/*
  * MLP parser
  * Copyright (c) 2007 Ian Caulfield
  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**

  * @file

  * MLP parser
  */
 

 #include <stdint.h>
 

 #include "libavutil/crc.h"

 #include "libavutil/audioconvert.h"

 #include "get_bits.h"

 #include "parser.h"
 #include "mlp_parser.h"

 #include "mlp.h"

 
 static const uint8_t mlp_quants[16] = {
     16, 20, 24, 0, 0, 0, 0, 0,
      0,  0,  0, 0, 0, 0, 0, 0,
 };
 
 static const uint8_t mlp_channels[32] = {
     1, 2, 3, 4, 3, 4, 5, 3, 4, 5, 4, 5, 6, 4, 5, 4,
     5, 6, 5, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
 };
 

 const uint64_t ff_mlp_layout[32] = {

     AV_CH_LAYOUT_MONO,
     AV_CH_LAYOUT_STEREO,
     AV_CH_LAYOUT_2_1,

     AV_CH_LAYOUT_QUAD,

     AV_CH_LAYOUT_STEREO|AV_CH_LOW_FREQUENCY,
     AV_CH_LAYOUT_2_1|AV_CH_LOW_FREQUENCY,

     AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,

     AV_CH_LAYOUT_SURROUND,
     AV_CH_LAYOUT_4POINT0,

     AV_CH_LAYOUT_5POINT0_BACK,

     AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
     AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,

     AV_CH_LAYOUT_5POINT1_BACK,

     AV_CH_LAYOUT_4POINT0,

     AV_CH_LAYOUT_5POINT0_BACK,

     AV_CH_LAYOUT_SURROUND|AV_CH_LOW_FREQUENCY,
     AV_CH_LAYOUT_4POINT0|AV_CH_LOW_FREQUENCY,

     AV_CH_LAYOUT_5POINT1_BACK,
     AV_CH_LAYOUT_QUAD|AV_CH_LOW_FREQUENCY,
     AV_CH_LAYOUT_5POINT0_BACK,
     AV_CH_LAYOUT_5POINT1_BACK,

     0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 };
 

 static const uint8_t thd_chancount[13] = {
 //  LR    C   LFE  LRs LRvh  LRc LRrs  Cs   Ts  LRsd  LRw  Cvh  LFE2
      2,   1,   1,   2,   2,   2,   2,   1,   1,   2,   2,   1,   1
 };
 

 static const uint64_t thd_layout[13] = {
     AV_CH_FRONT_LEFT|AV_CH_FRONT_RIGHT,                     // LR
     AV_CH_FRONT_CENTER,                                     // C
     AV_CH_LOW_FREQUENCY,                                    // LFE
     AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT,                       // LRs
     AV_CH_TOP_FRONT_LEFT|AV_CH_TOP_FRONT_RIGHT,             // LRvh
     AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT,                       // LRc
     AV_CH_BACK_LEFT|AV_CH_BACK_RIGHT,                       // LRrs
     AV_CH_BACK_CENTER,                                      // Cs
     AV_CH_TOP_BACK_CENTER,                                  // Ts
     AV_CH_SIDE_LEFT|AV_CH_SIDE_RIGHT,                       // LRsd
     AV_CH_FRONT_LEFT_OF_CENTER|AV_CH_FRONT_RIGHT_OF_CENTER, // LRw
     AV_CH_TOP_BACK_CENTER,                                  // Cvh
     AV_CH_LOW_FREQUENCY                                     // LFE2
 };
 

 static int mlp_samplerate(int in)
 {
     if (in == 0xF)
         return 0;
 
     return (in & 8 ? 44100 : 48000) << (in & 7) ;
 }
 
 static int truehd_channels(int chanmap)
 {
     int channels = 0, i;
 
     for (i = 0; i < 13; i++)
         channels += thd_chancount[i] * ((chanmap >> i) & 1);
 
     return channels;
 }
 

 int64_t ff_truehd_layout(int chanmap)

 {
     int layout = 0, i;
 
     for (i = 0; i < 13; i++)
         layout |= thd_layout[i] * ((chanmap >> i) & 1);
 
     return layout;
 }
 

 /** Read a major sync info header - contains high level information about
  *  the stream - sample rate, channel arrangement etc. Most of this
  *  information is not actually necessary for decoding, only for playback.

