/*
  * DNxHD/VC-3 parser
  * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
  *
  * 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

  * DNxHD/VC-3 parser
  */
 
 #include "parser.h"
 

 #define DNXHD_HEADER_PREFIX 0x000002800100

 typedef struct {
     ParseContext pc;
     int interlaced;
     int cur_field; /* first field is 0, second is 1 */
 } DNXHDParserContext;
 
 static int dnxhd_find_frame_end(DNXHDParserContext *dctx,

                                 const uint8_t *buf, int buf_size)
 {

     ParseContext *pc = &dctx->pc;

     uint64_t state = pc->state64;
     int pic_found = pc->frame_start_found;
     int i = 0;

     int interlaced = dctx->interlaced;
     int cur_field = dctx->cur_field;

 
     if (!pic_found) {
         for (i = 0; i < buf_size; i++) {
             state = (state<<8) | buf[i];

             if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {

                 i++;
                 pic_found = 1;

                 interlaced = (state&2)>>1; /* byte following the 5-byte header prefix */
                 cur_field = state&1;

                 break;
             }
         }
     }
 
     if (pic_found) {
         if (!buf_size) /* EOF considered as end of frame */
             return 0;
         for (; i < buf_size; i++) {
             state = (state<<8) | buf[i];

             if ((state & 0xffffffffff00LL) == DNXHD_HEADER_PREFIX) {
                 if (!interlaced || dctx->cur_field) {
                     pc->frame_start_found = 0;
                     pc->state64 = -1;
                     dctx->interlaced = interlaced;
                     dctx->cur_field = 0;
                     return i-5;
                 } else {
                     /* continue, to get the second field */
                     dctx->interlaced = interlaced = (state&2)>>1;
                     dctx->cur_field = cur_field = state&1;
                 }

             }
         }
     }
     pc->frame_start_found = pic_found;
     pc->state64 = state;

     dctx->interlaced = interlaced;
     dctx->cur_field = cur_field;

     return END_NOT_FOUND;
 }
 
 static int dnxhd_parse(AVCodecParserContext *s,
                        AVCodecContext *avctx,
                        const uint8_t **poutbuf, int *poutbuf_size,
                        const uint8_t *buf, int buf_size)
 {

     DNXHDParserContext *dctx = s->priv_data;
     ParseContext *pc = &dctx->pc;

     int next;
 
     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
         next = buf_size;
     } else {

         next = dnxhd_find_frame_end(dctx, buf, buf_size);

         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
             *poutbuf = NULL;
             *poutbuf_size = 0;
             return buf_size;
         }
     }
     *poutbuf = buf;
     *poutbuf_size = buf_size;
     return next;
 }
 

 AVCodecParser ff_dnxhd_parser = {

     .codec_ids      = { AV_CODEC_ID_DNXHD },

     .priv_data_size = sizeof(DNXHDParserContext),

     .parser_parse   = dnxhd_parse,
     .parser_close   = ff_parse_close,

 };