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#include "parser.h" 26#include "dca.h" 27 28typedef struct DCAParseContext { 29 ParseContext pc; 30 uint32_t lastmarker; 31 int size; 32 int framesize; 33 int hd_pos; 34} DCAParseContext; 35 36#define IS_MARKER(state, i, buf, buf_size) \ 37 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \ 38 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \ 39 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE) 40 41/** 42 * finds the end of the current frame in the bitstream. 43 * @return the position of the first byte of the next frame, or -1 44 */ 45static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf, 46 int buf_size) 47{ 48 int start_found, i; 49 uint32_t state; 50 ParseContext *pc = &pc1->pc; 51 52 start_found = pc->frame_start_found; 53 state = pc->state; 54 55 i = 0; 56 if (!start_found) { 57 for (i = 0; i < buf_size; i++) { 58 state = (state << 8) | buf[i]; 59 if (IS_MARKER(state, i, buf, buf_size)) { 60 if (pc1->lastmarker && state == pc1->lastmarker) { 61 start_found = 1; 62 break; 63 } else if (!pc1->lastmarker) { 64 start_found = 1; 65 pc1->lastmarker = state; 66 break; 67 } 68 } 69 } 70 } 71 if (start_found) { 72 for (; i < buf_size; i++) { 73 pc1->size++; 74 state = (state << 8) | buf[i]; 75 if (state == DCA_HD_MARKER && !pc1->hd_pos) 76 pc1->hd_pos = pc1->size; 77 if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) { 78 if(pc1->framesize > pc1->size) 79 continue; 80 if(!pc1->framesize){ 81 pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size; 82 } 83 pc->frame_start_found = 0; 84 pc->state = -1; 85 pc1->size = 0; 86 return i - 3; 87 } 88 } 89 } 90 pc->frame_start_found = start_found; 91 pc->state = state; 92 return END_NOT_FOUND; 93} 94 95static av_cold int dca_parse_init(AVCodecParserContext * s) 96{ 97 DCAParseContext *pc1 = s->priv_data; 98 99 pc1->lastmarker = 0; 100 return 0; 101} 102 103static int dca_parse(AVCodecParserContext * s, 104 AVCodecContext * avctx, 105 const uint8_t ** poutbuf, int *poutbuf_size, 106 const uint8_t * buf, int buf_size) 107{ 108 DCAParseContext *pc1 = s->priv_data; 109 ParseContext *pc = &pc1->pc; 110 int next; 111 112 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { 113 next = buf_size; 114 } else { 115 next = dca_find_frame_end(pc1, buf, buf_size); 116 117 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 118 *poutbuf = NULL; 119 *poutbuf_size = 0; 120 return buf_size; 121 } 122 } 123 *poutbuf = buf; 124 *poutbuf_size = buf_size; 125 return next; 126} 127 128AVCodecParser dca_parser = { 129 {CODEC_ID_DTS}, 130 sizeof(DCAParseContext), 131 dca_parse_init, 132 dca_parse, 133 ff_parse_close, 134}; 135