Libav 0.7.1
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00001 /* 00002 * DCA parser 00003 * Copyright (C) 2004 Gildas Bazin 00004 * Copyright (C) 2004 Benjamin Zores 00005 * Copyright (C) 2006 Benjamin Larsson 00006 * Copyright (C) 2007 Konstantin Shishkov 00007 * 00008 * This file is part of Libav. 00009 * 00010 * Libav is free software; you can redistribute it and/or 00011 * modify it under the terms of the GNU Lesser General Public 00012 * License as published by the Free Software Foundation; either 00013 * version 2.1 of the License, or (at your option) any later version. 00014 * 00015 * Libav is distributed in the hope that it will be useful, 00016 * but WITHOUT ANY WARRANTY; without even the implied warranty of 00017 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00018 * Lesser General Public License for more details. 00019 * 00020 * You should have received a copy of the GNU Lesser General Public 00021 * License along with Libav; if not, write to the Free Software 00022 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 00023 */ 00024 00025 #include "parser.h" 00026 #include "dca.h" 00027 00028 typedef struct DCAParseContext { 00029 ParseContext pc; 00030 uint32_t lastmarker; 00031 int size; 00032 int framesize; 00033 int hd_pos; 00034 } DCAParseContext; 00035 00036 #define IS_MARKER(state, i, buf, buf_size) \ 00037 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \ 00038 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \ 00039 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE) 00040 00045 static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf, 00046 int buf_size) 00047 { 00048 int start_found, i; 00049 uint32_t state; 00050 ParseContext *pc = &pc1->pc; 00051 00052 start_found = pc->frame_start_found; 00053 state = pc->state; 00054 00055 i = 0; 00056 if (!start_found) { 00057 for (i = 0; i < buf_size; i++) { 00058 state = (state << 8) | buf[i]; 00059 if (IS_MARKER(state, i, buf, buf_size)) { 00060 if (pc1->lastmarker && state == pc1->lastmarker) { 00061 start_found = 1; 00062 break; 00063 } else if (!pc1->lastmarker) { 00064 start_found = 1; 00065 pc1->lastmarker = state; 00066 break; 00067 } 00068 } 00069 } 00070 } 00071 if (start_found) { 00072 for (; i < buf_size; i++) { 00073 pc1->size++; 00074 state = (state << 8) | buf[i]; 00075 if (state == DCA_HD_MARKER && !pc1->hd_pos) 00076 pc1->hd_pos = pc1->size; 00077 if (state == pc1->lastmarker && IS_MARKER(state, i, buf, buf_size)) { 00078 if(pc1->framesize > pc1->size) 00079 continue; 00080 if(!pc1->framesize){ 00081 pc1->framesize = pc1->hd_pos ? pc1->hd_pos : pc1->size; 00082 } 00083 pc->frame_start_found = 0; 00084 pc->state = -1; 00085 pc1->size = 0; 00086 return i - 3; 00087 } 00088 } 00089 } 00090 pc->frame_start_found = start_found; 00091 pc->state = state; 00092 return END_NOT_FOUND; 00093 } 00094 00095 static av_cold int dca_parse_init(AVCodecParserContext * s) 00096 { 00097 DCAParseContext *pc1 = s->priv_data; 00098 00099 pc1->lastmarker = 0; 00100 return 0; 00101 } 00102 00103 static int dca_parse(AVCodecParserContext * s, 00104 AVCodecContext * avctx, 00105 const uint8_t ** poutbuf, int *poutbuf_size, 00106 const uint8_t * buf, int buf_size) 00107 { 00108 DCAParseContext *pc1 = s->priv_data; 00109 ParseContext *pc = &pc1->pc; 00110 int next; 00111 00112 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { 00113 next = buf_size; 00114 } else { 00115 next = dca_find_frame_end(pc1, buf, buf_size); 00116 00117 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 00118 *poutbuf = NULL; 00119 *poutbuf_size = 0; 00120 return buf_size; 00121 } 00122 } 00123 *poutbuf = buf; 00124 *poutbuf_size = buf_size; 00125 return next; 00126 } 00127 00128 AVCodecParser ff_dca_parser = { 00129 {CODEC_ID_DTS}, 00130 sizeof(DCAParseContext), 00131 dca_parse_init, 00132 dca_parse, 00133 ff_parse_close, 00134 };