_per_coded_sample / 8; 129 s->samples_per_block = 4; 130 s->groups_per_block = channels; 131 break; 132 } 133 } 134 135 if (avctx->debug & FF_DEBUG_PICT_INFO) 136 ff_dlog(avctx, 137 "pcm_dvd_parse_header: %d channels, %d bits per sample, %d Hz, %"PRId64" bit/s\n", 138 avctx->ch_layout.nb_channels, avctx->bits_per_coded_sample, 139 avctx->sample_rate, avctx->bit_rate); 140 141 s->last_header = header_int; 142 143 return 0; 144} 145 146static void *pcm_dvd_decode_samples(AVCodecContext *avctx, const uint8_t *src, 147 void *dst, int blocks) 148{ 149 PCMDVDContext *s = avctx->priv_data; 150 int16_t *dst16 = dst; 151 int32_t *dst32 = dst; 152 GetByteContext gb; 153 int i; 154 uint8_t t; 155 156 bytestream2_init(&gb, src, blocks * s->block_size); 157 switch (avctx->bits_per_coded_sample) { 158 case 16: { 159#if HAVE_BIGENDIAN 160 bytestream2_get_buffer(&gb, dst16, blocks * s->block_size); 161 dst16 += blocks * s->block_size / 2; 162#else 163 int samples = blocks * avctx->ch_layout.nb_channels; 164 do { 165 *dst16++ = bytestream2_get_be16u(&gb); 166 } while (--samples); 167#endif 168 return dst16; 169 } 170 case 20: 171 if (avctx->ch_layout.nb_channels == 1) { 172 do { 173 for (i = 2; i; i--) { 174 dst32[0] = bytestream2_get_be16u(&gb) << 16; 175 dst32[1] = bytestream2_get_be16u(&gb) << 16; 176 t = bytestream2_get_byteu(&gb); 177 *dst32++ += (t & 0xf0) << 8; 178 *dst32++ += (t & 0x0f) << 12; 179 } 180 } while (--blocks); 181 } else { 182 do { 183 for (i = s->groups_per_block; i; i--) { 184 dst32[0] = bytestream2_get_be16u(&gb) << 16; 185 dst32[1] = bytestream2_get_be16u(&gb) << 16; 186 dst32[2] = bytestream2_get_be16u(&gb) << 16; 187 dst32[3] = bytestream2_get_be16u(&gb) << 16; 188 t = bytestream2_get_byteu(&gb); 189 *dst32++ += (t & 0xf0) << 8; 190 *dst32++ += (t & 0x0f) << 12; 191 t = bytestream2_get_byteu(&gb); 192 *dst32++ += (t & 0xf0) << 8; 193 *dst32++ += (t & 0x0f) << 12; 194 } 195 } while (--blocks); 196 } 197 return dst32; 198 case 24: 199 if (avctx->ch_layout.nb_channels == 1) { 200 do { 201 for (i = 2; i; i--) { 202 dst32[0] = bytestream2_get_be16u(&gb) << 16; 203 dst32[1] = bytestream2_get_be16u(&gb) << 16; 204 *dst32++ += bytestream2_get_byteu(&gb) << 8; 205 *dst32++ += bytestream2_get_byteu(&gb) << 8; 206 } 207 } while (--blocks); 208 } else { 209 do { 210 for (i = s->groups_per_block; i; i--) { 211 dst32[0] = bytestream2_get_be16u(&gb) << 16; 212 dst32[1] = bytestream2_get_be16u(&gb) << 16; 213 dst32[2] = bytestream2_get_be16u(&gb) << 16; 214 dst32[3] = bytestream2_get_be16u(&gb) << 16; 215 *dst32++ += bytestream2_get_byteu(&gb) << 8; 216 *dst32++ += bytestream2_get_byteu(&gb) << 8; 217 *dst32++ += bytestream2_get_byteu(&gb) << 8; 218 *dst32++ += bytestream2_get_byteu(&gb) << 8; 219 } 220 } while (--blocks); 221 } 222 return dst32; 223 default: 224 return NULL; 225 } 226} 227 228static int pcm_dvd_decode_frame(AVCodecContext *avctx, AVFrame *frame, 229 int *got_frame_ptr, AVPacket *avpkt) 230{ 231 const uint8_t *src = avpkt->data; 232 int buf_size = avpkt->size; 233 PCMDVDContext *s = avctx->priv_data; 234 int retval; 235 int blocks; 236 void *dst; 237 238 if (buf_size < 3) { 239 av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n"); 240 return AVERROR_INVALIDDATA; 241 } 242 243 if ((retval = pcm_dvd_parse_header(avctx, src))) 244 return retval; 245 if (s->last_block_size && s->last_block_size != s->block_size) { 246 av_log(avctx, AV_LOG_WARNING, "block_size has changed %d != %d\n", s->last_block_size, s->block_size); 247 s->extra_sample_count = 0; 248 } 249 s->last_block_size = s->block_size; 250 src += 3; 251 buf_size -= 3; 252 253 blocks = (buf_size + s->extra_sample_count) / s->block_size; 254 255 /* get output buffer */ 256 frame->nb_samples = blocks * s->samples_per_block; 257 if ((retval = ff_get_buffer(avctx, frame, 0)) < 0) 258 return retval; 259 dst = frame->data[0]; 260 261 /* consume leftover samples from last packet */ 262 if (s->extra_sample_count) { 263 int missing_samples = s->block_size - s->extra_sample_count; 264 if (buf_size >= missing_samples) { 265 memcpy(s->extra_samples + s->extra_sample_count, src, 266 missing_samples); 267 dst = pcm_dvd_decode_samples(avctx, s->extra_samples, dst, 1); 268 src += missing_samples; 269 buf_size -= missing_samples; 270 s->extra_sample_count = 0; 271 blocks--; 272 } else { 273 /* new packet still doesn't have enough samples */ 274 memcpy(s->extra_samples + s->extra_sample_count, src, buf_size); 275 s->extra_sample_count += buf_size; 276 return avpkt->size; 277 } 278 } 279 280 /* decode remaining complete samples */ 281 if (blocks) { 282 pcm_dvd_decode_samples(avctx, src, dst, blocks); 283 buf_size -= blocks * s->block_size; 284 } 285 286 /* store leftover samples */ 287 if (buf_size) { 288 src += blocks * s->block_size; 289 memcpy(s->extra_samples, src, buf_size); 290 s->extra_sample_count = buf_size; 291 } 292 293 *got_frame_ptr = 1; 294 295 return avpkt->size; 296} 297 298const FFCodec ff_pcm_dvd_decoder = { 299 .p.name = "pcm_dvd", 300 .p.long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for DVD media"), 301 .p.type = AVMEDIA_TYPE_AUDIO, 302 .p.id = AV_CODEC_ID_PCM_DVD, 303 .priv_data_size = sizeof(PCMDVDContext), 304 .init = pcm_dvd_decode_init, 305 FF_CODEC_DECODE_CB(pcm_dvd_decode_frame), 306 .p.capabilities = AV_CODEC_CAP_CHANNEL_CONF | 307 AV_CODEC_CAP_DR1, 308 .p.sample_fmts = (const enum AVSampleFormat[]) { 309 AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE 310 }, 311 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE, 312}; 313