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