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#include "get_bits.h" 28 29typedef struct DCAParseContext { 30 ParseContext pc; 31 uint32_t lastmarker; 32 int size; 33 int framesize; 34 int hd_pos; 35} DCAParseContext; 36 37#define IS_MARKER(state, i, buf, buf_size) \ 38 ((state == DCA_MARKER_14B_LE && (i < buf_size-2) && (buf[i+1] & 0xF0) == 0xF0 && buf[i+2] == 0x07) \ 39 || (state == DCA_MARKER_14B_BE && (i < buf_size-2) && buf[i+1] == 0x07 && (buf[i+2] & 0xF0) == 0xF0) \ 40 || state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE || state == DCA_HD_MARKER) 41 42/** 43 * Find the end of the current frame in the bitstream. 44 * @return the position of the first byte of the next frame, or -1 45 */ 46static int dca_find_frame_end(DCAParseContext * pc1, const uint8_t * buf, 47 int buf_size) 48{ 49 int start_found, i; 50 uint32_t state; 51 ParseContext *pc = &pc1->pc; 52 53 start_found = pc->frame_start_found; 54 state = pc->state; 55 56 i = 0; 57 if (!start_found) { 58 for (i = 0; i < buf_size; i++) { 59 state = (state << 8) | buf[i]; 60 if (IS_MARKER(state, i, buf, buf_size)) { 61 if (!pc1->lastmarker || state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER) { 62 start_found = 1; 63 pc1->lastmarker = state; 64 i++; 65 break; 66 } 67 } 68 } 69 } 70 if (start_found) { 71 for (; i < buf_size; i++) { 72 pc1->size++; 73 state = (state << 8) | buf[i]; 74 if (state == DCA_HD_MARKER && !pc1->hd_pos) 75 pc1->hd_pos = pc1->size; 76 if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) { 77 if(pc1->framesize > pc1->size) 78 continue; 79 pc->frame_start_found = 0; 80 pc->state = -1; 81 pc1->size = 0; 82 return i - 3; 83 } 84 } 85 } 86 pc->frame_start_found = start_found; 87 pc->state = state; 88 return END_NOT_FOUND; 89} 90 91static av_cold int dca_parse_init(AVCodecParserContext * s) 92{ 93 DCAParseContext *pc1 = s->priv_data; 94 95 pc1->lastmarker = 0; 96 return 0; 97} 98 99static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration, 100 int *sample_rate, int *framesize) 101{ 102 GetBitContext gb; 103 uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 }; 104 int ret, sample_blocks, sr_code; 105 106 if (buf_size < 12) 107 return AVERROR_INVALIDDATA; 108 109 if ((ret = ff_dca_convert_bitstream(buf, 12, hdr, 12)) < 0) 110 return ret; 111 112 init_get_bits(&gb, hdr, 96); 113 114 skip_bits_long(&gb, 39); 115 sample_blocks = get_bits(&gb, 7) + 1; 116 if (sample_blocks < 8) 117 return AVERROR_INVALIDDATA; 118 *duration = 256 * (sample_blocks / 8); 119 120 *framesize = get_bits(&gb, 14) + 1; 121 if (*framesize < 95) 122 return AVERROR_INVALIDDATA; 123 124 skip_bits(&gb, 6); 125 sr_code = get_bits(&gb, 4); 126 *sample_rate = avpriv_dca_sample_rates[sr_code]; 127 if (*sample_rate == 0) 128 return AVERROR_INVALIDDATA; 129 130 return 0; 131} 132 133static int dca_parse(AVCodecParserContext * s, 134 AVCodecContext * avctx, 135 const uint8_t ** poutbuf, int *poutbuf_size, 136 const uint8_t * buf, int buf_size) 137{ 138 DCAParseContext *pc1 = s->priv_data; 139 ParseContext *pc = &pc1->pc; 140 int next, duration, sample_rate; 141 142 if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { 143 next = buf_size; 144 } else { 145 next = dca_find_frame_end(pc1, buf, buf_size); 146 147 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { 148 *poutbuf = NULL; 149 *poutbuf_size = 0; 150 return buf_size; 151 } 152 } 153 154 /* read the duration and sample rate from the frame header */ 155 if (!dca_parse_params(buf, buf_size, &duration, &sample_rate, &pc1->framesize)) { 156 s->duration = duration; 157 avctx->sample_rate = sample_rate; 158 } else 159 s->duration = 0; 160 161 *poutbuf = buf; 162 *poutbuf_size = buf_size; 163 return next; 164} 165 166AVCodecParser ff_dca_parser = { 167 .codec_ids = { AV_CODEC_ID_DTS }, 168 .priv_data_size = sizeof(DCAParseContext), 169 .parser_init = dca_parse_init, 170 .parser_parse = dca_parse, 171 .parser_close = ff_parse_close, 172}; 173