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Added resampling filter coefficients as in ITU-T Rec. P863 and ETSI TR 103 138 #195

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Added resampling filter coefficients as in ITU-T Rec. P863 and ETSI TR 103 138 #195

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1510d46
added resampling filter coefficents as used in ITU-T Rec. P863 and pu…
Jun 11, 2026
7fd2d22
Add P.863/P.863.2 resampling filters (factors 2, 3, 4, 6)
Jun 11, 2026
1ab80d0
Merge pull request #2 from ludomal/PR_195
annallag Jun 12, 2026
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2 changes: 2 additions & 0 deletions doc/g191.md
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Expand Up @@ -26,6 +26,8 @@ This edition introduces changes to Annex A, which describes the ITU-T Software T

* SHQ2/SHQ3 half-band and HP50 high-pass FIR filters

* P.863/P.863.2 resampling FIR filters for rate-change factors 2, 3, 4 and 6 (as published in ETSI TR 103 138)

* Cross-platform portability fixes with expanded CTest regression coverage

Recommendation ITU-T G.191 includes an electronic attachment containing STL2026 and manual.
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8 changes: 8 additions & 0 deletions doc/g191_Annex_A.md
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Expand Up @@ -94,6 +94,14 @@ The functions included are as follows:
| `shq_down_3_to_1_init` | initialize 3:1 SHQ down-sampling filter. |
| `hp50_32khz_init` | initialize 50-Hz high-pass filter (32-kHz sampling). |
| `hp50_48khz_init` | initialize 50-Hz high-pass filter (48-kHz sampling). |
| `p863_up_1_to_2_init` | initialize P.863/P.863.2 resampling 1:2 up-sampling filter (256 taps). |
| `p863_down_2_to_1_init` | initialize P.863/P.863.2 resampling 2:1 down-sampling filter (256 taps). |
| `p863_up_1_to_3_init` | initialize P.863/P.863.2 resampling 1:3 up-sampling filter (384 taps). |
| `p863_down_3_to_1_init` | initialize P.863/P.863.2 resampling 3:1 down-sampling filter (384 taps). |
| `p863_up_1_to_4_init` | initialize P.863/P.863.2 resampling 1:4 up-sampling filter (512 taps). |
| `p863_down_4_to_1_init` | initialize P.863/P.863.2 resampling 4:1 down-sampling filter (512 taps). |
| `p863_up_1_to_6_init` | initialize P.863/P.863.2 resampling 1:6 up-sampling filter (768 taps). |
| `p863_down_6_to_1_init` | initialize P.863/P.863.2 resampling 6:1 down-sampling filter (768 taps). |
| `hq_kernel` | FIR filtering function. |
| `hq_reset` | clear state variables. |
| `hq_free` | deallocate FIR-filter memory. |
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50 changes: 50 additions & 0 deletions doc/manual/rate.tex
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Expand Up @@ -550,6 +550,8 @@ \subsection{FIR module}

High-pass filters with 50 Hz cutoff frequency (3\,dB point) for the 32 and 48 kHz sampling rates (HP50\_32K with 1119 coefficients and HP50\_48K with 1679 coefficients) are also provided. Their frequency response is given in figure \ref{hp50}.

Resampling filters as used in ITU-T Rec.\ P.863 (POLQA) and ITU-T Rec.\ P.863.2 (PAMD), also published in ETSI TR~103~138, are provided for rate-change factors 2, 3, 4 and~6 (with 256, 384, 512 and 768 taps, respectively). These filters use a normalized cutoff frequency of~0.475 and are intended for standardized resampling of speech signals between sampling rates of 8, 16 and~48~kHz.

