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  1. /*
  2.  * TAK parser
  3.  * Copyright (c) 2012 Michael Niedermayer
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * TAK parser
  25.  **/
  26.  
  27. #include "tak.h"
  28. #include "parser.h"
  29.  
  30. typedef struct TAKParseContext {
  31.     ParseContext  pc;
  32.     TAKStreamInfo ti;
  33.     int           index;
  34. } TAKParseContext;
  35.  
  36. static int tak_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  37.                      const uint8_t **poutbuf, int *poutbuf_size,
  38.                      const uint8_t *buf, int buf_size)
  39. {
  40.     TAKParseContext *t = s->priv_data;
  41.     ParseContext *pc   = &t->pc;
  42.     int next           = END_NOT_FOUND;
  43.     GetBitContext gb;
  44.     int consumed = 0;
  45.     int needed   = buf_size ? TAK_MAX_FRAME_HEADER_BYTES : 8;
  46.  
  47.     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
  48.         TAKStreamInfo ti;
  49.         init_get_bits(&gb, buf, buf_size);
  50.         if (!ff_tak_decode_frame_header(avctx, &gb, &ti, 127))
  51.             s->duration = t->ti.last_frame_samples ? t->ti.last_frame_samples
  52.                                                    : t->ti.frame_samples;
  53.         *poutbuf      = buf;
  54.         *poutbuf_size = buf_size;
  55.         return buf_size;
  56.     }
  57.  
  58.     while (buf_size || t->index + needed <= pc->index) {
  59.         if (buf_size && t->index + TAK_MAX_FRAME_HEADER_BYTES > pc->index) {
  60.             int tmp_buf_size       = FFMIN(2 * TAK_MAX_FRAME_HEADER_BYTES,
  61.                                            buf_size);
  62.             const uint8_t *tmp_buf = buf;
  63.  
  64.             if (ff_combine_frame(pc, END_NOT_FOUND, &tmp_buf, &tmp_buf_size) != -1)
  65.                 return AVERROR(ENOMEM);
  66.             consumed += tmp_buf_size;
  67.             buf      += tmp_buf_size;
  68.             buf_size -= tmp_buf_size;
  69.         }
  70.  
  71.         for (; t->index + needed <= pc->index; t->index++) {
  72.             if (pc->buffer[ t->index     ] == 0xFF &&
  73.                 pc->buffer[ t->index + 1 ] == 0xA0) {
  74.                 TAKStreamInfo ti;
  75.  
  76.                 init_get_bits(&gb, pc->buffer + t->index,
  77.                               8 * (pc->index - t->index));
  78.                 if (!ff_tak_decode_frame_header(avctx, &gb,
  79.                         pc->frame_start_found ? &ti : &t->ti, 127) &&
  80.                     !ff_tak_check_crc(pc->buffer + t->index,
  81.                                       get_bits_count(&gb) / 8)) {
  82.                     if (!pc->frame_start_found) {
  83.                         pc->frame_start_found = 1;
  84.                         s->duration           = t->ti.last_frame_samples ?
  85.                                                 t->ti.last_frame_samples :
  86.                                                 t->ti.frame_samples;
  87.                         s->key_frame          = !!(t->ti.flags & TAK_FRAME_FLAG_HAS_INFO);
  88.                     } else {
  89.                         pc->frame_start_found = 0;
  90.                         next                  = t->index - pc->index;
  91.                         t->index              = 0;
  92.                         goto found;
  93.                     }
  94.                 }
  95.             }
  96.         }
  97.     }
  98. found:
  99.  
  100.     if (consumed && !buf_size && next == END_NOT_FOUND ||
  101.         ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
  102.         *poutbuf      = NULL;
  103.         *poutbuf_size = 0;
  104.         return buf_size + consumed;
  105.     }
  106.  
  107.     if (next != END_NOT_FOUND) {
  108.         next        += consumed;
  109.         pc->overread = FFMAX(0, -next);
  110.     }
  111.  
  112.     *poutbuf      = buf;
  113.     *poutbuf_size = buf_size;
  114.     return next;
  115. }
  116.  
  117. AVCodecParser ff_tak_parser = {
  118.     .codec_ids      = { AV_CODEC_ID_TAK },
  119.     .priv_data_size = sizeof(TAKParseContext),
  120.     .parser_parse   = tak_parse,
  121.     .parser_close   = ff_parse_close,
  122. };
  123.