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Factorize duplicated code in at1_imdct_block() 

Originally committed as revision 20019 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Vitor Sessak 2009-09-24 21:24:58 +00:00
parent fbec307f6c
commit b11d40d12e
1 changed files with 17 additions and 18 deletions
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35
libavcodec/atrac1.c
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@ -108,6 +108,9 @@ static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
unsigned int start_pos, ref_pos = 0, pos = 0;
for (band_num = 0; band_num < AT1_QMF_BANDS; band_num++) {
float *prev_buf;
int j;
band_samples = samples_per_band[band_num];
log2_block_count = su->log2_block_count[band_num];
@ -115,6 +118,7 @@ static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
/* 4 for short mode(low/middle bands) and 8 for short mode(high band)*/
num_blocks = 1 << log2_block_count;
if (num_blocks == 1) {
/* mdct block size in samples: 128 (long mode, low & mid bands), */
/* 256 (long mode, high band) and 32 (short mode, all bands) */
block_size = band_samples >> log2_block_count;
@ -124,33 +128,28 @@ static int at1_imdct_block(AT1SUCtx* su, AT1Ctx *q)
if (nbits != 5 && nbits != 7 && nbits != 8)
return -1;
if (num_blocks == 1) {
/* long blocks */
at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos], nbits, band_num);
pos += block_size; // move to the next mdct block in the spectrum
/* overlap and window long blocks */
q->dsp.vector_fmul_window(q->bands[band_num], &su->spectrum[1][ref_pos + band_samples - 16],
&su->spectrum[0][ref_pos], ff_sine_32, 0, 16);
memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
} else {
/* short blocks */
float *prev_buf;
block_size = 32;
nbits = 5;
}
start_pos = 0;
prev_buf = &su->spectrum[1][ref_pos + band_samples - 16];
for (; num_blocks != 0; num_blocks--) {
at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], 5, band_num);
for (j=0; j < num_blocks; j++) {
at1_imdct(q, &q->spec[pos], &su->spectrum[0][ref_pos + start_pos], nbits, band_num);
/* overlap and window between short blocks */
/* overlap and window */
q->dsp.vector_fmul_window(&q->bands[band_num][start_pos], prev_buf,
&su->spectrum[0][ref_pos + start_pos], ff_sine_32, 0, 16);
prev_buf = &su->spectrum[0][ref_pos+start_pos + 16];
start_pos += 32; // use hardcoded block_size
pos += 32;
start_pos += block_size;
pos += block_size;
}
}
if (num_blocks == 1)
memcpy(q->bands[band_num] + 32, &su->spectrum[0][ref_pos + 16], 240 * sizeof(float));
ref_pos += band_samples;
}