| 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 | |
| 29 | typedef 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 | */ |
| 46 | static 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 | |
| 91 | static 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 | |
| 99 | static 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 = avpriv_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 | |
| 133 | static 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 | |
| 166 | AVCodecParser 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 | }; |