aac5773f
 hucm
功能基本完成，接口待打磨
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/*
* common code shared by all WMA variants
*
* 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 "libavutil/attributes.h"
#include "wma_common.h"
/**
*@brief Get the samples per frame for this stream.
*@param sample_rate output sample_rate
*@param version wma version
*@param decode_flags codec compression features
*@return log2 of the number of output samples per frame
*/
av_cold int ff_wma_get_frame_len_bits(int sample_rate, int version,
unsigned int decode_flags)
{
int frame_len_bits;
if (sample_rate <= 16000)
frame_len_bits = 9;
else if (sample_rate <= 22050 || (sample_rate <= 32000 && version == 1))
frame_len_bits = 10;
else if (sample_rate <= 48000 || version < 3)
frame_len_bits = 11;
else if (sample_rate <= 96000)
frame_len_bits = 12;
else
frame_len_bits = 13;
if (version == 3) {
int tmp = decode_flags & 0x6;
if (tmp == 0x2)
++frame_len_bits;
else if (tmp == 0x4)
--frame_len_bits;
else if (tmp == 0x6)
frame_len_bits -= 2;
}
return frame_len_bits;
}
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