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 #define CACHED_BITSTREAM_READER !ARCH_X86_32
  28 #define BITSTREAM_READER_LE
  29 #include "parser.h"
  30 #include "tak.h"
  31
  32 typedef struct TAKParseContext {
  33     ParseContext  pc;
  34     TAKStreamInfo ti;
  35     int           index;
  36 } TAKParseContext;
  37
  38 static int tak_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  39                      const uint8_t **poutbuf, int *poutbuf_size,
  40                      const uint8_t *buf, int buf_size)
  41 {
  42     TAKParseContext *t = s->priv_data;
  43     ParseContext *pc   = &t->pc;
  44     int next           = END_NOT_FOUND;
  45     GetBitContext gb;
  46     int consumed = 0;
  47     int needed   = buf_size ? TAK_MAX_FRAME_HEADER_BYTES : 8;
  48     int ret;
  49
  50     *poutbuf      = buf;
  51     *poutbuf_size = buf_size;
  52
  53     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
  54         TAKStreamInfo ti;
  55         if ((ret = init_get_bits8(&gb, buf, buf_size)) < 0)
  56             return buf_size;
  57         if (!ff_tak_decode_frame_header(avctx, &gb, &ti, 127))
  58             s->duration = t->ti.last_frame_samples ? t->ti.last_frame_samples
  59                                                    : t->ti.frame_samples;
  60         return buf_size;
  61     }
  62
  63     while (buf_size || t->index + needed <= pc->index) {
  64         if (buf_size && t->index + TAK_MAX_FRAME_HEADER_BYTES > pc->index) {
  65             int tmp_buf_size       = FFMIN(TAK_MAX_FRAME_HEADER_BYTES,
  66                                            buf_size);
  67             const uint8_t *tmp_buf = buf;
  68
  69             if (ff_combine_frame(pc, END_NOT_FOUND, &tmp_buf, &tmp_buf_size) != -1)
  70                 goto fail;
  71             consumed += tmp_buf_size;
  72             buf      += tmp_buf_size;
  73             buf_size -= tmp_buf_size;
  74         }
  75
  76         for (; t->index + needed <= pc->index; t->index++) {
  77             if (pc->buffer[ t->index     ] == 0xFF &&
  78                 pc->buffer[ t->index + 1 ] == 0xA0) {
  79                 TAKStreamInfo ti;
  80
  81                 if ((ret = init_get_bits8(&gb, pc->buffer + t->index,
  82                                           pc->index - t->index)) < 0)
  83                     goto fail;
  84                 if (!ff_tak_decode_frame_header(avctx, &gb,
  85                         pc->frame_start_found ? &ti : &t->ti, 127) &&
  86                     !ff_tak_check_crc(pc->buffer + t->index,
  87                                       get_bits_count(&gb) / 8)) {
  88                     if (!pc->frame_start_found) {
  89                         pc->frame_start_found = 1;
  90                         s->duration           = t->ti.last_frame_samples ?
  91                                                 t->ti.last_frame_samples :
  92                                                 t->ti.frame_samples;
  93                         s->key_frame          = !!(t->ti.flags & TAK_FRAME_FLAG_HAS_INFO);
  94                     } else {
  95                         pc->frame_start_found = 0;
  96                         next                  = t->index - pc->index;
  97                         t->index              = 0;
  98                         goto found;
  99                     }
 100                 }
 101             }
 102         }
 103     }
 104 found:
 105
 106     if (consumed && !buf_size && next == END_NOT_FOUND ||
 107         ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 108         goto fail;
 109     }
 110
 111     if (next != END_NOT_FOUND) {
 112         next        += consumed;
 113         pc->overread = FFMAX(0, -next);
 114     }
 115
 116     *poutbuf      = buf;
 117     *poutbuf_size = buf_size;
 118     return next;
 119
 120 fail:
 121     *poutbuf      = NULL;
 122     *poutbuf_size = 0;
 123     return buf_size + consumed;
 124 }
 125
 126 const AVCodecParser ff_tak_parser = {
 127     .codec_ids      = { AV_CODEC_ID_TAK },
 128     .priv_data_size = sizeof(TAKParseContext),
 129     .parser_parse   = tak_parse,
 130     .parser_close   = ff_parse_close,
 131 };