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 Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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 BITSTREAM_READER_LE
  28 #include "bitstream.h"
  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 av_cold int tak_init(AVCodecParserContext *s)
  39 {
  40     ff_tak_init_crc();
  41     return 0;
  42 }
  43
  44 static int tak_parse(AVCodecParserContext *s, AVCodecContext *avctx,
  45                      const uint8_t **poutbuf, int *poutbuf_size,
  46                      const uint8_t *buf, int buf_size)
  47 {
  48     TAKParseContext *t = s->priv_data;
  49     ParseContext *pc   = &t->pc;
  50     int next           = END_NOT_FOUND;
  51     BitstreamContext bc;
  52     int consumed = 0;
  53     int needed   = buf_size ? TAK_MAX_FRAME_HEADER_BYTES : 8;
  54
  55     if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
  56         TAKStreamInfo ti;
  57         bitstream_init(&bc, buf, buf_size);
  58         if (!ff_tak_decode_frame_header(avctx, &bc, &ti, 127))
  59             s->duration = t->ti.last_frame_samples ? t->ti.last_frame_samples
  60                                                    : t->ti.frame_samples;
  61         *poutbuf      = buf;
  62         *poutbuf_size = buf_size;
  63         return buf_size;
  64     }
  65
  66     while (buf_size || t->index + needed <= pc->index) {
  67         if (buf_size && t->index + TAK_MAX_FRAME_HEADER_BYTES > pc->index) {
  68             int tmp_buf_size       = FFMIN(2 * TAK_MAX_FRAME_HEADER_BYTES,
  69                                            buf_size);
  70             const uint8_t *tmp_buf = buf;
  71
  72             ff_combine_frame(pc, END_NOT_FOUND, &tmp_buf, &tmp_buf_size);
  73             consumed += tmp_buf_size;
  74             buf      += tmp_buf_size;
  75             buf_size -= tmp_buf_size;
  76         }
  77
  78         for (; t->index + needed <= pc->index; t->index++)
  79             if (pc->buffer[t->index]     == 0xFF &&
  80                 pc->buffer[t->index + 1] == 0xA0) {
  81                 TAKStreamInfo ti;
  82
  83                 bitstream_init8(&bc, pc->buffer + t->index,
  84                                 pc->index - t->index);
  85                 if (!ff_tak_decode_frame_header(avctx, &bc,
  86                                                 pc->frame_start_found ? &ti
  87                                                                       : &t->ti,
  88                                                 127) &&
  89                     !ff_tak_check_crc(pc->buffer + t->index,
  90                                       bitstream_tell(&bc) / 8)) {
  91                     if (!pc->frame_start_found) {
  92                         pc->frame_start_found = 1;
  93                         s->duration           = t->ti.last_frame_samples ?
  94                                                 t->ti.last_frame_samples :
  95                                                 t->ti.frame_samples;
  96                     } else {
  97                         pc->frame_start_found = 0;
  98                         next                  = t->index - pc->index;
  99                         t->index              = 0;
 100                         goto found;
 101                     }
 102                 }
 103             }
 104     }
 105
 106 found:
 107     if (consumed && !buf_size && next == END_NOT_FOUND ||
 108         ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
 109         *poutbuf      = NULL;
 110         *poutbuf_size = 0;
 111         return buf_size + consumed;
 112     }
 113
 114     if (next != END_NOT_FOUND) {
 115         next        += consumed;
 116         pc->overread = FFMAX(0, -next);
 117     }
 118
 119     *poutbuf      = buf;
 120     *poutbuf_size = buf_size;
 121     return next;
 122 }
 123
 124 AVCodecParser ff_tak_parser = {
 125     .codec_ids      = { AV_CODEC_ID_TAK },
 126     .priv_data_size = sizeof(TAKParseContext),
 127     .parser_init    = tak_init,
 128     .parser_parse   = tak_parse,
 129     .parser_close   = ff_parse_close,
 130 };