diff --git a/BUILD.gn b/BUILD.gn
new file mode 100644
index 0000000..e6be4a3
--- /dev/null
+++ b/BUILD.gn
@@ -0,0 +1,372 @@
+# Copyright 2020 The Fuchsia Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import("//build/config/arm.gni")
+
+# If fixed point implementation shall be used (otherwise float).
+use_opus_fixed_point = current_cpu == "arm64"
+
+use_opus_x86_optimization = current_cpu == "x64"
+
+config("opus_config") {
+  include_dirs = [ "include" ]
+
+  if (use_opus_fixed_point) {
+    defines = [ "OPUS_FIXED_POINT" ]
+  }
+}
+
+config("opus_private_config") {
+  defines = [
+    "OPUS_BUILD",
+    "OPUS_EXPORT=",
+    "ENABLE_HARDENING",
+
+    # Prefer alloca() over variable length arrays which are often inefficient;
+    # the opus code will automatically handle this correctly per-platform.
+    "USE_ALLOCA",
+    "HAVE_ALLOCA_H",
+  ]
+
+  include_dirs = [
+    ".",
+    "celt",
+    "silk",
+  ]
+
+  cflags = []
+
+  defines += [
+    "HAVE_LRINT",
+    "HAVE_LRINTF",
+  ]
+
+  if (is_debug) {
+    # Turn off a warning in opus_decoder.c when compiling without optimization.
+    defines += [ "OPUS_WILL_BE_SLOW" ]
+  }
+
+  if (use_opus_x86_optimization) {
+    defines += [
+      # Run Time CPU Detections (RTCD) is always enabled for x86.
+      "OPUS_HAVE_RTCD",
+      "CPU_INFO_BY_ASM",
+
+      # Chrome always targets SSE2+.
+      "OPUS_X86_MAY_HAVE_SSE",
+      "OPUS_X86_MAY_HAVE_SSE2",
+      "OPUS_X86_PRESUME_SSE",
+      "OPUS_X86_PRESUME_SSE2",
+
+      # Some systems may have SSE4.1+ support.
+      "OPUS_X86_MAY_HAVE_SSE4_1",
+
+      # At present libopus has no AVX functions so no sources are add for this,
+      # if you see linker errors on AVX code the this flag is why.
+      "OPUS_X86_MAY_HAVE_AVX",
+    ]
+  }
+
+  if (use_opus_fixed_point) {
+    defines += [ "FIXED_POINT" ]
+    include_dirs += [ "silk/fixed" ]
+  } else {
+    include_dirs += [ "silk/float" ]
+  }
+}
+
+config("opus_test_config") {
+  include_dirs = [
+    "celt",
+    "silk",
+  ]
+
+  cflags = [ "-Wno-absolute-value" ]
+}
+
+if (use_opus_x86_optimization) {
+  source_set("opus_sse41") {
+    sources = [
+      "celt/x86/pitch_sse4_1.c",
+      "silk/x86/NSQ_del_dec_sse4_1.c",
+      "silk/x86/NSQ_sse4_1.c",
+      "silk/x86/VAD_sse4_1.c",
+      "silk/x86/VQ_WMat_EC_sse4_1.c",
+    ]
+
+    configs += [
+      ":opus_private_config",
+      ":opus_config",
+    ]
+
+    cflags = [ "-msse4.1" ]
+  }
+  # TODO(dalecurtis): If libopus ever adds AVX support, add an opus_avx block.
+}
+
+# Note: Do not add any defines or include_dirs to this target, those should all
+# go in the opus_private_config so they can be shared with intrinsic targets.
