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FFmpeg/libavcodec/wma_common.c

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/*
* common code shared by all WMA variants
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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;
}