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simplify & optimize things a little 

Originally committed as revision 5516 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-06-24 13:56:29 +00:00
parent aeb2904eba
commit d1015e88b4
1 changed files with 27 additions and 48 deletions
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75
libavcodec/flacenc.c
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@ -82,10 +82,6 @@ static const int flac_blocksizes[16] = {
256, 512, 1024, 2048, 4096, 8192, 16384, 32768
};
static const int flac_blocksizes_ordered[14] = {
0, 192, 256, 512, 576, 1024, 1152, 2048, 2304, 4096, 4608, 8192, 16384, 32768
};
/**
* Writes streaminfo metadata block to byte array
*/
@ -122,17 +118,13 @@ static int select_blocksize(int samplerate)
int blocksize;
assert(samplerate > 0);
blocksize = 0;
blocksize = flac_blocksizes[1];
target = (samplerate * BLOCK_TIME_MS) / 1000;
for(i=13; i>=0; i--) {
if(target >= flac_blocksizes_ordered[i]) {
blocksize = flac_blocksizes_ordered[i];
break;
for(i=0; i<16; i++) {
if(target >= flac_blocksizes[i] && flac_blocksizes[i] > blocksize) {
blocksize = flac_blocksizes[i];
}
}
if(blocksize == 0) {
blocksize = flac_blocksizes_ordered[1];
}
return blocksize;
}
@ -144,10 +136,6 @@ static int flac_encode_init(AVCodecContext *avctx)
int i;
uint8_t *streaminfo;
if(s == NULL) {
return -1;
}
if(avctx->sample_fmt != SAMPLE_FMT_S16) {
return -1;
}
@ -282,26 +270,26 @@ static void encode_residual_verbatim(FlacEncodeContext *s, int ch)
static void encode_residual_fixed(int32_t *res, int32_t *smp, int n, int order)
{
int i;
int32_t pred;
for(i=0; i<order; i++) {
res[i] = smp[i];
}
for(i=order; i<n; i++) {
pred = 0;
switch(order) {
case 0: pred = 0;
break;
case 1: pred = smp[i-1];
break;
case 2: pred = 2*smp[i-1] - smp[i-2];
break;
case 3: pred = 3*smp[i-1] - 3*smp[i-2] + smp[i-3];
break;
case 4: pred = 4*smp[i-1] - 6*smp[i-2] + 4*smp[i-3] - smp[i-4];
break;
}
res[i] = smp[i] - pred;
if(order==0){
for(i=order; i<n; i++)
res[i]= smp[i];
}else if(order==1){
for(i=order; i<n; i++)
res[i]= smp[i] - smp[i-1];
}else if(order==2){
for(i=order; i<n; i++)
res[i]= smp[i] - 2*smp[i-1] + smp[i-2];
}else if(order==3){
for(i=order; i<n; i++)
res[i]= smp[i] - 3*smp[i-1] + 3*smp[i-2] - smp[i-3];
}else{
for(i=order; i<n; i++)
res[i]= smp[i] - 4*smp[i-1] + 6*smp[i-2] - 4*smp[i-3] + smp[i-4];
}
}
@ -328,34 +316,25 @@ static void encode_residual(FlacEncodeContext *s, int ch)
static void
put_sbits(PutBitContext *pb, int bits, int32_t val)
{
uint32_t uval;
assert(bits >= 0 && bits <= 31);
uval = (val < 0) ? (1UL << bits) + val : val;
put_bits(pb, bits, uval);
put_bits(pb, bits, val & ((1<<bits)-1));
}
static void
write_utf8(PutBitContext *pb, uint32_t val)
{
int i, bytes, mask, shift;
int bytes, shift;
bytes = 1;
if(val >= 0x80) bytes++;
if(val >= 0x800) bytes++;
if(val >= 0x10000) bytes++;
if(val >= 0x200000) bytes++;
if(val >= 0x4000000) bytes++;
if(bytes == 1) {
if(val < 0x80){
put_bits(pb, 8, val);
return;
}
bytes= (av_log2(val)-1) / 5;
shift = (bytes - 1) * 6;
mask = 0x80 + ((1 << 7) - (1 << (8 - bytes)));
put_bits(pb, 8, mask | (val >> shift));
for(i=0; i<bytes-1; i++) {
put_bits(pb, 8, (256 - (256>>bytes)) | (val >> shift));
while(shift >= 6){
shift -= 6;
put_bits(pb, 8, 0x80 | ((val >> shift) & 0x3F));
}