+static_library("opus") {
+  sources = [
+    "celt/_kiss_fft_guts.h",
+    "celt/arch.h",
+    "celt/bands.c",
+    "celt/bands.h",
+    "celt/celt.c",
+    "celt/celt.h",
+    "celt/celt_decoder.c",
+    "celt/celt_encoder.c",
+    "celt/celt_lpc.c",
+    "celt/celt_lpc.h",
+    "celt/cpu_support.h",
+    "celt/cwrs.c",
+    "celt/cwrs.h",
+    "celt/ecintrin.h",
+    "celt/entcode.c",
+    "celt/entcode.h",
+    "celt/entdec.c",
+    "celt/entdec.h",
+    "celt/entenc.c",
+    "celt/entenc.h",
+    "celt/fixed_debug.h",
+    "celt/fixed_generic.h",
+    "celt/float_cast.h",
+    "celt/kiss_fft.c",
+    "celt/kiss_fft.h",
+    "celt/laplace.c",
+    "celt/laplace.h",
+    "celt/mathops.c",
+    "celt/mathops.h",
+    "celt/mdct.c",
+    "celt/mdct.h",
+    "celt/mfrngcod.h",
+    "celt/modes.c",
+    "celt/modes.h",
+    "celt/os_support.h",
+    "celt/pitch.c",
+    "celt/pitch.h",
+    "celt/quant_bands.c",
+    "celt/quant_bands.h",
+    "celt/rate.c",
+    "celt/rate.h",
+    "celt/stack_alloc.h",
+    "celt/static_modes_fixed.h",
+    "celt/static_modes_float.h",
+    "celt/vq.c",
+    "celt/vq.h",
+    "include/opus.h",
+    "include/opus_custom.h",
+    "include/opus_defines.h",
+    "include/opus_multistream.h",
+    "include/opus_projection.h",
+    "include/opus_types.h",
+    "silk/A2NLSF.c",
+    "silk/API.h",
+    "silk/CNG.c",
+    "silk/HP_variable_cutoff.c",
+    "silk/Inlines.h",
+    "silk/LPC_analysis_filter.c",
+    "silk/LPC_fit.c",
+    "silk/LPC_inv_pred_gain.c",
+    "silk/LP_variable_cutoff.c",
+    "silk/MacroCount.h",
+    "silk/MacroDebug.h",
+    "silk/NLSF2A.c",
+    "silk/NLSF_VQ.c",
+    "silk/NLSF_VQ_weights_laroia.c",
+    "silk/NLSF_decode.c",
+    "silk/NLSF_del_dec_quant.c",
+    "silk/NLSF_encode.c",
+    "silk/NLSF_stabilize.c",
+    "silk/NLSF_unpack.c",
+    "silk/NSQ.c",
+    "silk/NSQ.h",
+    "silk/NSQ_del_dec.c",
+    "silk/PLC.c",
+    "silk/PLC.h",
+    "silk/SigProc_FIX.h",
+    "silk/VAD.c",
+    "silk/VQ_WMat_EC.c",
+    "silk/ana_filt_bank_1.c",
+    "silk/biquad_alt.c",
+    "silk/bwexpander.c",
+    "silk/bwexpander_32.c",
+    "silk/check_control_input.c",
+    "silk/code_signs.c",
+    "silk/control.h",
+    "silk/control_SNR.c",
+    "silk/control_audio_bandwidth.c",
+    "silk/control_codec.c",
+    "silk/debug.c",
+    "silk/debug.h",
+    "silk/dec_API.c",
+    "silk/decode_core.c",
+    "silk/decode_frame.c",
+    "silk/decode_indices.c",
+    "silk/decode_parameters.c",
+    "silk/decode_pitch.c",
+    "silk/decode_pulses.c",
+    "silk/decoder_set_fs.c",
+    "silk/define.h",
+    "silk/enc_API.c",
+    "silk/encode_indices.c",
+    "silk/encode_pulses.c",
+    "silk/errors.h",
+    "silk/gain_quant.c",
+    "silk/init_decoder.c",
+    "silk/init_encoder.c",
+    "silk/inner_prod_aligned.c",
+    "silk/interpolate.c",
+    "silk/lin2log.c",
+    "silk/log2lin.c",
+    "silk/macros.h",
+    "silk/main.h",
+    "silk/pitch_est_defines.h",
+    "silk/pitch_est_tables.c",
+    "silk/process_NLSFs.c",
+    "silk/quant_LTP_gains.c",
+    "silk/resampler.c",
+    "silk/resampler_down2.c",
+    "silk/resampler_down2_3.c",
+    "silk/resampler_private.h",
+    "silk/resampler_private_AR2.c",
+    "silk/resampler_private_IIR_FIR.c",
+    "silk/resampler_private_down_FIR.c",
+    "silk/resampler_private_up2_HQ.c",
+    "silk/resampler_rom.c",
+    "silk/resampler_rom.h",
+    "silk/resampler_structs.h",
+    "silk/shell_coder.c",
+    "silk/sigm_Q15.c",
+    "silk/sort.c",
+    "silk/stereo_LR_to_MS.c",
+    "silk/stereo_MS_to_LR.c",
+    "silk/stereo_decode_pred.c",
+    "silk/stereo_encode_pred.c",
+    "silk/stereo_find_predictor.c",
+    "silk/stereo_quant_pred.c",
+    "silk/structs.h",
+    "silk/sum_sqr_shift.c",
+    "silk/table_LSF_cos.c",
+    "silk/tables.h",
