/*
  * Copyright (c) 2016 Paul B Mahol
  *
  * 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 "avcodec.h"

 #include "bsf.h"

 #include "bytestream.h"
 #include "dca_syncwords.h"
 #include "libavutil/mem.h"
 

 static int dca_core_filter(AVBSFContext *ctx, AVPacket *pkt)

 {
     GetByteContext gb;
     uint32_t syncword;

     int core_size = 0, ret;

     ret = ff_bsf_get_packet_ref(ctx, pkt);

     if (ret < 0)
         return ret;
 

     bytestream2_init(&gb, pkt->data, pkt->size);

     syncword = bytestream2_get_be32(&gb);
     bytestream2_skip(&gb, 1);
 
     switch (syncword) {
     case DCA_SYNCWORD_CORE_BE:
         core_size = ((bytestream2_get_be24(&gb) >> 4) & 0x3fff) + 1;
         break;
     }
 

     if (core_size > 0 && core_size <= pkt->size) {
         pkt->size = core_size;

     }
 
     return 0;
 }
 

 static const enum AVCodecID codec_ids[] = {
     AV_CODEC_ID_DTS, AV_CODEC_ID_NONE,
 };
 
 const AVBitStreamFilter ff_dca_core_bsf = {
     .name      = "dca_core",
     .filter    = dca_core_filter,
     .codec_ids = codec_ids,

 };