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/*
* WMA compatible codec
* Copyright (c) 2002-2007 The FFmpeg Project
*
* 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 "wma.h"
#include "codeclib.h" /* needed for av_log2() */
/**
*@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
*/
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) {
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;
}
/**
* Decode an uncompressed coefficient.
* @param s codec context
* @return the decoded coefficient
*/
unsigned int ff_wma_get_large_val(GetBitContext* gb)
{
/** consumes up to 34 bits */
int n_bits = 8;
/** decode length */
if (get_bits1(gb)) {
n_bits += 8;
if (get_bits1(gb)) {
n_bits += 8;
if (get_bits1(gb)) {
n_bits += 7;
}
}
}
return get_bits_long(gb, n_bits);
}
/**
* Decode run level compressed coefficients.
* @param avctx codec context
* @param gb bitstream reader context
* @param vlc vlc table for get_vlc2
* @param level_table level codes
* @param run_table run codes
* @param version 0 for wma1,2 1 for wmapro
* @param ptr output buffer
* @param offset offset in the output buffer
* @param num_coefs number of input coefficents
* @param block_len input buffer length (2^n)
* @param frame_len_bits number of bits for escaped run codes
* @param coef_nb_bits number of bits for escaped level codes
* @return 0 on success, -1 otherwise
*/
#define av_log(...)
int ff_wma_run_level_decode(GetBitContext* gb,
VLC *vlc,
const int32_t *level_table, const uint16_t *run_table,
int version, int32_t *ptr, int offset,
int num_coefs, int block_len, int frame_len_bits,
int coef_nb_bits)
{
int32_t code, level, sign;
const unsigned int coef_mask = block_len - 1;
/* Rockbox: To be able to use rockbox' optimized mdct we need to pre-shift
* the values by >>(nbits-3). */
const int nbits = av_log2(block_len)+1;
const int shift = WMAPRO_FRACT-(nbits-3);
for (; offset < num_coefs; offset++) {
code = get_vlc2(gb, vlc->table, VLCBITS, VLCMAX);
if (code > 1) {
/** normal code */
offset += run_table[code];
sign = !get_bits1(gb);
/* Rockbox: To be able to use rockbox' optimized mdct we need
* invert the sign. */
ptr[offset & coef_mask] = sign ? level_table[code] : -level_table[code];
ptr[offset & coef_mask] <<= shift;
} else if (code == 1) {
/** EOB */
break;
} else {
/** escape */
if (!version) {
level = get_bits(gb, coef_nb_bits);
/** NOTE: this is rather suboptimal. reading
block_len_bits would be better */
offset += get_bits(gb, frame_len_bits);
} else {
level = ff_wma_get_large_val(gb);
/** escape decode */
if (get_bits1(gb)) {
if (get_bits1(gb)) {
if (get_bits1(gb)) {
av_log(avctx,AV_LOG_ERROR,
"broken escape sequence\n");
return -1;
} else
offset += get_bits(gb, frame_len_bits) + 4;
} else
offset += get_bits(gb, 2) + 1;
}
}
sign = !get_bits1(gb);
ptr[offset & coef_mask] = sign ? level : -level;
ptr[offset & coef_mask] <<= shift;
}
}
/** NOTE: EOB can be omitted */
if (offset > num_coefs) {
av_log(avctx, AV_LOG_ERROR, "overflow in spectral RLE, ignoring\n");
return -1;
}
return 0;
}
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