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/audioconvert.h"
00028 #include "avcodec.h"
00029 #include "bytestream.h"
00030 
00031 /*
00032  * Channel Mapping according to
00033  * Blu-ray Disc Read-Only Format Version 1
00034  * Part 3: Audio Visual Basic Specifications
00035  * mono     M1    X
00036  * stereo   L     R
00037  * 3/0      L     R    C    X
00038  * 2/1      L     R    S    X
00039  * 3/1      L     R    C    S
00040  * 2/2      L     R    LS   RS
00041  * 3/2      L     R    C    LS    RS    X
00042  * 3/2+lfe  L     R    C    LS    RS    lfe
00043  * 3/4      L     R    C    LS    Rls   Rrs  RS   X
00044  * 3/4+lfe  L     R    C    LS    Rls   Rrs  RS   lfe
00045  */
00046 
00052 static int pcm_bluray_parse_header(AVCodecContext *avctx,
00053                                    const uint8_t *header)
00054 {
00055     static const uint8_t bits_per_samples[4] = { 0, 16, 20, 24 };
00056     static const uint32_t channel_layouts[16] = {
00057         0, AV_CH_LAYOUT_MONO, 0, AV_CH_LAYOUT_STEREO, AV_CH_LAYOUT_SURROUND,
00058         AV_CH_LAYOUT_2_1, AV_CH_LAYOUT_4POINT0, AV_CH_LAYOUT_2_2, AV_CH_LAYOUT_5POINT0,
00059         AV_CH_LAYOUT_5POINT1, AV_CH_LAYOUT_7POINT0, AV_CH_LAYOUT_7POINT1, 0, 0, 0, 0
00060     };
00061     static const uint8_t channels[16] = {
00062         0, 1, 0, 2, 3, 3, 4, 4, 5, 6, 7, 8, 0, 0, 0, 0
00063     };
00064     uint8_t channel_layout = header[2] >> 4;
00065 
00066     if (avctx->debug & FF_DEBUG_PICT_INFO)
00067         av_dlog(avctx, "pcm_bluray_parse_header: header = %02x%02x%02x%02x\n",
00068                 header[0], header[1], header[2], header[3]);
00069 
00070     /* get the sample depth and derive the sample format from it */
00071     avctx->bits_per_coded_sample = bits_per_samples[header[3] >> 6];
00072     if (!avctx->bits_per_coded_sample) {
00073         av_log(avctx, AV_LOG_ERROR, "unsupported sample depth (0)\n");
00074         return -1;
00075     }
00076     avctx->sample_fmt = avctx->bits_per_coded_sample == 16 ? AV_SAMPLE_FMT_S16 :
00077                                                              AV_SAMPLE_FMT_S32;
00078 
00079     /* get the sample rate. Not all values are known or exist. */
00080     switch (header[2] & 0x0f) {
00081     case 1:
00082         avctx->sample_rate = 48000;
00083         break;
00084     case 4:
00085         avctx->sample_rate = 96000;
00086         break;
00087     case 5:
00088         avctx->sample_rate = 192000;
00089         break;
00090     default:
00091         avctx->sample_rate = 0;
00092         av_log(avctx, AV_LOG_ERROR, "unsupported sample rate (%d)\n",
00093                header[2] & 0x0f);
00094         return -1;
00095     }
00096 
00097     /*
00098      * get the channel number (and mapping). Not all values are known or exist.
00099      * It must be noted that the number of channels in the MPEG stream can
00100      * differ from the actual meaningful number, e.g. mono audio still has two
00101      * channels, one being empty.
