ECLDCTCompress Class Reference

ECL waveform compression/decompression to/from the BitStream storage based on the Discrete Cosine Transform (DCT) More...

#include <ECLCompress.h>

Inheritance diagram for ECLDCTCompress:

Public Member Functions
	ECLDCTCompress (double scale, double c0, width_t *w)
	Constructor for DCT based compression algorithm.
void	compress (BitStream &out, const int *adc) override
	function to compress
void	uncompress (BitStream &in, int *adc) override
	function to decompress

Protected Attributes
const double	m_scale = 0.0
	Scale factor for quantization.
const double	m_c0 = 0.0
	Average waveform amplitude.
const width_t *	m_widths = nullptr
	Bit widths for the DCT coefficients for prefix encoding.

Detailed Description

ECL waveform compression/decompression to/from the BitStream storage based on the Discrete Cosine Transform (DCT)

Definition at line 84 of file ECLCompress.h.

Constructor & Destructor Documentation

ECLDCTCompress()

ECLDCTCompress	(	double	scale,
		double	c0,
		width_t *	w )

Constructor for DCT based compression algorithm.

Parameters

scale	scale factor for quantization.
c0	average waveform amplitude.
w	DCT coefficient probability density based bit widths for quantized coefficients

Definition at line 243 of file ECLCompress.cc.

: m_scale(scale), m_c0(c0), m_widths(w) {}

Member Function Documentation

compress()

void compress ( BitStream & out, const int * adc )

overridevirtual

function to compress

Implements ECLCompress.

Definition at line 245 of file ECLCompress.cc.

{
  const int N = EclConfiguration::m_nsmp;
  double buf[N], out[N];
  for (int k = 0; k < N; k++) buf[k] = a[k];
  // cppcheck-suppress uninitvar ; buf is filled by the loop above
  e10_31(buf, out);
  for (int k = 0; k < N; k++) out[k] *= 1.0 / (2 * N);
 
  int km = N;
  for (; km > 16; --km) if (lrint(out[km - 1]*m_scale) != 0) break;
  OUT.putNBits(N - km, 4);
  out[0] -= m_c0;
  for (int k = 0; k < km; k++) {
    int t = lrint(out[k] * m_scale);
    stream_int(OUT, t, m_widths[k]);
  }
}

uncompress()

void uncompress ( BitStream & in, int * adc )

overridevirtual

function to decompress

Implements ECLCompress.

Definition at line 264 of file ECLCompress.cc.

{
  const double iscale = 1 / m_scale;
  const int N = EclConfiguration::m_nsmp;
  int nz = in.getNBits(4);
  for (int i = 0; i < N - nz; i++) adc[i] = fetch_int(in, m_widths[i]);
  for (int i = N - nz; i < N; i++) adc[i] = 0;
 
  double c[N], out[N];
  for (int k = 0; k < N; k++) c[k] = adc[k] * iscale;
  c[0] += m_c0;
 
  e01_31(c, out);
 
  for (int k = 0; k < N; k++) adc[k] = lrint(out[k]);
}

Member Data Documentation

m_c0

const double m_c0 = 0.0

protected

Average waveform amplitude.

Definition at line 102 of file ECLCompress.h.

m_scale

const double m_scale = 0.0

protected

Scale factor for quantization.

Definition at line 101 of file ECLCompress.h.

m_widths

const width_t* m_widths = nullptr

protected

Bit widths for the DCT coefficients for prefix encoding.

Definition at line 103 of file ECLCompress.h.

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The documentation for this class was generated from the following files:

• ecl/digitization/include/ECLCompress.h
• ecl/digitization/src/ECLCompress.cc