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FFmpeg/libavcodec/pcm-mpeg.c

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  1. /*

  2.  * LPCM codecs for PCM formats found in MPEG streams

  3.  * Copyright (c) 2009 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.  * PCM codecs for encodings found in MPEG streams (DVD/Blu-ray)

  25.  */

  26. 

  27. #include "libavutil/channel_layout.h"

  28. #include "avcodec.h"

  29. #include "bytestream.h"

  30. #include "internal.h"

  31. 

  32. /*

  33.  * Channel Mapping according to

  34.  * Blu-ray Disc Read-Only Format Version 1

  35.  * Part 3: Audio Visual Basic Specifications

  36.  * mono     M1    X

  37.  * stereo   L     R

  38.  * 3/0      L     R    C    X

  39.  * 2/1      L     R    S    X

  40.  * 3/1      L     R    C    S

  41.  * 2/2      L     R    LS   RS

  42.  * 3/2      L     R    C    LS    RS    X

  43.  * 3/2+lfe  L     R    C    LS    RS    lfe

  44.  * 3/4      L     R    C    LS    Rls   Rrs  RS   X

  45.  * 3/4+lfe  L     R    C    LS    Rls   Rrs  RS   lfe

  46.  */

  47. 

  48. /**

  49.  * Parse the header of a LPCM frame read from a MPEG-TS stream

  50.  * @param avctx the codec context

  51.  * @param header pointer to the first four bytes of the data packet

  52.  */

  53. static int pcm_bluray_parse_header(AVCodecContext *avctx,

  54.                                    const uint8_t *header)

  55. {

  56.     static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };

  57.     static const uint32_t channel_layouts[16] = {

  58.         0, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,

  59.         AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,

  60.         AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_CH_LAYOUT_7POINT1, 0, 0, 0, 0

  61.     };

  62.     static const uint8_t channels[16] = {

  63.         0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0

  64.     };

  65.     uint8_t channel_layout = header[2] >> 4;

  66. 

  67.     if (avctx->debug & FF_DEBUG_PICT_INFO)

  68.         av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",

  69.                 header[0], header[1], header[2], header[3]);

  70. 

  71.     /* get the sample depth and derive the sample format from it */

  72.     avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];

  73.     if (!(avctx->bits_per_coded_sample == 16 || avctx->bits_per_coded_sample == 24)) {

  74.         av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (%d)\n", avctx->bits_per_coded_sample);

  75.         return -1;

  76.     }

  77.     avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :

  78.                                                              AV_SAMPLE_FMT_S32;

  79.     if (avctx->sample_fmt == AV_SAMPLE_FMT_S32)

  80.         avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;

  81. 

  82.     /* get the sample rate. Not all values are used. */

  83.     switch (header[2] & 0x0f) {

  84.     case 1:

  85.         avctx->sample_rate = 48000;

  86.         break;

  87.     case 4:

  88.         avctx->sample_rate = 96000;

  89.         break;

  90.     case 5:

  91.         avctx->sample_rate = 192000;

  92.         break;

  93.     default:

  94.         avctx->sample_rate = 0;

  95.         av_log(avctx, AV_LOG_ERROR, "reserved sample rate (%d)\n",

  96.                header[2] & 0x0f);

  97.         return -1;

  98.     }

  99. 

  100.     /*

  101.      * get the channel number (and mapping). Not all values are used.

  102.      * It must be noted that the number of channels in the MPEG stream can

  103.      * differ from the actual meaningful number, e.g. mono audio still has two

  104.      * channels, one being empty.

  105.      */

  106.     avctx->channel_layout  = channel_layouts[channel_layout];

  107.     avctx->channels        =        channels[channel_layout];

  108.     if (!avctx->channels) {

  109.         av_log(avctx, AV_LOG_ERROR, "reserved channel configuration (%d)\n",

  110.                channel_layout);

  111.         return -1;

  112.     }

  113. 

  114.     avctx->bit_rate = FFALIGN(avctx->channels, 2) * avctx->sample_rate *

  115.                       avctx->bits_per_coded_sample;

  116. 

  117.     if (avctx->debug & FF_DEBUG_PICT_INFO)

  118.         av_dlog(avctx,

  119.                 "pcm_bluray_parse_header: %d channels, %d bits per sample, %d Hz, %d bit/s\n",

  120.                 avctx->channels, avctx->bits_per_coded_sample,

  121.                 avctx->sample_rate, avctx->bit_rate);

  122.     return 0;

  123. }

  124. 

