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
  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 };