import dsd2pcm_src.zip

[this is the code from dsd2pcm_src.zip, published on a forum by
Sebastian Gesemann.  Upon request, he has given permission to
redistribute and modify his code, without referring to a specific
license. - mk]

1 files changed, 120 insertions, 0 deletions

diff --git a/src/dsd2pcm/main.cpp b/src/dsd2pcm/main.cpp
new file mode 100644
index 000000000..0b58888a8
--- /dev/null
+++ b/src/dsd2pcm/main.cpp
@@ -0,0 +1,120 @@
+#include <iostream>
+#include <vector>
+#include <cstring>
+
+#include "dsd2pcm.hpp"
+#include "noiseshape.hpp"
+
+namespace {
+
+const float my_ns_coeffs[] = {
+//     b1           b2           a1           a2
+  -1.62666423,  0.79410094,  0.61367127,  0.23311013,  // section 1
+  -1.44870017,  0.54196219,  0.03373857,  0.70316556   // section 2
+};
+
+const int my_ns_soscount = sizeof(my_ns_coeffs)/(sizeof(my_ns_coeffs[0])*4);
+
+inline long myround(float x)
+{
+	return static_cast<long>(x + (x>=0 ? 0.5f : -0.5f));
+}
+
+template<typename T>
+struct id { typedef T type; };
+
+template<typename T>
+inline T clip(
+	typename id<T>::type min,
+	T v,
+	typename id<T>::type max)
+{
+	if (v<min) return min;
+	if (v>max) return max;
+	return v;
+}
+
+inline void write_intel16(unsigned char * ptr, unsigned word)
+{
+	ptr[0] =  word       & 0xFF;
+	ptr[1] = (word >> 8) & 0xFF;
+}
+
+inline void write_intel24(unsigned char * ptr, unsigned long word)
+{
+	ptr[0] =  word        & 0xFF;
+	ptr[1] = (word >>  8) & 0xFF;
+	ptr[2] = (word >> 16) & 0xFF;
+}
+
+} // anonymous namespace
+
+using std::vector;
+using std::cin;
+using std::cout;
+using std::cerr;
+
+int main(int argc, char *argv[])
+{
+	const int block = 16384;
+	int channels   = -1;
+	int lsbitfirst = -1;
+	int bits       = -1;
+	if (argc==4) {
+		if ('1'<=argv[1][0] && argv[1][0]<='9') channels = 1 + (argv[1][0]-'1');
+		if (argv[2][0]=='m' || argv[2][0]=='M') lsbitfirst=0;
+		if (argv[2][0]=='l' || argv[2][0]=='L') lsbitfirst=1;
+		if (!strcmp(argv[3],"16")) bits = 16;
+		if (!strcmp(argv[3],"24")) bits = 24;
+	}
+	if (channels<1 || lsbitfirst<0 || bits<0) {
+		cerr << "\n"
+			"DSD2PCM filter (raw DSD64 --> 352 kHz raw PCM)\n"
+			"(c) 2009 Sebastian Gesemann\n\n"
+			"(filter as in \"reads data from stdin and writes to stdout\")\n\n"
+			"Syntax: dsd2pcm <channels> <bitorder> <bitdepth>\n"
+			"channels = 1,2,3,...,9 (number of channels in DSD stream)\n"
+			"bitorder = L (lsb first), M (msb first) (DSD stream option)\n"
+			"bitdepth = 16 or 24 (intel byte order, output option)\n\n"
+			"Note: At 16 bits/sample a noise shaper kicks in that can preserve\n"
+			"a dynamic range of 135 dB below 30 kHz.\n\n";
+		return 1;
+	}
+	int bytespersample = bits/8;
+	vector<dxd> dxds (channels);
+	vector<noise_shaper> ns;
+	if (bits==16) {
+		ns.resize(channels, noise_shaper(my_ns_soscount, my_ns_coeffs) );
+	}
+	vector<unsigned char> dsd_data (block * channels);
+	vector<float> float_data (block);
+	vector<unsigned char> pcm_data (block * channels * bytespersample);
+	char * const dsd_in  = reinterpret_cast<char*>(&dsd_data[0]);
+	char * const pcm_out = reinterpret_cast<char*>(&pcm_data[0]);
+	while (cin.read(dsd_in,block * channels)) {
+		for (int c=0; c<channels; ++c) {
+			dxds[c].translate(block,&dsd_data[0]+c,channels,
+				lsbitfirst,
+				&float_data[0],1);
+			unsigned char * out = &pcm_data[0] + c*bytespersample;
+			if (bits==16) {
+				for (int s=0; s<block; ++s) {
+					float r = float_data[s]*32768 + ns[c].get();
+					long smp = clip(-32768,myround(r),32767);
+					ns[c].update( clip(-1,smp-r,1) );
+					write_intel16(out,smp);
+					out += channels*bytespersample;
+				}
+			} else {
+				for (int s=0; s<block; ++s) {
+					float r = float_data[s]*8388608;
+					long smp = clip(-8388608,myround(r),8388607);
+					write_intel24(out,smp);
+					out += channels*bytespersample;
+				}
+			}
+		}
+		cout.write(pcm_out,block*channels*bytespersample);
+	}
+}
+