FFmpeg: libavcodec/pcm-mpeg.c Source File

00001 /*
00002  * LPCM codecs for PCM formats found in MPEG streams
00003  * Copyright (c) 2009 Christian Schmidt
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #include "libavutil/channel_layout.h"
00028 #include "avcodec.h"
00029 #include "bytestream.h"
00030 #include "internal.h"
00031 
00032 /*
00033  * Channel Mapping according to
00034  * Blu-ray Disc Read-Only Format Version 1
00035  * Part 3: Audio Visual Basic Specifications
00036  * mono     M1    X
00037  * stereo   L     R
00038  * 3/0      L     R    C    X
00039  * 2/1      L     R    S    X
00040  * 3/1      L     R    C    S
00041  * 2/2      L     R    LS   RS
00042  * 3/2      L     R    C    LS    RS    X
00043  * 3/2+lfe  L     R    C    LS    RS    lfe
00044  * 3/4      L     R    C    LS    Rls   Rrs  RS   X
00045  * 3/4+lfe  L     R    C    LS    Rls   Rrs  RS   lfe
00046  */
00047 
00053 static int pcm_bluray_parse_header(AVCodecContext *avctx,
00054                                    const uint8_t *header)
00055 {
00056     static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
00057     static const uint32_t channel_layouts[16] = {
00058         0, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,
00059         AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,
00060         AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_CH_LAYOUT_7POINT1, 0, 0, 0, 0
00061     };
00062     static const uint8_t channels[16] = {
00063         0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
00064     };
00065     uint8_t channel_layout = header[2] >> 4;
00066 
00067     if (avctx->debug & FF_DEBUG_PICT_INFO)
00068         av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
00069                 header[0], header[1], header[2], header[3]);
00070 
00071     /* get the sample depth and derive the sample format from it */
00072     avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
00073     if (!(avctx->bits_per_coded_sample == 16 || avctx->bits_per_coded_sample == 24)) {
00074         av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (%d)\n", avctx->bits_per_coded_sample);
00075         return -1;
00076     }
00077     avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
00078                                                              AV_SAMPLE_FMT_S32;
00079     if (avctx->sample_fmt == AV_SAMPLE_FMT_S32)
00080         avctx->bits_per_raw_sample = avctx->bits_per_coded_sample;
00081 
00082     /* get the sample rate. Not all values are used. */
00083     switch (header[2] & 0x0f) {
00084     case 1:
00085         avctx->sample_rate = 48000;
00086         break;
00087     case 4:
00088         avctx->sample_rate = 96000;
00089         break;
00090     case 5:
00091         avctx->sample_rate = 192000;
00092         break;
00093     default:
00094         avctx->sample_rate = 0;
00095         av_log(avctx, AV_LOG_ERROR, "reserved sample rate (%d)\n",
00096                header[2] & 0x0f);
00097         return -1;
00098     }
00099 
00100     /*
00101      * get the channel number (and mapping). Not all values are used.
00102      * It must be noted that the number of channels in the MPEG stream can
00103      * differ from the actual meaningful number, e.g. mono audio still has two
00104      * channels, one being empty.