00102      */
00103     avctx->channel_layout  = channel_layouts[channel_layout];
00104     avctx->channels        =        channels[channel_layout];
00105     if (!avctx->channels) {
00106         av_log(avctx, AV_LOG_ERROR, "unsupported channel configuration (%d)\n",
00107                channel_layout);
00108         return -1;
00109     }
00110 
00111     avctx->bit_rate = avctx->channels * avctx->sample_rate *
00112                       avctx->bits_per_coded_sample;
00113 
00114     if (avctx->debug & FF_DEBUG_PICT_INFO)
00115         av_dlog(avctx,
00116                 "pcm_bluray_parse_header: %d channels, %d bits per sample, %d kHz, %d kbit\n",
00117                 avctx->channels, avctx->bits_per_coded_sample,
00118                 avctx->sample_rate, avctx->bit_rate);
00119     return 0;
00120 }
00121 
00122 static int pcm_bluray_decode_frame(AVCodecContext *avctx,
00123                                    void *data,
00124                                    int *data_size,
00125                                    AVPacket *avpkt)
00126 {
00127     const uint8_t *src = avpkt->data;
00128     int buf_size = avpkt->size;
00129     int num_source_channels, channel, retval;
00130     int sample_size, samples, output_size;
00131     int16_t *dst16 = data;
00132     int32_t *dst32 = data;
00133 
00134     if (buf_size < 4) {
00135         av_log(avctx, AV_LOG_ERROR, "PCM packet too small\n");
00136         return -1;
00137     }
00138 
00139     if (pcm_bluray_parse_header(avctx, src))
00140         return -1;
00141     src += 4;
00142     buf_size -= 4;
00143 
00144     /* There's always an even number of channels in the source */
00145     num_source_channels = FFALIGN(avctx->channels, 2);
00146     sample_size = (num_source_channels * avctx->bits_per_coded_sample) >> 3;
00147     samples = buf_size / sample_size;
00148 
00149     output_size = samples * avctx->channels *
00150                   (avctx->sample_fmt == AV_SAMPLE_FMT_S32 ? 4 : 2);
00151     if (output_size > *data_size) {
00152         av_log(avctx, AV_LOG_ERROR,
00153                "Insufficient output buffer space (%d bytes, needed %d bytes)\n",
00154                *data_size, output_size);
00155         return -1;
00156     }
00157     *data_size = output_size;
00158 
00159     if (samples) {
00160         switch (avctx->channel_layout) {
00161             /* cases with same number of source and coded channels */
00162         case AV_CH_LAYOUT_STEREO:
00163         case AV_CH_LAYOUT_4POINT0:
00164         case AV_CH_LAYOUT_2_2:
00165             samples *= num_source_channels;
00166             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00167 #if HAVE_BIGENDIAN
00168                 memcpy(dst16, src, output_size);
00169 #else
00170                 do {
00171                     *dst16++ = bytestream_get_be16(&src);
00172                 } while (--samples);
00173 #endif
00174             } else {
00175                 do {
00176                     *dst32++ = bytestream_get_be24(&src) << 8;
00177                 } while (--samples);
00178             }
00179             break;
00180         /* cases where number of source channels = coded channels + 1 */
00181         case AV_CH_LAYOUT_MONO:
00182         case AV_CH_LAYOUT_SURROUND:
00183         case AV_CH_LAYOUT_2_1:
00184         case AV_CH_LAYOUT_5POINT0:
00185             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00186                 do {
00187 #if HAVE_BIGENDIAN
00188                     memcpy(dst16, src, avctx->channels * 2);
00189                     dst16 += avctx->channels;
00190                     src += sample_size;
00191 #else
00192                     channel = avctx->channels;
00193                     do {
00194                         *dst16++ = bytestream_get_be16(&src);
00195                     } while (--channel);
00196                     src += 2;
00197 #endif
00198                 } while (--samples);
00199             } else {
00200                 do {
00201                     channel = avctx->channels;
00202                     do {
00203                         *dst32++ = bytestream_get_be24(&src) << 8;
00204                     } while (--channel);
00205                     src += 3;
00206                 } while (--samples);
00207             }
00208             break;
00209             /* remapping: L, R, C, LBack, RBack, LF */
00210         case AV_CH_LAYOUT_5POINT1:
00211             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00212                 do {
00213                     dst16[0] = bytestream_get_be16(&src);
00214                     dst16[1] = bytestream_get_be16(&src);
00215                     dst16[2] = bytestream_get_be16(&src);
