| /* |
| * DCA parser |
| * Copyright (C) 2004 Gildas Bazin |
| * Copyright (C) 2004 Benjamin Zores |
| * Copyright (C) 2006 Benjamin Larsson |
| * Copyright (C) 2007 Konstantin Shishkov |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "dca.h" |
| #include "get_bits.h" |
| #include "parser.h" |
| |
| typedef struct DCAParseContext { |
| ParseContext pc; |
| uint32_t lastmarker; |
| int size; |
| int framesize; |
| int hd_pos; |
| } DCAParseContext; |
| |
| #define IS_MARKER(state, i, buf, buf_size) \ |
| ((state == DCA_MARKER_14B_LE && (i < buf_size - 2) && (buf[i + 1] & 0xF0) == 0xF0 && buf[i + 2] == 0x07) || \ |
| (state == DCA_MARKER_14B_BE && (i < buf_size - 2) && buf[i + 1] == 0x07 && (buf[i + 2] & 0xF0) == 0xF0) || \ |
| state == DCA_MARKER_RAW_LE || state == DCA_MARKER_RAW_BE || state == DCA_HD_MARKER) |
| |
| /** |
| * Find the end of the current frame in the bitstream. |
| * @return the position of the first byte of the next frame, or -1 |
| */ |
| static int dca_find_frame_end(DCAParseContext *pc1, const uint8_t *buf, |
| int buf_size) |
| { |
| int start_found, i; |
| uint32_t state; |
| ParseContext *pc = &pc1->pc; |
| |
| start_found = pc->frame_start_found; |
| state = pc->state; |
| |
| i = 0; |
| if (!start_found) { |
| for (i = 0; i < buf_size; i++) { |
| state = (state << 8) | buf[i]; |
| if (IS_MARKER(state, i, buf, buf_size)) { |
| if (!pc1->lastmarker || state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER) { |
| start_found = 1; |
| pc1->lastmarker = state; |
| i++; |
| break; |
| } |
| } |
| } |
| } |
| if (start_found) { |
| for (; i < buf_size; i++) { |
| pc1->size++; |
| state = (state << 8) | buf[i]; |
| if (state == DCA_HD_MARKER && !pc1->hd_pos) |
| pc1->hd_pos = pc1->size; |
| if (IS_MARKER(state, i, buf, buf_size) && (state == pc1->lastmarker || pc1->lastmarker == DCA_HD_MARKER)) { |
| if (pc1->framesize > pc1->size) |
| continue; |
| pc->frame_start_found = 0; |
| pc->state = -1; |
| pc1->size = 0; |
| return i - 3; |
| } |
| } |
| } |
| pc->frame_start_found = start_found; |
| pc->state = state; |
| return END_NOT_FOUND; |
| } |
| |
| static av_cold int dca_parse_init(AVCodecParserContext *s) |
| { |
| DCAParseContext *pc1 = s->priv_data; |
| |
| pc1->lastmarker = 0; |
| return 0; |
| } |
| |
| static int dca_parse_params(const uint8_t *buf, int buf_size, int *duration, |
| int *sample_rate, int *framesize) |
| { |
| GetBitContext gb; |
| uint8_t hdr[12 + FF_INPUT_BUFFER_PADDING_SIZE] = { 0 }; |
| int ret, sample_blocks, sr_code; |
| |
| if (buf_size < 12) |
| return AVERROR_INVALIDDATA; |
| |
| if ((ret = avpriv_dca_convert_bitstream(buf, 12, hdr, 12)) < 0) |
| return ret; |
| |
| init_get_bits(&gb, hdr, 96); |
| |
| skip_bits_long(&gb, 39); |
| sample_blocks = get_bits(&gb, 7) + 1; |
| if (sample_blocks < 8) |
| return AVERROR_INVALIDDATA; |
| *duration = 256 * (sample_blocks / 8); |
| |
| *framesize = get_bits(&gb, 14) + 1; |
| if (*framesize < 95) |
| return AVERROR_INVALIDDATA; |
| |
| skip_bits(&gb, 6); |
| sr_code = get_bits(&gb, 4); |
| *sample_rate = avpriv_dca_sample_rates[sr_code]; |
| if (*sample_rate == 0) |
| return AVERROR_INVALIDDATA; |
| |
| return 0; |
| } |
| |
| static int dca_parse(AVCodecParserContext *s, AVCodecContext *avctx, |
| const uint8_t **poutbuf, int *poutbuf_size, |
| const uint8_t *buf, int buf_size) |
| { |
| DCAParseContext *pc1 = s->priv_data; |
| ParseContext *pc = &pc1->pc; |
| int next, duration, sample_rate; |
| |
| if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
| next = buf_size; |
| } else { |
| next = dca_find_frame_end(pc1, buf, buf_size); |
| |
| if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
| *poutbuf = NULL; |
| *poutbuf_size = 0; |
| return buf_size; |
| } |
| } |
| |
| /* read the duration and sample rate from the frame header */ |
| if (!dca_parse_params(buf, buf_size, &duration, &sample_rate, &pc1->framesize)) { |
| s->duration = duration; |
| avctx->sample_rate = sample_rate; |
| } else |
| s->duration = 0; |
| |
| *poutbuf = buf; |
| *poutbuf_size = buf_size; |
| return next; |
| } |
| |
| AVCodecParser ff_dca_parser = { |
| .codec_ids = { AV_CODEC_ID_DTS }, |
| .priv_data_size = sizeof(DCAParseContext), |
| .parser_init = dca_parse_init, |
| .parser_parse = dca_parse, |
| .parser_close = ff_parse_close, |
| }; |