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cosmetics: Define AC3_WINDOW_SIZE and use it instead of AC3_BLOCK_SIZE*2.

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Originally committed as revision 25951 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-14 14:50:40 +00:00
parent 7066cc8f2b
commit 1fda2c10f6
2 changed files with 5 additions and 4 deletions
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1
libavcodec/ac3.h
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@ -36,6 +36,7 @@
#define AC3_BLOCK_SIZE 256
#define AC3_MAX_BLOCKS 6
#define AC3_FRAME_SIZE (AC3_MAX_BLOCKS * 256)
#define AC3_WINDOW_SIZE (AC3_BLOCK_SIZE * 2)
/* exponent encoding strategy */
#define EXP_REUSE 0

8
libavcodec/ac3enc.c
View File

@ -1187,7 +1187,7 @@ static int AC3_encode_frame(AVCodecContext *avctx,
AC3EncodeContext *s = avctx->priv_data;
const int16_t *samples = data;
int i, j, k, v, ch;
int16_t input_samples[AC3_BLOCK_SIZE*2];
int16_t input_samples[AC3_WINDOW_SIZE];
int32_t mdct_coef[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
uint8_t exp[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][AC3_MAX_COEFS];
uint8_t exp_strategy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS];
@ -1219,17 +1219,17 @@ static int AC3_encode_frame(AVCodecContext *avctx,
for(j=0;j<AC3_BLOCK_SIZE;j++) {
input_samples[j] = MUL16(input_samples[j],
ff_ac3_window[j]) >> 15;
input_samples[AC3_BLOCK_SIZE*2-j-1] = MUL16(input_samples[AC3_BLOCK_SIZE*2-j-1],
input_samples[AC3_WINDOW_SIZE-j-1] = MUL16(input_samples[AC3_WINDOW_SIZE-j-1],
ff_ac3_window[j]) >> 15;
}
/* Normalize the samples to use the maximum available
precision */
v = 14 - log2_tab(input_samples, AC3_BLOCK_SIZE*2);
v = 14 - log2_tab(input_samples, AC3_WINDOW_SIZE);
if (v < 0)
v = 0;
exp_samples[i][ch] = v - 9;
lshift_tab(input_samples, AC3_BLOCK_SIZE*2, v);
lshift_tab(input_samples, AC3_WINDOW_SIZE, v);
/* do the MDCT */
mdct512(mdct_coef[i][ch], input_samples);