+    "silk/tables_LTP.c",
+    "silk/tables_NLSF_CB_NB_MB.c",
+    "silk/tables_NLSF_CB_WB.c",
+    "silk/tables_gain.c",
+    "silk/tables_other.c",
+    "silk/tables_pitch_lag.c",
+    "silk/tables_pulses_per_block.c",
+    "silk/tuning_parameters.h",
+    "silk/typedef.h",
+    "src/analysis.c",
+    "src/analysis.h",
+    "src/mapping_matrix.c",
+    "src/mapping_matrix.h",
+    "src/mlp.c",
+    "src/mlp.h",
+    "src/mlp_data.c",
+    "src/opus.c",
+    "src/opus_decoder.c",
+    "src/opus_encoder.c",
+    "src/opus_multistream.c",
+    "src/opus_multistream_decoder.c",
+    "src/opus_multistream_encoder.c",
+    "src/opus_private.h",
+    "src/opus_projection_encoder.c",
+    "src/opus_projection_decoder.c",
+    "src/repacketizer.c",
+    "src/tansig_table.h",
+  ]
+
+  configs += [
+    ":opus_private_config",
+  ]
+  public_configs = [ ":opus_config" ]
+
+  deps = []
+
+  if (use_opus_x86_optimization) {
+    sources += [
+      "celt/x86/celt_lpc_sse.h",
+      "celt/x86/celt_lpc_sse4_1.c",
+      "celt/x86/pitch_sse.c",
+      "celt/x86/pitch_sse.h",
+      "celt/x86/pitch_sse2.c",
+      "celt/x86/vq_sse.h",
+      "celt/x86/vq_sse2.c",
+      "celt/x86/x86_celt_map.c",
+      "celt/x86/x86cpu.c",
+      "celt/x86/x86cpu.h",
+      "silk/x86/SigProc_FIX_sse.h",
+      "silk/x86/main_sse.h",
+      "silk/x86/x86_silk_map.c",
+    ]
+    deps += [ ":opus_sse41" ]
+  }
+
+  if (use_opus_fixed_point) {
+    sources += [
+      "silk/fixed/LTP_analysis_filter_FIX.c",
+      "silk/fixed/LTP_scale_ctrl_FIX.c",
+      "silk/fixed/apply_sine_window_FIX.c",
+      "silk/fixed/autocorr_FIX.c",
+      "silk/fixed/burg_modified_FIX.c",
+      "silk/fixed/corrMatrix_FIX.c",
+      "silk/fixed/encode_frame_FIX.c",
+      "silk/fixed/find_LPC_FIX.c",
+      "silk/fixed/find_LTP_FIX.c",
+      "silk/fixed/find_pitch_lags_FIX.c",
+      "silk/fixed/find_pred_coefs_FIX.c",
+      "silk/fixed/k2a_FIX.c",
+      "silk/fixed/k2a_Q16_FIX.c",
+      "silk/fixed/main_FIX.h",
+      "silk/fixed/noise_shape_analysis_FIX.c",
+      "silk/fixed/pitch_analysis_core_FIX.c",
+      "silk/fixed/process_gains_FIX.c",
+      "silk/fixed/regularize_correlations_FIX.c",
+      "silk/fixed/residual_energy16_FIX.c",
+      "silk/fixed/residual_energy_FIX.c",
+      "silk/fixed/schur64_FIX.c",
+      "silk/fixed/schur_FIX.c",
+      "silk/fixed/structs_FIX.h",
+      "silk/fixed/vector_ops_FIX.c",
+      "silk/fixed/warped_autocorrelation_FIX.c",
+    ]
+  } else {
+    sources += [
+      "silk/float/LPC_analysis_filter_FLP.c",
+      "silk/float/LPC_inv_pred_gain_FLP.c",
+      "silk/float/LTP_analysis_filter_FLP.c",
+      "silk/float/LTP_scale_ctrl_FLP.c",
+      "silk/float/SigProc_FLP.h",
+      "silk/float/apply_sine_window_FLP.c",
+      "silk/float/autocorrelation_FLP.c",
+      "silk/float/burg_modified_FLP.c",
+      "silk/float/bwexpander_FLP.c",
+      "silk/float/corrMatrix_FLP.c",
+      "silk/float/encode_frame_FLP.c",
+      "silk/float/energy_FLP.c",
+      "silk/float/find_LPC_FLP.c",
+      "silk/float/find_LTP_FLP.c",
+      "silk/float/find_pitch_lags_FLP.c",
+      "silk/float/find_pred_coefs_FLP.c",
+      "silk/float/inner_product_FLP.c",
+      "silk/float/k2a_FLP.c",
+      "silk/float/main_FLP.h",
+      "silk/float/noise_shape_analysis_FLP.c",
+      "silk/float/pitch_analysis_core_FLP.c",
+      "silk/float/process_gains_FLP.c",
+      "silk/float/regularize_correlations_FLP.c",
+      "silk/float/residual_energy_FLP.c",
+      "silk/float/scale_copy_vector_FLP.c",
+      "silk/float/scale_vector_FLP.c",
+      "silk/float/schur_FLP.c",
+      "silk/float/sort_FLP.c",
+      "silk/float/structs_FLP.h",
+      "silk/float/warped_autocorrelation_FLP.c",
+      "silk/float/wrappers_FLP.c",
+    ]
+  }
+}
+