git.sesse.net Git - ffmpeg/blob - libavcodec/tak_parser.c

   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     int ret;
  47
  48     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
  49         TAKStreamInfo ti;
  50         if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
  51             return ret;
  52         if (!ff_tak_decode_frame_header(avctx, &gb, &ti, 127))
  53             s->duration = t->ti.last_frame_samples ? t->ti.last_frame_samples
  54                                                    : t->ti.frame_samples;
  55         *poutbuf      = buf;
  56         *poutbuf_size = buf_size;
  57         return buf_size;
  58     }
  59
  60     while (buf_size || t->index + needed <= pc->index) {
  61         if (buf_size && t->index + TAK_MAX_FRAME_HEADER_BYTES > pc->index) {
  62             int tmp_buf_size       = FFMIN(2 * TAK_MAX_FRAME_HEADER_BYTES,
  63                                            buf_size);
  64             const uint8_t *tmp_buf = buf;
  65
  66             if (ff_combine_frame(pc, END_NOT_FOUND, &tmp_buf, &tmp_buf_size) != -1)
  67                 return AVERROR(ENOMEM);
  68             consumed += tmp_buf_size;
  69             buf      += tmp_buf_size;
  70             buf_size -= tmp_buf_size;
  71         }
  72
  73         for (; t->index + needed <= pc->index; t->index++) {
  74             if (pc->buffer[ t->index     ] == 0xFF &&
  75                 pc->buffer[ t->index + 1 ] == 0xA0) {
  76                 TAKStreamInfo ti;
  77
  78                 if ((ret = init_get_bits8(&gb, pc->buffer + t->index,
  79                                           pc->index - t->index)) < 0)
  80                     return ret;
  81                 if (!ff_tak_decode_frame_header(avctx, &gb,
  82                         pc->frame_start_found ? &ti : &t->ti, 127) &&
  83                     !ff_tak_check_crc(pc->buffer + t->index,
  84                                       get_bits_count(&gb) / 8)) {
  85                     if (!pc->frame_start_found) {
  86                         pc->frame_start_found = 1;
  87                         s->duration           = t->ti.last_frame_samples ?
  88                                                 t->ti.last_frame_samples :
  89                                                 t->ti.frame_samples;
  90                         s->key_frame          = !!(t->ti.flags & TAK_FRAME_FLAG_HAS_INFO);
  91                     } else {
  92                         pc->frame_start_found = 0;
  93                         next                  = t->index - pc->index;
  94                         t->index              = 0;
  95                         goto found;
  96                     }
  97                 }
  98             }
  99         }
 100     }
 101 found:
 102
 103     if (consumed && !buf_size && next == END_NOT_FOUND ||
 104         ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 105         *poutbuf      = NULL;
 106         *poutbuf_size = 0;
 107         return buf_size + consumed;
 108     }
 109
 110     if (next != END_NOT_FOUND) {
 111         next        += consumed;
 112         pc->overread = FFMAX(0, -next);
 113     }
 114
 115     *poutbuf      = buf;
 116     *poutbuf_size = buf_size;
 117     return next;
 118 }
 119
 120 AVCodecParser ff_tak_parser = {
 121     .codec_ids      = { AV_CODEC_ID_TAK },
 122     .priv_data_size = sizeof(TAKParseContext),
 123     .parser_parse   = tak_parse,
 124     .parser_close   = ff_parse_close,
 125 };