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