  125. static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,

  126.                                    int *got_frame_ptr, AVPacket *avpkt)

  127. {

  128.     AVFrame *frame     = data;

  129.     const uint8_t *src = avpkt->data;

  130.     int buf_size = avpkt->size;

  131.     GetByteContext gb;

  132.     int num_source_channels, channel, retval;

  133.     int sample_size, samples;

  134.     int16_t *dst16;

  135.     int32_t *dst32;

  136. 

  137.     if (buf_size < 4) {

  138.         av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");

  139.         return -1;

  140.     }

  141. 

  142.     if (pcm_bluray_parse_header(avctx, src))

  143.         return -1;

  144.     src += 4;

  145.     buf_size -= 4;

  146. 

  147.     bytestream2_init(&gb, src, buf_size);

  148. 

  149.     /* There's always an even number of channels in the source */

  150.     num_source_channels = FFALIGN(avctx->channels, 2);

  151.     sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;

  152.     samples = buf_size / sample_size;

  153. 

  154.     /* get output buffer */

  155.     frame->nb_samples = samples;

  156.     if ((retval = ff_get_buffer(avctx, frame, 0)) < 0)

  157.         return retval;

  158.     dst16 = (int16_t *)frame->data[0];

  159.     dst32 = (int32_t *)frame->data[0];

  160. 

  161.     if (samples) {

  162.         switch (avctx->channel_layout) {

  163.             /* cases with same number of source and coded channels */

  164.         case AV_CH_LAYOUT_STEREO:

  165.         case AV_CH_LAYOUT_4POINT0:

  166.         case AV_CH_LAYOUT_2_2:

  167.             samples *= num_source_channels;

  168.             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {

  169. #if HAVE_BIGENDIAN

  170.                 bytestream2_get_buffer(&gb, dst16, buf_size);

  171. #else

  172.                 do {

  173.                     *dst16++ = bytestream2_get_be16u(&gb);

  174.                 } while (--samples);

  175. #endif

  176.             } else {

  177.                 do {

  178.                     *dst32++ = bytestream2_get_be24u(&gb) << 8;

  179.                 } while (--samples);

  180.             }

  181.             break;

  182.         /* cases where number of source channels = coded channels + 1 */

  183.         case AV_CH_LAYOUT_MONO:

  184.         case AV_CH_LAYOUT_SURROUND:

  185.         case AV_CH_LAYOUT_2_1:

  186.         case AV_CH_LAYOUT_5POINT0:

  187.             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {

  188.                 do {

  189. #if HAVE_BIGENDIAN

  190.                     bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);

  191.                     dst16 += avctx->channels;

  192. #else

  193.                     channel = avctx->channels;

  194.                     do {

  195.                         *dst16++ = bytestream2_get_be16u(&gb);

  196.                     } while (--channel);

  197. #endif

  198.                     bytestream2_skip(&gb, 2);

  199.                 } while (--samples);

  200.             } else {

  201.                 do {

  202.                     channel = avctx->channels;

  203.                     do {

  204.                         *dst32++ = bytestream2_get_be24u(&gb) << 8;

  205.                     } while (--channel);

  206.                     bytestream2_skip(&gb, 3);

  207.                 } while (--samples);

  208.             }

  209.             break;

  210.             /* remapping: L, R, C, LBack, RBack, LF */

  211.         case AV_CH_LAYOUT_5POINT1:

  212.             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {

  213.                 do {

  214.                     dst16[0] = bytestream2_get_be16u(&gb);

  215.                     dst16[1] = bytestream2_get_be16u(&gb);

  216.                     dst16[2] = bytestream2_get_be16u(&gb);

  217.                     dst16[4] = bytestream2_get_be16u(&gb);

  218.                     dst16[5] = bytestream2_get_be16u(&gb);

  219.                     dst16[3] = bytestream2_get_be16u(&gb);

  220.                     dst16 += 6;

  221.                 } while (--samples);

  222.             } else {

  223.                 do {

  224.                     dst32[0] = bytestream2_get_be24u(&gb) << 8;

  225.                     dst32[1] = bytestream2_get_be24u(&gb) << 8;

  226.                     dst32[2] = bytestream2_get_be24u(&gb) << 8;

