ffmpeg/libavcodec/pcm-dvd.c

   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
 162     bytestream2_init(&gb, src, blocks * s->block_size);
 163     switch (avctx->bits_per_coded_sample) {
 164     case 16: {
 165 #if HAVE_BIGENDIAN
 166         bytestream2_get_buffer(&gb, dst16, blocks * s->block_size);
 167         dst16 += blocks * s->block_size / 2;
 168 #else
 169         int samples = blocks * avctx->channels;
 170         do {
 171             *dst16++ = bytestream2_get_be16u(&gb);
 172         } while (--samples);
 173 #endif
 174         return dst16;
 175     }
 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 };