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Split out initialization of MDCT tables into a separate function. 

Originally committed as revision 25954 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 14:50:54 +00:00
parent 0796546370
commit a8d2b06b7c
1 changed files with 17 additions and 8 deletions
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25
libavcodec/ac3enc.c
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@ -115,6 +115,22 @@ static av_cold void fft_init(int ln)
}
}
static av_cold void mdct_init(int nbits)
{
int i;
float alpha;
int n = 1 << nbits;
int n4 = n >> 2;
fft_init(nbits - 2);
for(i=0;i<n4;i++) {
alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;
xcos1[i] = fix15(-cos(alpha));
xsin1[i] = fix15(-sin(alpha));
}
}
/* butter fly op */
#define BF(pre, pim, qre, qim, pre1, pim1, qre1, qim1) \
{\
@ -637,7 +653,6 @@ static av_cold int AC3_encode_init(AVCodecContext *avctx)
int bitrate = avctx->bit_rate;
AC3EncodeContext *s = avctx->priv_data;
int i, j, ch;
float alpha;
int bw_code;
avctx->frame_size = AC3_FRAME_SIZE;
@ -705,13 +720,7 @@ static av_cold int AC3_encode_init(AVCodecContext *avctx)
/* initial snr offset */
s->coarse_snr_offset = 40;
/* mdct init */
fft_init(MDCT_NBITS - 2);
for(i=0;i<MDCT_SAMPLES/4;i++) {
alpha = 2 * M_PI * (i + 1.0 / 8.0) / (float)MDCT_SAMPLES;
xcos1[i] = fix15(-cos(alpha));
xsin1[i] = fix15(-sin(alpha));
}
mdct_init(9);
avctx->coded_frame= avcodec_alloc_frame();
avctx->coded_frame->key_frame= 1;