  *  gb must be a freshly initialized GetBitContext with no bits read.

  */
 

 int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)

 {
     int ratebits;
     uint16_t checksum;
 

     assert(get_bits_count(gb) == 0);
 
     if (gb->size_in_bits < 28 << 3) {

         av_log(log, AV_LOG_ERROR, "packet too short, unable to read major sync\n");

         return -1;
     }
 

     checksum = ff_mlp_checksum16(gb->buffer, 26);

     if (checksum != AV_RL16(gb->buffer+26)) {

         av_log(log, AV_LOG_ERROR, "major sync info header checksum error\n");

         return -1;
     }
 

     if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */

         return -1;
 

     mh->stream_type = get_bits(gb, 8);

 
     if (mh->stream_type == 0xbb) {

         mh->group1_bits = mlp_quants[get_bits(gb, 4)];
         mh->group2_bits = mlp_quants[get_bits(gb, 4)];

         ratebits = get_bits(gb, 4);

         mh->group1_samplerate = mlp_samplerate(ratebits);

         mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));

         skip_bits(gb, 11);

         mh->channels_mlp = get_bits(gb, 5);

     } else if (mh->stream_type == 0xba) {
         mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
         mh->group2_bits = 0;
 

         ratebits = get_bits(gb, 4);

         mh->group1_samplerate = mlp_samplerate(ratebits);
         mh->group2_samplerate = 0;
 

         skip_bits(gb, 8);

         mh->channels_thd_stream1 = get_bits(gb, 5);

         skip_bits(gb, 2);

         mh->channels_thd_stream2 = get_bits(gb, 13);

     } else
         return -1;
 
     mh->access_unit_size = 40 << (ratebits & 7);
     mh->access_unit_size_pow2 = 64 << (ratebits & 7);
 

     skip_bits_long(gb, 48);

     mh->is_vbr = get_bits1(gb);

     mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;

     mh->num_substreams = get_bits(gb, 4);

     skip_bits_long(gb, 4 + 11 * 8);

 
     return 0;
 }
 
 typedef struct MLPParseContext
 {
     ParseContext pc;
 
     int bytes_left;
 
     int in_sync;
 
     int num_substreams;
 } MLPParseContext;
 

 static av_cold int mlp_init(AVCodecParserContext *s)
 {
     ff_mlp_init_crc();
     return 0;
 }
 

 static int mlp_parse(AVCodecParserContext *s,
                      AVCodecContext *avctx,
                      const uint8_t **poutbuf, int *poutbuf_size,
                      const uint8_t *buf, int buf_size)
 {
     MLPParseContext *mp = s->priv_data;
     int sync_present;
     uint8_t parity_bits;
     int next;
     int i, p = 0;
 
     *poutbuf_size = 0;
     if (buf_size == 0)
         return 0;
 
     if (!mp->in_sync) {
         // Not in sync - find a major sync header
 
         for (i = 0; i < buf_size; i++) {
             mp->pc.state = (mp->pc.state << 8) | buf[i];

             if ((mp->pc.state & 0xfffffffe) == 0xf8726fba &&
                 // ignore if we do not have the data for the start of header
                 mp->pc.index + i >= 7) {

                 mp->in_sync = 1;
                 mp->bytes_left = 0;
                 break;
             }
         }
 
         if (!mp->in_sync) {
             ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
             return buf_size;
         }
 
         ff_combine_frame(&mp->pc, i - 7, &buf, &buf_size);
 