Since the digital filters have memory, state variables are needed. In
this version of the STL, a type {\tt SCD\_FIR} is defined, containing the past
sample memory, as well as filter coefficients and other control
Expand Down Expand Up @@ -1245,6 +1247,14 @@ \subsection{FIR module}
SCD\_FIR *LP12\_48kHz\_init (void);\\
SCD\_FIR *LP14\_48kHz\_init (void);\\
SCD\_FIR *L20\_48kHz\_init (void);\\
SCD\_FIR *p863\_up\_1\_to\_2\_init (void);\\
SCD\_FIR *p863\_down\_2\_to\_1\_init (void);\\
SCD\_FIR *p863\_up\_1\_to\_3\_init (void);\\
SCD\_FIR *p863\_down\_3\_to\_1\_init (void);\\
SCD\_FIR *p863\_up\_1\_to\_4\_init (void);\\
SCD\_FIR *p863\_down\_4\_to\_1\_init (void);\\
SCD\_FIR *p863\_up\_1\_to\_6\_init (void);\\
SCD\_FIR *p863\_down\_6\_to\_1\_init (void);\\
}


Expand Down Expand Up @@ -1463,6 +1473,46 @@ \subsection{FIR module}
point for this filter is located at approximately 20000 Hz. Code is
in file {\tt fir-LP.c}.

{\tt p863\_up\_1\_to\_2\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR up-sampling filter by a factor of~2
(256~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_down\_2\_to\_1\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR down-sampling filter by a factor of~2
(256~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_up\_1\_to\_3\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR up-sampling filter by a factor of~3
(384~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_down\_3\_to\_1\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR down-sampling filter by a factor of~3
(384~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_up\_1\_to\_4\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR up-sampling filter by a factor of~4
(512~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_down\_4\_to\_1\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR down-sampling filter by a factor of~4
(512~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_up\_1\_to\_6\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR up-sampling filter by a factor of~6
(768~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.

{\tt p863\_down\_6\_to\_1\_init} is the initialization routine for the
P.863/P.863.2 resampling FIR down-sampling filter by a factor of~6
(768~taps, normalized cutoff frequency 0.475). Code is in file {\tt
fir-resamp.c}.


\rulex{1mm}

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63 changes: 60 additions & 3 deletions src/fir/CMakeLists.txt
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Expand Up @@ -2,13 +2,13 @@ include_directories(../iir)
include_directories(../utl)


add_executable(filter filter.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c ../utl/ugst-utl.c ../utl/wav_io.c)
add_executable(filter filter.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c fir-resamp.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c ../utl/ugst-utl.c ../utl/wav_io.c)
target_link_libraries(filter ${M_LIBRARY})

add_executable(flt fltresp.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c)
add_executable(flt fltresp.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c fir-resamp.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c)
target_link_libraries(flt ${M_LIBRARY})

add_executable(firdemo firdemo.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c ../utl/ugst-utl.c ../utl/wav_io.c)
add_executable(firdemo firdemo.c fir-dsm.c fir-flat.c fir-irs.c fir-lib.c fir-pso.c fir-tia.c fir-hirs.c fir-wb.c fir-msin.c fir-LP.c fir-resamp.c ../iir/iir-lib.c ../iir/iir-g712.c ../iir/iir-dir.c ../iir/iir-flat.c ../utl/ugst-utl.c ../utl/wav_io.c)
target_link_libraries(firdemo ${M_LIBRARY})

#Test: FIR
Expand Down Expand Up @@ -177,3 +177,60 @@ add_test(filter30-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv

add_test(filter31 ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q HP50_48KHZ test_data/test.src test_data/test-hp50-48khz.flt)
add_test(filter31-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/test-hp50-48khz.flt test_data/test-hp50-48khz.ref)

#Test: P863 resampling filters (raw PCM)
add_test(filter-p863-48to16 ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -down P863_3 test_data/p863_48k_in.raw test_data/p863_48k_to_16k.tst)
add_test(filter-p863-48to16-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_16k.tst test_data/p863_48k_to_16k.raw)

add_test(filter-p863-48to8 ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -down P863_6 test_data/p863_48k_in.raw test_data/p863_48k_to_8k.tst)
add_test(filter-p863-48to8-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_8k.tst test_data/p863_48k_to_8k.raw)

add_test(filter-p863-8to16 ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -up P863_2 test_data/p863_8k_in.raw test_data/p863_8k_to_16k.tst)
add_test(filter-p863-8to16-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_16k.tst test_data/p863_8k_to_16k.raw)

add_test(filter-p863-8to48 ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -up P863_6 test_data/p863_8k_in.raw test_data/p863_8k_to_48k.tst)
add_test(filter-p863-8to48-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_48k.tst test_data/p863_8k_to_48k.raw)

