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Cleanup and comment

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git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@4790 b3059339-0415-0410-9bf9-f77b7e298cf2
This commit is contained in:
anders 2002-02-21 16:05:09 +00:00
parent ee2ed8567e
commit 2eb3f24dc1
2 changed files with 33 additions and 34 deletions
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43
libao2/fir.h
View File

@ -11,14 +11,13 @@
#ifndef __FIR_H__
#define __FIR_H__
/* Fixpoint 16 bit fir filter FIR filter. The filter is implemented
both in C and MMX assembly. The filter consists of one macro
UPDATE_QUE and one inline function firn. The macro can be used for
adding new data to the circular buffer used by the filter firn.
Limitations: max length of n = 16*4 and n must be multiple of 4 (pad
fiter with zeros for other lengths). Sometimes it works with filters
longer than 4*16 (the problem is overshoot and the acumulated energy
in the filter taps). */
/* Fixpoint 16 bit FIR filter. The filter is implemented both in C and
MMX assembly. The filter consists of the two inline functions updateq
and firn, update q is used for adding new data to the circular buffer
used by the filter firn. Limitations: max length of n = 16*4 and n
must be multiple of 4 (pad fiter with zeros for other lengths).
Sometimes it works with filters longer than 4*16 (the problem is
overshoot and the acumulated energy in the filter taps). */
#ifdef HAVE_MMX
inline int32_t firn(int16_t* x, int16_t* w, int16_t n)
@ -60,26 +59,14 @@ inline int32_t firn(int16_t* x, int16_t* w, int16_t n)
#endif /* HAVE_MMX */
// Macro to add new data to circular queue
#define UPDATE_QUE(ind,xq,xid) \
xid=(--xid)&(L-1); \
xq[xid]=xq[xid+L]=*(ind);
#ifdef L8
#ifdef HAVE_MMX
#define FIR(x,w,y) *y=(int16_t)firn(x,w,8);
#else /* HAVE_MMX */
// Unrolled loop to speed up execution
#define FIR(x,w,y){ \
int16_t a = (w[0]*x[0]+w[1]*x[1]+w[2]*x[2]+w[3]*x[3]) >> 16; \
int16_t b = (w[4]*x[4]+w[5]*x[5]+w[6]*x[6]+w[7]*x[7]) >> 16; \
y[0] = a+b; \
/* Add new data to circular queue designed to be used with a FIR
filter. xq is the circular queue, in pointing at the new sample, xi
current index for in xq and l the lenght of the filter */
inline uint16_t updateq(int16_t* xq, int16_t* in, uint16_t xi, uint16_t l)
{
xq[xi]=xq[xi+l]=*in;
return (--xi)&(l-1); \
}
#endif /* HAVE_MMX */
#endif /* L8 */
#ifdef L16
#define FIR(x,w,y) *y=(int16_t)firn(x,w,16);
#endif /* L16 */
#endif /* __FIR_H__ */

24
libao2/pl_resample.c
View File

@ -48,13 +48,26 @@ LIBAO_PLUGIN_EXTERN(resample)
*/
#if !defined(HAVE_SSE) && !defined(HAVE_3DNOW) //This machine is slow
#define L8 1 // Filter bank type
#define W W8 // Filter bank parameters
#define L 8 // Filter length
#else // Fat machine
#define L16 1
#ifdef HAVE_MMX
#define FIR(x,w,y) *y=(int16_t)firn(x,w,8);
#else /* HAVE_MMX */
// Unrolled loop to speed up execution
#define FIR(x,w,y){ \
int16_t a = (w[0]*x[0]+w[1]*x[1]+w[2]*x[2]+w[3]*x[3]) >> 16; \
int16_t b = (w[4]*x[4]+w[5]*x[5]+w[6]*x[6]+w[7]*x[7]) >> 16; \
y[0] = a+b; \
}
#endif /* HAVE_MMX */
#else /* Fast machine */
#define W W16
#define L 16
#define FIR(x,w,y) *y=(int16_t)firn(x,w,16);
#endif
#define CH 6 // Max number of channels
@ -192,7 +205,7 @@ int upsample(){
register uint16_t i = inc;
if(wi<level) i++;
UPDATE_QUE(in,x,xi);
xi=updateq(x,in,xi,L);
in+=nch;
while(i--){
// Run the FIR filter
@ -242,9 +255,8 @@ int downsample(){
while(in < end){
UPDATE_QUE(in,x,xi);
xi=updateq(x,in,xi,L);
in+=nch;
if(!--i){
// Run the FIR filter
FIR((&x[xi]),(&pl_resample.w[wi*L]),out);