mirror of
https://github.com/FFmpeg/FFmpeg.git
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77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include <stddef.h>
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#include <stdint.h>
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#include "atsc_a53.h"
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#include "get_bits.h"
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int ff_parse_a53_cc(AVBufferRef **pbuf, const uint8_t *data, int size)
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{
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AVBufferRef *buf = *pbuf;
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GetBitContext gb;
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size_t new_size, old_size = buf ? buf->size : 0;
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int ret, cc_count;
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if (size < 3)
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return AVERROR(EINVAL);
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ret = init_get_bits8(&gb, data, size);
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if (ret < 0)
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return ret;
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if (get_bits(&gb, 8) != 0x3) // user_data_type_code
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return 0;
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skip_bits(&gb, 1); // reserved
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if (!get_bits(&gb, 1)) // process_cc_data_flag
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return 0;
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skip_bits(&gb, 1); // zero bit
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cc_count = get_bits(&gb, 5);
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if (!cc_count)
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return 0;
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skip_bits(&gb, 8); // reserved
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/* 3 bytes per CC plus one byte marker_bits at the end */
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if (cc_count * 3 >= (get_bits_left(&gb) >> 3))
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return AVERROR(EINVAL);
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new_size = (old_size + cc_count * 3);
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if (new_size > INT_MAX)
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return AVERROR(EINVAL);
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/* Allow merging of the cc data from two fields. */
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ret = av_buffer_realloc(pbuf, new_size);
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if (ret < 0)
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return ret;
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buf = *pbuf;
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/* Use of av_buffer_realloc assumes buffer is writeable */
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for (int i = 0; i < cc_count; i++) {
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buf->data[old_size++] = get_bits(&gb, 8);
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buf->data[old_size++] = get_bits(&gb, 8);
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buf->data[old_size++] = get_bits(&gb, 8);
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}
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return cc_count;
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}
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