00216                     dst16[4] = bytestream_get_be16(&src);
00217                     dst16[5] = bytestream_get_be16(&src);
00218                     dst16[3] = bytestream_get_be16(&src);
00219                     dst16 += 6;
00220                 } while (--samples);
00221             } else {
00222                 do {
00223                     dst32[0] = bytestream_get_be24(&src) << 8;
00224                     dst32[1] = bytestream_get_be24(&src) << 8;
00225                     dst32[2] = bytestream_get_be24(&src) << 8;
00226                     dst32[4] = bytestream_get_be24(&src) << 8;
00227                     dst32[5] = bytestream_get_be24(&src) << 8;
00228                     dst32[3] = bytestream_get_be24(&src) << 8;
00229                     dst32 += 6;
00230                 } while (--samples);
00231             }
00232             break;
00233             /* remapping: L, R, C, LSide, LBack, RBack, RSide, <unused> */
00234         case AV_CH_LAYOUT_7POINT0:
00235             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00236                 do {
00237                     dst16[0] = bytestream_get_be16(&src);
00238                     dst16[1] = bytestream_get_be16(&src);
00239                     dst16[2] = bytestream_get_be16(&src);
00240                     dst16[5] = bytestream_get_be16(&src);
00241                     dst16[3] = bytestream_get_be16(&src);
00242                     dst16[4] = bytestream_get_be16(&src);
00243                     dst16[6] = bytestream_get_be16(&src);
00244                     dst16 += 7;
00245                     src += 2;
00246                 } while (--samples);
00247             } else {
00248                 do {
00249                     dst32[0] = bytestream_get_be24(&src) << 8;
00250                     dst32[1] = bytestream_get_be24(&src) << 8;
00251                     dst32[2] = bytestream_get_be24(&src) << 8;
00252                     dst32[5] = bytestream_get_be24(&src) << 8;
00253                     dst32[3] = bytestream_get_be24(&src) << 8;
00254                     dst32[4] = bytestream_get_be24(&src) << 8;
00255                     dst32[6] = bytestream_get_be24(&src) << 8;
00256                     dst32 += 7;
00257                     src += 3;
00258                 } while (--samples);
00259             }
00260             break;
00261             /* remapping: L, R, C, LSide, LBack, RBack, RSide, LF */
00262         case AV_CH_LAYOUT_7POINT1:
00263             if (AV_SAMPLE_FMT_S16 == avctx->sample_fmt) {
00264                 do {
00265                     dst16[0] = bytestream_get_be16(&src);
00266                     dst16[1] = bytestream_get_be16(&src);
00267                     dst16[2] = bytestream_get_be16(&src);
00268                     dst16[6] = bytestream_get_be16(&src);
00269                     dst16[4] = bytestream_get_be16(&src);
00270                     dst16[5] = bytestream_get_be16(&src);
00271                     dst16[7] = bytestream_get_be16(&src);
00272                     dst16[3] = bytestream_get_be16(&src);
00273                     dst16 += 8;
00274                 } while (--samples);
00275             } else {
00276                 do {
00277                     dst32[0] = bytestream_get_be24(&src) << 8;
00278                     dst32[1] = bytestream_get_be24(&src) << 8;
00279                     dst32[2] = bytestream_get_be24(&src) << 8;
00280                     dst32[6] = bytestream_get_be24(&src) << 8;
00281                     dst32[4] = bytestream_get_be24(&src) << 8;
00282                     dst32[5] = bytestream_get_be24(&src) << 8;
00283                     dst32[7] = bytestream_get_be24(&src) << 8;
00284                     dst32[3] = bytestream_get_be24(&src) << 8;
00285                     dst32 += 8;
00286                 } while (--samples);
00287             }
00288             break;
00289         }
00290     }
00291 
00292     retval = src - avpkt->data;
00293     if (avctx->debug & FF_DEBUG_BITSTREAM)
00294         av_dlog(avctx, "pcm_bluray_decode_frame: decoded %d -> %d bytes\n",
00295                 retval, *data_size);
00296     return retval;
00297 }
00298 
00299 AVCodec ff_pcm_bluray_decoder = {
00300     "pcm_bluray",
00301     AVMEDIA_TYPE_AUDIO,
00302     CODEC_ID_PCM_BLURAY,
00303     0,
00304     NULL,
00305     NULL,
00306     NULL,
00307     pcm_bluray_decode_frame,
00308     .sample_fmts = (const enum AVSampleFormat[]){AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S32,
00309                                          AV_SAMPLE_FMT_NONE},
00310     .long_name = NULL_IF_CONFIG_SMALL("PCM signed 16|20|24-bit big-endian for Blu-ray media"),
00311 };