Fix LFE low-pass filter using a hardcoded 48 kHz sample rate - #15
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The 120 Hz LFE low-pass applied when rendering HOA to an LFE-bearing loudspeaker layout computed its biquad coefficients for a hardcoded 48 kHz rate regardless of oar_config_t.sampling_rate, so the effective cutoff scaled with the output rate (~240 Hz at 96 kHz, rendering the LFE 2.7x too loud for content near the cutoff and with ~4 dB less stopband attenuation; ~110 Hz at 44.1 kHz). Plumb the context sample rate into IAMF_element_renderer_render_H2M so the lazy init uses the actual rate, and fix the eager init in ear.c, which referenced an undeclared identifier (out_info) and prevented the DISABLE_LFE_HOA=0 configuration from compiling at all. Since no build defined DISABLE_LFE_HOA, the LFE path was unreachable in every configuration; add an OAR_ENABLE_HOA_LFE CMake option (default OFF, preserving current behavior) so it can be built and tested. Adds test_hoa_lfe_rendering (built when the option is ON): renders a 1OA W-channel tone to 5.1 at 44.1/48/96 kHz through the public API and verifies the LFE level is rate-invariant (the hardcoded-48k bug fails this at 2.697x for 96 kHz) and that the low-pass attenuates a 1 kHz tone by more than 25 dB at every rate. Fixes #1.
trsonic
requested review from
felicialim,
jingbo-marquis,
trevorknight,
yeroro and
yilun-zhangs
July 27, 2026 08:01
yilun-zhangs
approved these changes
Jul 28, 2026
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Thanks @jingbo-marquis and @yilun-zhangs ! |
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Dropping these includes was correct against the base this branch started from, but the LFE filter added in #15 uses tanf(), M_PI, sqrt() and memset() in this file, so a build with -DOAR_ENABLE_HOA_LFE=ON no longer compiles without them. It also left `#define _USE_MATH_DEFINES` with no <math.h> following it, which is what that define exists for on MSVC.
trsonic
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Aug 20, 2026
#15 added the OAR_ENABLE_HOA_LFE CMake option and a test that exercises the 120 Hz LFE low-pass, neither of which the Bazel build knew about. `--define OAR_ENABLE_HOA_LFE=1` now sets DISABLE_LFE_HOA=0 on ae_rdr, whose header defaults it to 1, matching what the CMake option does globally. The test target is gated with target_compatible_with, so `bazel build //...` skips it instead of building a test whose subject was compiled out.
trsonic
added a commit
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Aug 20, 2026
Dropping these includes was correct against the base this branch started from, but the LFE filter added in #15 uses tanf(), M_PI, sqrt() and memset() in this file, so a build with -DOAR_ENABLE_HOA_LFE=ON no longer compiles without them. It also left `#define _USE_MATH_DEFINES` with no <math.h> following it, which is what that define exists for on MSVC.
trsonic
added a commit
that referenced
this pull request
Aug 20, 2026
#15 added the OAR_ENABLE_HOA_LFE CMake option and a test that exercises the 120 Hz LFE low-pass, neither of which the Bazel build knew about. `--define OAR_ENABLE_HOA_LFE=1` now sets DISABLE_LFE_HOA=0 on ae_rdr, whose header defaults it to 1, matching what the CMake option does globally. The test target is gated with target_compatible_with, so `bazel build //...` skips it instead of building a test whose subject was compiled out.
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The 120 Hz LFE low-pass applied when rendering HOA to an LFE-bearing loudspeaker layout computed its biquad coefficients for a hardcoded 48 kHz rate (
DEFAULT_SAMPLERATEinh2m_rdr.c) regardless ofoar_config_t.sampling_rate. The effective cutoff therefore scaled with the output rate: ~240 Hz at 96 kHz (LFE ~2.7× too loud for content near the cutoff, with ~4 dB less stopband attenuation) and ~110 Hz at 44.1 kHz.Changes:
IAMF_element_renderer_render_H2Mso the lazy filter init uses the actual rate.ear.c, which referenced an undeclared identifier (out_info) and prevented theDISABLE_LFE_HOA=0configuration from compiling at all.DISABLE_LFE_HOA, the LFE path was unreachable in every configuration; add anOAR_ENABLE_HOA_LFECMake option (default OFF, preserving current behavior) so it can be built and tested.Testing
New
test_hoa_lfe_rendering(built when the option is ON) renders a 1OA W-channel tone to 5.1 at 44.1/48/96 kHz through the public API and verifies:Default builds (option OFF) are unchanged.