1/* 2 * DCA parser 3 * Copyright (C) 2004 Gildas Bazin 4 * Copyright (C) 2004 Benjamin Zores 5 * Copyright (C) 2006 Benjamin Larsson 6 * Copyright (C) 2007 Konstantin Shishkov 7 * 8 * This file is part of FFmpeg. 9 * 10 * FFmpeg is free software; you can redistribute it and/or 11 * modify it under the terms of the GNU Lesser General Public 12 * License as published by the Free Software Foundation; either 13 * version 2.1 of the License, or (at your option) any later version. 14 * 15 * FFmpeg is distributed in the hope that it will be useful, 16 * but WITHOUT ANY WARRANTY; without even the implied warranty of 17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 18 * Lesser General Public License for more details. 19 * 20 * You should have received a copy of the GNU Lesser General Public 21 * License along with FFmpeg; if not, write to the Free Software 22 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 23 */ 24 25/** 26 * @file libavcodec/dca_parser.c 27 */ 28 29#include "parser.h" 30#include "dca.h" 31 32typedef struct DCAParseContext { 33 ParseContext pc; 34 uint32_t lastmarker; 35 int size; 36 int framesize; 37 int hd_pos; 38} DCAParseContext; 39 40#define IS_MARKER(state, i, buf, buf_size) \ 41 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \ 42 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \ 43 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE) 44 45/** 46 * finds the end of the current frame in the bitstream. 47 * @return the position of the first byte of the next frame, or -1 48 */ 49static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf, 50 int buf_size) 51{ 52 int start_found, i; 53 uint32_t state; 54 ParseContext *pc = &pc1->pc; 55 56 start_found = pc->frame_start_found; 57 state = pc->state; 58 59 i = 0; 60 if (!start_found) { 61 for (i = 0; i < buf_size; i++) { 62 state = (state << 8) | buf[i]; 63 if (IS_MARKER(state, i, buf, buf_size)) { 64 if (pc1->lastmarker && state == pc1->lastmarker) { 65 start_found = 1; 66 break; 67 } else if (!pc1->lastmarker) { 68 start_found = 1; 69 pc1->lastmarker = state; 70 break; 71 } 72 } 73 } 74 } 75 if (start_found) { 76 for (; i < buf_size; i++) { 77 pc1->size++; 78 state = (state << 8) | buf[i]; 79 if (state == DCA_HD_MARKER && !pc1->hd_pos) 80 pc1->hd_pos = pc1->size; 81 if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) { 82 if(pc1->framesize > pc1->size) 83 continue; 84 if(!pc1->framesize){ 85 pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size; 86 } 87 pc->frame_start_found = 0; 88 pc->state = -1; 89 pc1->size = 0; 90 return i - 3; 91 } 92 } 93 } 94 pc->frame_start_found = start_found; 95 pc->state = state; 96 return END_NOT_FOUND; 97} 98 99static av_cold int dca_parse_init(AVCodecParserContext * s) 100{ 101 DCAParseContext *pc1 = s->priv_data; 102 103 pc1->lastmarker = 0; 104 return 0; 105} 106 107static int dca_parse(AVCodecParserContext * s, 108 AVCodecContext * avctx, 109 const uint8_t ** poutbuf, int *poutbuf_size, 110 const uint8_t * buf, int buf_size) 111{ 112 DCAParseContext *pc1 = s->priv_data; 113 ParseContext *pc = &pc1->pc; 114 int next; 115 116 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { 117 next = buf_size; 118 } else { 119 next = dca_find_frame_end(pc1, buf, buf_size); 120 121 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 122 *poutbuf = NULL; 123 *poutbuf_size = 0; 124 return buf_size; 125 } 126 } 127 *poutbuf = buf; 128 *poutbuf_size = buf_size; 129 return next; 130} 131 132AVCodecParser dca_parser = { 133 {CODEC_ID_DTS}, 134 sizeof(DCAParseContext), 135 dca_parse_init, 136 dca_parse, 137 ff_parse_close, 138}; 139