#Test: P863 resampling filters (WAV)
add_test(filter-p863-48to16-wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -down P863_3 test_data/p863_48k_in.wav test_data/p863_48k_to_16k_tst.wav)
add_test(filter-p863-48to16-wav-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_16k_tst.wav test_data/p863_48k_to_16k.wav)

add_test(filter-p863-48to8-wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -down P863_6 test_data/p863_48k_in.wav test_data/p863_48k_to_8k_tst.wav)
add_test(filter-p863-48to8-wav-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_8k_tst.wav test_data/p863_48k_to_8k.wav)

add_test(filter-p863-8to16-wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -up P863_2 test_data/p863_8k_in.wav test_data/p863_8k_to_16k_tst.wav)
add_test(filter-p863-8to16-wav-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_16k_tst.wav test_data/p863_8k_to_16k.wav)

add_test(filter-p863-8to48-wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/filter -q -up P863_6 test_data/p863_8k_in.wav test_data/p863_8k_to_48k_tst.wav)
add_test(filter-p863-8to48-wav-verify ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_48k_tst.wav test_data/p863_8k_to_48k.wav)

set_tests_properties(
filter-p863-48to16 filter-p863-48to16-verify
filter-p863-48to8 filter-p863-48to8-verify
filter-p863-8to16 filter-p863-8to16-verify
filter-p863-8to48 filter-p863-8to48-verify
filter-p863-48to16-wav filter-p863-48to16-wav-verify
filter-p863-48to8-wav filter-p863-48to8-wav-verify
filter-p863-8to16-wav filter-p863-8to16-wav-verify
filter-p863-8to48-wav filter-p863-8to48-wav-verify
PROPERTIES WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})

#Test: P863 cross-validation (raw output vs WAV reference, WAV output vs raw reference)
add_test(filter-p863-48to16-cross-raw2wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_16k.tst test_data/p863_48k_to_16k.wav)
add_test(filter-p863-48to16-cross-wav2raw ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_16k_tst.wav test_data/p863_48k_to_16k.raw)

add_test(filter-p863-48to8-cross-raw2wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_8k.tst test_data/p863_48k_to_8k.wav)
add_test(filter-p863-48to8-cross-wav2raw ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_48k_to_8k_tst.wav test_data/p863_48k_to_8k.raw)

add_test(filter-p863-8to16-cross-raw2wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_16k.tst test_data/p863_8k_to_16k.wav)
add_test(filter-p863-8to16-cross-wav2raw ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_16k_tst.wav test_data/p863_8k_to_16k.raw)

add_test(filter-p863-8to48-cross-raw2wav ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_48k.tst test_data/p863_8k_to_48k.wav)
add_test(filter-p863-8to48-cross-wav2raw ${CMAKE_RUNTIME_OUTPUT_DIRECTORY}/signal-diff -q -equiv 1 test_data/p863_8k_to_48k_tst.wav test_data/p863_8k_to_48k.raw)