  227.                     dst32[4] = bytestream2_get_be24u(&gb) << 8;

  228.                     dst32[5] = bytestream2_get_be24u(&gb) << 8;

  229.                     dst32[3] = bytestream2_get_be24u(&gb) << 8;

  230.                     dst32 += 6;

  231.                 } while (--samples);

  232.             }

  233.             break;

  234.             /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */

  235.         case AV_CH_LAYOUT_7POINT0:

  236.             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {

  237.                 do {

  238.                     dst16[0] = bytestream2_get_be16u(&gb);

  239.                     dst16[1] = bytestream2_get_be16u(&gb);

  240.                     dst16[2] = bytestream2_get_be16u(&gb);

  241.                     dst16[5] = bytestream2_get_be16u(&gb);

  242.                     dst16[3] = bytestream2_get_be16u(&gb);

  243.                     dst16[4] = bytestream2_get_be16u(&gb);

  244.                     dst16[6] = bytestream2_get_be16u(&gb);

  245.                     dst16 += 7;

  246.                     bytestream2_skip(&gb, 2);

  247.                 } while (--samples);

  248.             } else {

  249.                 do {

  250.                     dst32[0] = bytestream2_get_be24u(&gb) << 8;

  251.                     dst32[1] = bytestream2_get_be24u(&gb) << 8;

  252.                     dst32[2] = bytestream2_get_be24u(&gb) << 8;

  253.                     dst32[5] = bytestream2_get_be24u(&gb) << 8;

  254.                     dst32[3] = bytestream2_get_be24u(&gb) << 8;

  255.                     dst32[4] = bytestream2_get_be24u(&gb) << 8;

  256.                     dst32[6] = bytestream2_get_be24u(&gb) << 8;

  257.                     dst32 += 7;

  258.                     bytestream2_skip(&gb, 3);

  259.                 } while (--samples);

  260.             }

  261.             break;

  262.             /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */

  263.         case AV_CH_LAYOUT_7POINT1:

  264.             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {

  265.                 do {

  266.                     dst16[0] = bytestream2_get_be16u(&gb);

  267.                     dst16[1] = bytestream2_get_be16u(&gb);

  268.                     dst16[2] = bytestream2_get_be16u(&gb);

  269.                     dst16[6] = bytestream2_get_be16u(&gb);

  270.                     dst16[4] = bytestream2_get_be16u(&gb);

  271.                     dst16[5] = bytestream2_get_be16u(&gb);

  272.                     dst16[7] = bytestream2_get_be16u(&gb);

  273.                     dst16[3] = bytestream2_get_be16u(&gb);

  274.                     dst16 += 8;

  275.                 } while (--samples);

  276.             } else {

  277.                 do {

  278.                     dst32[0] = bytestream2_get_be24u(&gb) << 8;

  279.                     dst32[1] = bytestream2_get_be24u(&gb) << 8;

  280.                     dst32[2] = bytestream2_get_be24u(&gb) << 8;

  281.                     dst32[6] = bytestream2_get_be24u(&gb) << 8;

  282.                     dst32[4] = bytestream2_get_be24u(&gb) << 8;

  283.                     dst32[5] = bytestream2_get_be24u(&gb) << 8;

  284.                     dst32[7] = bytestream2_get_be24u(&gb) << 8;

  285.                     dst32[3] = bytestream2_get_be24u(&gb) << 8;

  286.                     dst32 += 8;

  287.                 } while (--samples);

  288.             }

  289.             break;

  290.         }

  291.     }

  292. 

  293.     *got_frame_ptr = 1;

  294. 

  295.     retval = bytestream2_tell(&gb);

  296.     if (avctx->debug & FF_DEBUG_BITSTREAM)

  297.         av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",

  298.                 retval, buf_size);

  299.     return retval + 4;

  300. }

  301. 

  302. AVCodec ff_pcm_bluray_decoder = {

  303.     .name           = "pcm_bluray",

  304.     .type           = AVMEDIA_TYPE_AUDIO,

  305.     .id             = AV_CODEC_ID_PCM_BLURAY,

  306.     .decode         = pcm_bluray_decode_frame,

  307.     .capabilities   = CODEC_CAP_DR1,

  308.     .sample_fmts    = (const enum AVSampleFormat[]){

  309.         AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE

  310.     },

  311.     .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),

  312. };