         return i - 7;
     }
 
     if (mp->bytes_left == 0) {
         // Find length of this packet
 
         /* Copy overread bytes from last frame into buffer. */
         for(; mp->pc.overread>0; mp->pc.overread--) {
             mp->pc.buffer[mp->pc.index++]= mp->pc.buffer[mp->pc.overread_index++];
         }
 
         if (mp->pc.index + buf_size < 2) {
             ff_combine_frame(&mp->pc, END_NOT_FOUND, &buf, &buf_size);
             return buf_size;
         }
 
         mp->bytes_left = ((mp->pc.index > 0 ? mp->pc.buffer[0] : buf[0]) << 8)
                        |  (mp->pc.index > 1 ? mp->pc.buffer[1] : buf[1-mp->pc.index]);
         mp->bytes_left = (mp->bytes_left & 0xfff) * 2;
         mp->bytes_left -= mp->pc.index;
     }
 
     next = (mp->bytes_left > buf_size) ? END_NOT_FOUND : mp->bytes_left;
 
     if (ff_combine_frame(&mp->pc, next, &buf, &buf_size) < 0) {
         mp->bytes_left -= buf_size;
         return buf_size;
     }
 
     mp->bytes_left = 0;
 
     sync_present = (AV_RB32(buf + 4) & 0xfffffffe) == 0xf8726fba;
 
     if (!sync_present) {

         /* The first nibble of a frame is a parity check of the 4-byte
          * access unit header and all the 2- or 4-byte substream headers. */

         // Only check when this isn't a sync frame - syncs have a checksum.

 
         parity_bits = 0;

         for (i = -1; i < mp->num_substreams; i++) {

             parity_bits ^= buf[p++];
             parity_bits ^= buf[p++];
 

             if (i < 0 || buf[p-2] & 0x80) {

                 parity_bits ^= buf[p++];
                 parity_bits ^= buf[p++];
             }
         }
 
         if ((((parity_bits >> 4) ^ parity_bits) & 0xF) != 0xF) {

             av_log(avctx, AV_LOG_INFO, "mlpparse: Parity check failed.\n");

             goto lost_sync;
         }
     } else {

         GetBitContext gb;

         MLPHeaderInfo mh;
 

         init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
         if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)

             goto lost_sync;
 

         avctx->bits_per_raw_sample = mh.group1_bits;
         if (avctx->bits_per_raw_sample > 16)

             avctx->sample_fmt = AV_SAMPLE_FMT_S32;

         else

             avctx->sample_fmt = AV_SAMPLE_FMT_S16;

         avctx->sample_rate = mh.group1_samplerate;
         avctx->frame_size = mh.access_unit_size;
 
         if (mh.stream_type == 0xbb) {
             /* MLP stream */
             avctx->channels = mlp_channels[mh.channels_mlp];

             avctx->channel_layout = ff_mlp_layout[mh.channels_mlp];

         } else { /* mh.stream_type == 0xba */
             /* TrueHD stream */

             if (mh.channels_thd_stream2) {

                 avctx->channels = truehd_channels(mh.channels_thd_stream2);

                 avctx->channel_layout = ff_truehd_layout(mh.channels_thd_stream2);

             } else {

                 avctx->channels = truehd_channels(mh.channels_thd_stream1);

                 avctx->channel_layout = ff_truehd_layout(mh.channels_thd_stream1);

             }

         }
 
         if (!mh.is_vbr) /* Stream is CBR */
             avctx->bit_rate = mh.peak_bitrate;
 
         mp->num_substreams = mh.num_substreams;
     }
 
     *poutbuf = buf;
     *poutbuf_size = buf_size;
 
     return next;
 
 lost_sync:
     mp->in_sync = 0;

     return 1;

 }
 

 AVCodecParser ff_mlp_parser = {

     { CODEC_ID_MLP, CODEC_ID_TRUEHD },

     sizeof(MLPParseContext),

     mlp_init,

     mlp_parse,

     ff_parse_close,

 };