00105      */
00106     avctx->channel_layout  = channel_layouts[channel_layout];
00107     avctx->channels        =        channels[channel_layout];
00108     if (!avctx->channels) {
00109         av_log(avctx, AV_LOG_ERROR, "reserved channel configuration (%d)\n",
00110                channel_layout);
00111         return -1;
00112     }
00113 
00114     avctx->bit_rate = FFALIGN(avctx->channels, 2) * avctx->sample_rate *
00115                       avctx->bits_per_coded_sample;
00116 
00117     if (avctx->debug & FF_DEBUG_PICT_INFO)
00118         av_dlog(avctx,
00119                 "pcm_bluray_parse_header: %d channels, %d bits per sample, %d Hz, %d bit/s\n",
00120                 avctx->channels, avctx->bits_per_coded_sample,
00121                 avctx->sample_rate, avctx->bit_rate);
00122     return 0;
00123 }
00124 
00125 typedef struct PCMBRDecode {
00126     AVFrame frame;
00127 } PCMBRDecode;
00128 
00129 static av_cold int pcm_bluray_decode_init(AVCodecContext * avctx)
00130 {
00131     PCMBRDecode *s = avctx->priv_data;
00132 
00133     avcodec_get_frame_defaults(&s->frame);
00134     avctx->coded_frame = &s->frame;
00135 
00136     return 0;
00137 }
00138 
00139 static int pcm_bluray_decode_frame(AVCodecContext *avctx, void *data,
00140                                    int *got_frame_ptr, AVPacket *avpkt)
00141 {
00142     const uint8_t *src = avpkt->data;
00143     int buf_size = avpkt->size;
00144     PCMBRDecode *s = avctx->priv_data;
00145     GetByteContext gb;
00146     int num_source_channels, channel, retval;
00147     int sample_size, samples;
00148     int16_t *dst16;
00149     int32_t *dst32;
00150 
00151     if (buf_size < 4) {
00152         av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
00153         return -1;
00154     }
00155 
00156     if (pcm_bluray_parse_header(avctx, src))
00157         return -1;
00158     src += 4;
00159     buf_size -= 4;
00160 
00161     bytestream2_init(&gb, src, buf_size);
00162 
00163     /* There's always an even number of channels in the source */
00164     num_source_channels = FFALIGN(avctx->channels, 2);
00165     sample_size = (num_source_channels * (avctx->sample_fmt == AV_SAMPLE_FMT_S16 ? 16 : 24)) >> 3;
00166     samples = buf_size / sample_size;
00167 
00168     /* get output buffer */
00169     s->frame.nb_samples = samples;
00170     if ((retval = ff_get_buffer(avctx, &s->frame)) < 0) {
00171         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00172         return retval;
00173     }
00174     dst16 = (int16_t *)s->frame.data[0];
00175     dst32 = (int32_t *)s->frame.data[0];
00176 
00177     if (samples) {
00178         switch (avctx->channel_layout) {
00179             /* cases with same number of source and coded channels */
00180         case AV_CH_LAYOUT_STEREO:
00181         case AV_CH_LAYOUT_4POINT0:
00182         case AV_CH_LAYOUT_2_2:
00183             samples *= num_source_channels;
00184             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00185 #if HAVE_BIGENDIAN
00186                 bytestream2_get_buffer(&gb, dst16, buf_size);
00187 #else
00188                 do {
00189                     *dst16++ = bytestream2_get_be16u(&gb);
00190                 } while (--samples);
00191 #endif
00192             } else {
00193                 do {
00194                     *dst32++ = bytestream2_get_be24u(&gb) << 8;
00195                 } while (--samples);
00196             }
00197             break;
00198         /* cases where number of source channels = coded channels + 1 */
00199         case AV_CH_LAYOUT_MONO:
00200         case AV_CH_LAYOUT_SURROUND:
00201         case AV_CH_LAYOUT_2_1:
00202         case AV_CH_LAYOUT_5POINT0:
00203             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00204                 do {
00205 #if HAVE_BIGENDIAN
00206                     bytestream2_get_buffer(&gb, dst16, avctx->channels * 2);
00207                     dst16 += avctx->channels;
00208 #else
00209                     channel = avctx->channels;
00210                     do {
00211                         *dst16++ = bytestream2_get_be16u(&gb);
00212                     } while (--channel);
00213 #endif
00214                     bytestream2_skip(&gb, 2);
00215                 } while (--samples);
00216             } else {
00217                 do {
00218                     channel = avctx->channels;
00219                     do {
00220                         *dst32++ = bytestream2_get_be24u(&gb) << 8;
00221                     } while (--channel);
00222                     bytestream2_skip(&gb, 3);
00223                 } while (--samples);
00224             }
00225             break;
00226             /* remapping: L, R, C, LBack, RBack, LF */
00227         case AV_CH_LAYOUT_5POINT1:
00228             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00229                 do {
00230                     dst16[0] = bytestream2_get_be16u(&gb);
00231                     dst16[1] = bytestream2_get_be16u(&gb);
