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ffmpeg
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Use pre-allocated temp buffers in mdct512(). 

5% faster in function.

Originally committed as revision 26029 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Justin Ruggles 2010-12-16 03:44:29 +00:00
parent e29065f7bf
commit c41ac4f82e
1 changed files with 40 additions and 6 deletions
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46
libavcodec/ac3enc.c
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@ -55,6 +55,12 @@ typedef struct IComplex {
int16_t re,im;
} IComplex;
typedef struct AC3MDCTContext {
AVCodecContext *avctx; ///< parent context for av_log()
int16_t *rot_tmp; ///< temp buffer for pre-rotated samples
IComplex *cplx_tmp; ///< temp buffer for complex pre-rotated samples
} AC3MDCTContext;
/**
* Data for a single audio block.
*/
@ -78,6 +84,7 @@ typedef struct AC3Block {
*/
typedef struct AC3EncodeContext {
PutBitContext pb; ///< bitstream writer context
AC3MDCTContext mdct; ///< MDCT context
AC3Block blocks[AC3_MAX_BLOCKS]; ///< per-block info
@ -189,6 +196,17 @@ static void deinterleave_input_samples(AC3EncodeContext *s,
}
/**
* Finalize MDCT and free allocated memory.
*/
static av_cold void mdct_end(AC3MDCTContext *mdct)
{
av_freep(&mdct->rot_tmp);
av_freep(&mdct->cplx_tmp);
}
/**
* Initialize FFT tables.
* @param ln log2(FFT size)
@ -213,7 +231,7 @@ static av_cold void fft_init(int ln)
* Initialize MDCT tables.
* @param nbits log2(MDCT size)
*/
static av_cold void mdct_init(int nbits)
static av_cold int mdct_init(AC3MDCTContext *mdct, int nbits)
{
int i, n, n4;
@ -222,11 +240,20 @@ static av_cold void mdct_init(int nbits)
fft_init(nbits - 2);
FF_ALLOC_OR_GOTO(mdct->avctx, mdct->rot_tmp, n * sizeof(*mdct->rot_tmp),
mdct_alloc_fail);
FF_ALLOC_OR_GOTO(mdct->avctx, mdct->cplx_tmp, n4 * sizeof(*mdct->cplx_tmp),
mdct_alloc_fail);
for (i = 0; i < n4; i++) {
float alpha = 2.0 * M_PI * (i + 1.0 / 8.0) / n;
xcos1[i] = FIX15(-cos(alpha));
xsin1[i] = FIX15(-sin(alpha));
}
return 0;
mdct_alloc_fail:
return AVERROR(ENOMEM);
}
@ -330,11 +357,11 @@ static void fft(IComplex *z, int ln)
* @param out 256 output frequency coefficients
* @param in 512 windowed input audio samples
*/
static void mdct512(int32_t *out, int16_t *in)
static void mdct512(AC3MDCTContext *mdct, int32_t *out, int16_t *in)
{
int i, re, im;
int16_t rot[MDCT_SAMPLES];
IComplex x[MDCT_SAMPLES/4];
int16_t *rot = mdct->rot_tmp;
IComplex *x = mdct->cplx_tmp;
/* shift to simplify computations */
for (i = 0; i < MDCT_SAMPLES/4; i++)
@ -448,7 +475,7 @@ static void apply_mdct(AC3EncodeContext *s)
block->exp_shift[ch] = normalize_samples(s);
mdct512(block->mdct_coef[ch], s->windowed_samples);
mdct512(&s->mdct, block->mdct_coef[ch], s->windowed_samples);
}
}
}
@ -1499,6 +1526,8 @@ static av_cold int ac3_encode_close(AVCodecContext *avctx)
av_freep(&block->qmant);
}
mdct_end(&s->mdct);
av_freep(&avctx->coded_frame);
return 0;
}
@ -1729,7 +1758,12 @@ static av_cold int ac3_encode_init(AVCodecContext *avctx)
bit_alloc_init(s);
mdct_init(9);
s->mdct.avctx = avctx;
ret = mdct_init(&s->mdct, 9);
if (ret) {
ac3_encode_close(avctx);
return ret;
}
ret = allocate_buffers(avctx);
if (ret) {