set_tests_properties(
filter-p863-48to16-cross-raw2wav filter-p863-48to16-cross-wav2raw
filter-p863-48to8-cross-raw2wav filter-p863-48to8-cross-wav2raw
filter-p863-8to16-cross-raw2wav filter-p863-8to16-cross-wav2raw
filter-p863-8to48-cross-raw2wav filter-p863-8to48-cross-wav2raw
PROPERTIES WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
40 changes: 38 additions & 2 deletions src/fir/filter.c
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Expand Up @@ -209,7 +209,11 @@ int valid_filter (char *F_type, char modified_IRS) {
// FILTER_12k48k_HW
|| strncmp (F_type, "LP12", 4) == 0 || strncmp (F_type, "lp12", 4) == 0
// FILTER_12k48k_HW
|| strncmp (F_type, "LP14", 4) == 0 || strncmp (F_type, "lp14", 4) == 0 || strncmp (F_type, "LP20", 4) == 0 || strncmp (F_type, "lp20", 4) == 0 || strncmp (F_type, "hp50_32khz", 10) == 0 || strncmp (F_type, "HP50_32KHZ", 10) == 0 || strncmp (F_type, "hp50_48khz", 10) == 0 || strncmp (F_type, "HP50_48KHZ", 10) == 0)
|| strncmp (F_type, "LP14", 4) == 0 || strncmp (F_type, "lp14", 4) == 0 || strncmp (F_type, "LP20", 4) == 0 || strncmp (F_type, "lp20", 4) == 0 || strncmp (F_type, "hp50_32khz", 10) == 0 || strncmp (F_type, "HP50_32KHZ", 10) == 0 || strncmp (F_type, "hp50_48khz", 10) == 0 || strncmp (F_type, "HP50_48KHZ", 10) == 0
|| strncmp (F_type, "p863_2", 6) == 0 || strncmp (F_type, "P863_2", 6) == 0
|| strncmp (F_type, "p863_3", 6) == 0 || strncmp (F_type, "P863_3", 6) == 0
|| strncmp (F_type, "p863_4", 6) == 0 || strncmp (F_type, "P863_4", 6) == 0
|| strncmp (F_type, "p863_6", 6) == 0 || strncmp (F_type, "P863_6", 6) == 0)
valid = 1;

/* No MOD-IRS filter at 8 kHz */
Expand Down Expand Up @@ -297,7 +301,11 @@ void display_usage () {
printf (" HP50_32KHZ 50 Hz highpass FIR filter w/ factor 1:1 at sf=32kHz, 1119 coefs\n");
printf (" HP50_48KHZ 50 Hz highpass FIR filter w/ factor 1:1 at sf=48kHz, 1679 coefs\n");
printf (" SHQ2 FIR (Super High quality : 729 coefs, -80dB) low-pass for factor 1:2 (up) or 2:1(down)\n");
printf (" SHQ3 FIR (Super High quality : 729 coefs, -80dB) low-pass for factor 1:3 (up) or 3:1(down)\n\n");
printf (" SHQ3 FIR (Super High quality : 729 coefs, -80dB) low-pass for factor 1:3 (up) or 3:1(down)\n");
printf (" P863_2 P.863/P.863.2 resampling filter for factor 1:2 (up) or 2:1 (down)\n");
printf (" P863_3 P.863/P.863.2 resampling filter for factor 1:3 (up) or 3:1 (down)\n");
printf (" P863_4 P.863/P.863.2 resampling filter for factor 1:4 (up) or 4:1 (down)\n");
printf (" P863_6 P.863/P.863.2 resampling filter for factor 1:6 (up) or 6:1 (down)\n\n");

/* Quit program */
exit (-128);
Expand Down Expand Up @@ -685,6 +693,34 @@ int main (int argc, char *argv[]) {
fir_state = hp50_48khz_init ();
}

/*
* Filter type: P863 - P.863/P.863.2 resampling filters
* P863_2: factor 1:2 (up) or 2:1 (down)
* P863_3: factor 1:3 (up) or 3:1 (down)
* P863_4: factor 1:4 (up) or 4:1 (down)
* P863_6: factor 1:6 (up) or 6:1 (down)
*/
else if (strncmp (F_type, "p863_", 5) == 0 || strncmp (F_type, "P863_", 5) == 0) {
int f = atoi (&F_type[5]);
if (upsample) {
switch (f) {
case 2: fir_state = p863_up_1_to_2_init (); break;
case 3: fir_state = p863_up_1_to_3_init (); break;
case 4: fir_state = p863_up_1_to_4_init (); break;
case 6: fir_state = p863_up_1_to_6_init (); break;
default: error_terminate ("P863: factor must be 2, 3, 4, or 6\n", 15);
}
} else {
switch (f) {
case 2: fir_state = p863_down_2_to_1_init (); break;
case 3: fir_state = p863_down_3_to_1_init (); break;
case 4: fir_state = p863_down_4_to_1_init (); break;
case 6: fir_state = p863_down_6_to_1_init (); break;
default: error_terminate ("P863: factor must be 2, 3, 4, or 6\n", 15);
}
}
}

/*
* Filter type: PCM - Standard PCM quality 2:1 or 1:2 factor:
* . fs == 8000 -> upsample: 1:2
Expand Down
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