/*
  * MPEG-4 Audio common code
  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>

  * Copyright (c) 2009 Alex Converse <alex.converse@gmail.com>

  *
  * 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
  */
 

 #include "get_bits.h"

 #include "put_bits.h"

 #include "mpeg4audio.h"
 

 /**
  * Parse MPEG-4 audio configuration for ALS object type.
  * @param[in] gb       bit reader context
  * @param[in] c        MPEG4AudioConfig structure to fill
  * @return on success 0 is returned, otherwise a value < 0
  */
 static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
 {

     if (get_bits_left(gb) < 112)

         return -1;
 
     if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
         return -1;
 
     // override AudioSpecificConfig channel configuration and sample rate
     // which are buggy in old ALS conformance files
     c->sample_rate = get_bits_long(gb, 32);
 
     // skip number of samples
     skip_bits_long(gb, 32);
 
     // read number of channels
     c->chan_config = 0;
     c->channels    = get_bits(gb, 16) + 1;
 
     return 0;
 }
 

 /* XXX: make sure to update the copies in the different encoders if you change
  * this table */

 const int avpriv_mpeg4audio_sample_rates[16] = {

     96000, 88200, 64000, 48000, 44100, 32000,
     24000, 22050, 16000, 12000, 11025, 8000, 7350
 };
 
 const uint8_t ff_mpeg4audio_channels[8] = {
     0, 1, 2, 3, 4, 5, 6, 8
 };
 
 static inline int get_object_type(GetBitContext *gb)
 {
     int object_type = get_bits(gb, 5);

     if (object_type == AOT_ESCAPE)

         object_type = 32 + get_bits(gb, 6);
     return object_type;
 }
 
 static inline int get_sample_rate(GetBitContext *gb, int *index)
 {
     *index = get_bits(gb, 4);
     return *index == 0x0f ? get_bits(gb, 24) :

         avpriv_mpeg4audio_sample_rates[*index];

 }
 

 int avpriv_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf,
                                  int bit_size, int sync_extension)

 {
     GetBitContext gb;
     int specific_config_bitindex;
 

     if(bit_size<=0)
         return AVERROR_INVALIDDATA;
 

     init_get_bits(&gb, buf, bit_size);

     c->object_type = get_object_type(&gb);
     c->sample_rate = get_sample_rate(&gb, &c->sampling_index);
     c->chan_config = get_bits(&gb, 4);

     if (c->chan_config < FF_ARRAY_ELEMS(ff_mpeg4audio_channels))
         c->channels = ff_mpeg4audio_channels[c->chan_config];

     c->sbr = -1;

     c->ps  = -1;

     if (c->object_type == AOT_SBR || (c->object_type == AOT_PS &&
         // check for W6132 Annex YYYY draft MP3onMP4
         !(show_bits(&gb, 3) & 0x03 && !(show_bits(&gb, 9) & 0x3F)))) {

         if (c->object_type == AOT_PS)
             c->ps = 1;

         c->ext_object_type = AOT_SBR;

         c->sbr = 1;
         c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);
         c->object_type = get_object_type(&gb);

         if (c->object_type == AOT_ER_BSAC)
             c->ext_chan_config = get_bits(&gb, 4);

     } else {

         c->ext_object_type = AOT_NULL;

         c->ext_sample_rate = 0;
     }

     specific_config_bitindex = get_bits_count(&gb);
 

     if (c->object_type == AOT_ALS) {
         skip_bits(&gb, 5);
         if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
             skip_bits_long(&gb, 24);
 
         specific_config_bitindex = get_bits_count(&gb);
 
         if (parse_config_ALS(&gb, c))
             return -1;
     }
 

     if (c->ext_object_type != AOT_SBR && sync_extension) {

         while (get_bits_left(&gb) > 15) {

             if (show_bits(&gb, 11) == 0x2b7) { // sync extension
                 get_bits(&gb, 11);
                 c->ext_object_type = get_object_type(&gb);

                 if (c->ext_object_type == AOT_SBR && (c->sbr = get_bits1(&gb)) == 1) {

                     c->ext_sample_rate = get_sample_rate(&gb, &c->ext_sampling_index);

                     if (c->ext_sample_rate == c->sample_rate)
                         c->sbr = -1;
                 }

                 if (get_bits_left(&gb) > 11 && get_bits(&gb, 11) == 0x548)
                     c->ps = get_bits1(&gb);

                 break;
             } else
                 get_bits1(&gb); // skip 1 bit
         }
     }

 
     //PS requires SBR
     if (!c->sbr)
         c->ps = 0;
     //Limit implicit PS to the HE-AACv2 Profile
     if ((c->ps == -1 && c->object_type != AOT_AAC_LC) || c->channels & ~0x01)
         c->ps = 0;
 

     return specific_config_bitindex;
 }

 
 static av_always_inline unsigned int copy_bits(PutBitContext *pb,
                                                GetBitContext *gb,
                                                int bits)
 {
     unsigned int el = get_bits(gb, bits);
     put_bits(pb, bits, el);
     return el;
 }
 

 int avpriv_copy_pce_data(PutBitContext *pb, GetBitContext *gb)

 {
     int five_bit_ch, four_bit_ch, comment_size, bits;
     int offset = put_bits_count(pb);
 
     copy_bits(pb, gb, 10);                  //Tag, Object Type, Frequency
     five_bit_ch  = copy_bits(pb, gb, 4);    //Front
     five_bit_ch += copy_bits(pb, gb, 4);    //Side
     five_bit_ch += copy_bits(pb, gb, 4);    //Back
     four_bit_ch  = copy_bits(pb, gb, 2);    //LFE
     four_bit_ch += copy_bits(pb, gb, 3);    //Data
     five_bit_ch += copy_bits(pb, gb, 4);    //Coupling
     if (copy_bits(pb, gb, 1))               //Mono Mixdown
         copy_bits(pb, gb, 4);
     if (copy_bits(pb, gb, 1))               //Stereo Mixdown
         copy_bits(pb, gb, 4);
     if (copy_bits(pb, gb, 1))               //Matrix Mixdown
         copy_bits(pb, gb, 3);
     for (bits = five_bit_ch*5+four_bit_ch*4; bits > 16; bits -= 16)
         copy_bits(pb, gb, 16);
     if (bits)
         copy_bits(pb, gb, bits);

     avpriv_align_put_bits(pb);

     align_get_bits(gb);
     comment_size = copy_bits(pb, gb, 8);
     for (; comment_size > 0; comment_size--)
         copy_bits(pb, gb, 8);
 
     return put_bits_count(pb) - offset;
 }