00232                     dst16[2] = bytestream2_get_be16u(&gb);
00233                     dst16[4] = bytestream2_get_be16u(&gb);
00234                     dst16[5] = bytestream2_get_be16u(&gb);
00235                     dst16[3] = bytestream2_get_be16u(&gb);
00236                     dst16 += 6;
00237                 } while (--samples);
00238             } else {
00239                 do {
00240                     dst32[0] = bytestream2_get_be24u(&gb) << 8;
00241                     dst32[1] = bytestream2_get_be24u(&gb) << 8;
00242                     dst32[2] = bytestream2_get_be24u(&gb) << 8;
00243                     dst32[4] = bytestream2_get_be24u(&gb) << 8;
00244                     dst32[5] = bytestream2_get_be24u(&gb) << 8;
00245                     dst32[3] = bytestream2_get_be24u(&gb) << 8;
00246                     dst32 += 6;
00247                 } while (--samples);
00248             }
00249             break;
00250             /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
00251         case AV_CH_LAYOUT_7POINT0:
00252             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00253                 do {
00254                     dst16[0] = bytestream2_get_be16u(&gb);
00255                     dst16[1] = bytestream2_get_be16u(&gb);
00256                     dst16[2] = bytestream2_get_be16u(&gb);
00257                     dst16[5] = bytestream2_get_be16u(&gb);
00258                     dst16[3] = bytestream2_get_be16u(&gb);
00259                     dst16[4] = bytestream2_get_be16u(&gb);
00260                     dst16[6] = bytestream2_get_be16u(&gb);
00261                     dst16 += 7;
00262                     bytestream2_skip(&gb, 2);
00263                 } while (--samples);
00264             } else {
00265                 do {
00266                     dst32[0] = bytestream2_get_be24u(&gb) << 8;
00267                     dst32[1] = bytestream2_get_be24u(&gb) << 8;
00268                     dst32[2] = bytestream2_get_be24u(&gb) << 8;
00269                     dst32[5] = bytestream2_get_be24u(&gb) << 8;
00270                     dst32[3] = bytestream2_get_be24u(&gb) << 8;
00271                     dst32[4] = bytestream2_get_be24u(&gb) << 8;
00272                     dst32[6] = bytestream2_get_be24u(&gb) << 8;
00273                     dst32 += 7;
00274                     bytestream2_skip(&gb, 3);
00275                 } while (--samples);
00276             }
00277             break;
00278             /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
00279         case AV_CH_LAYOUT_7POINT1:
00280             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00281                 do {
00282                     dst16[0] = bytestream2_get_be16u(&gb);
00283                     dst16[1] = bytestream2_get_be16u(&gb);
00284                     dst16[2] = bytestream2_get_be16u(&gb);
00285                     dst16[6] = bytestream2_get_be16u(&gb);
00286                     dst16[4] = bytestream2_get_be16u(&gb);
00287                     dst16[5] = bytestream2_get_be16u(&gb);
00288                     dst16[7] = bytestream2_get_be16u(&gb);
00289                     dst16[3] = bytestream2_get_be16u(&gb);
00290                     dst16 += 8;
00291                 } while (--samples);
00292             } else {
00293                 do {
00294                     dst32[0] = bytestream2_get_be24u(&gb) << 8;
00295                     dst32[1] = bytestream2_get_be24u(&gb) << 8;
00296                     dst32[2] = bytestream2_get_be24u(&gb) << 8;
00297                     dst32[6] = bytestream2_get_be24u(&gb) << 8;
00298                     dst32[4] = bytestream2_get_be24u(&gb) << 8;
00299                     dst32[5] = bytestream2_get_be24u(&gb) << 8;
00300                     dst32[7] = bytestream2_get_be24u(&gb) << 8;
00301                     dst32[3] = bytestream2_get_be24u(&gb) << 8;
00302                     dst32 += 8;
00303                 } while (--samples);
00304             }
00305             break;
00306         }
00307     }
00308 
00309     *got_frame_ptr   = 1;
00310     *(AVFrame *)data = s->frame;
00311 
00312     retval = bytestream2_tell(&gb);
00313     if (avctx->debug & FF_DEBUG_BITSTREAM)
00314         av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
00315                 retval, buf_size);
00316     return retval + 4;
00317 }
00318 
00319 AVCodec ff_pcm_bluray_decoder = {
00320     .name           = "pcm_bluray",
00321     .type           = AVMEDIA_TYPE_AUDIO,
00322     .id             = AV_CODEC_ID_PCM_BLURAY,
00323     .priv_data_size = sizeof(PCMBRDecode),
00324     .init           = pcm_bluray_decode_init,
00325     .decode         = pcm_bluray_decode_frame,
00326     .capabilities   = CODEC_CAP_DR1,
00327     .sample_fmts    = (const enum AVSampleFormat[]){
00328         AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_NONE
00329     },
00330     .long_name      = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
00331 };