diff --git a/.gitmodules b/.gitmodules
index 3f522ce0..cab30a90 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -28,6 +28,9 @@
 [submodule "sysaudio/upstream"]
 	path = sysaudio/upstream
 	url = https://github.com/hexops/soundio
+[submodule "basisu/upstream"]
+	path = basisu/upstream
+	url = https://github.com/hexops/basisu
 [submodule "examples/image-blur/assets"]
 	path = examples/image-blur/assets
 	url = https://github.com/hexops/mach-example-assets
diff --git a/basisu/.gitmodules b/basisu/.gitmodules
new file mode 100644
index 00000000..abc59fa0
--- /dev/null
+++ b/basisu/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "upstream"]
+	path = upstream
+	url = https://github.com/hexops/basisu
\ No newline at end of file
diff --git a/basisu/build.zig b/basisu/build.zig
new file mode 100644
index 00000000..3d656c86
--- /dev/null
+++ b/basisu/build.zig
@@ -0,0 +1,124 @@
+const std = @import("std");
+const Builder = std.build.Builder;
+
+const basisu_root = thisDir() ++ "/upstream/basisu";
+
+pub const pkg = std.build.Pkg{
+    .name = "basisu",
+    .source = .{
+        .path = "src/main.zig",
+    },
+};
+
+pub fn build(b: *Builder) void {
+    const mode = b.standardReleaseOptions();
+    const target = b.standardTargetOptions(.{});
+
+    const test_step = b.step("test", "Run library tests");
+    test_step.dependOn(&testStep(b, mode, target).step);
+}
+
+pub fn testStep(b: *Builder, mode: std.builtin.Mode, target: std.zig.CrossTarget) *std.build.RunStep {
+    const main_tests = b.addTestExe("basisu-tests", comptime thisDir() ++ "/src/main.zig");
+    main_tests.setBuildMode(mode);
+    main_tests.setTarget(target);
+    main_tests.main_pkg_path = thisDir();
+    link(b, main_tests, .{
+        .encoder = true,
+        .transcoder = true,
+    });
+    main_tests.install();
+    return main_tests.run();
+}
+
+pub fn link(b: *Builder, step: *std.build.LibExeObjStep, options: Options) void {
+    if (options.encoder) {
+        step.linkLibrary(buildEncoder(b));
+        step.addCSourceFile(comptime thisDir() ++ "/src/encoder/wrapper.cpp", &.{});
+        step.addIncludeDir(basisu_root ++ "/encoder");
+    }
+    if (options.transcoder) {
+        step.linkLibrary(buildTranscoder(b));
+        step.addCSourceFile(comptime thisDir() ++ "/src/transcoder/wrapper.cpp", &.{});
+        step.addIncludeDir(basisu_root ++ "/transcoder");
+    }
+}
+
+pub fn buildEncoder(b: *Builder) *std.build.LibExeObjStep {
+    // TODO(build-system): https://github.com/hexops/mach/issues/229#issuecomment-1100958939
+    ensureDependencySubmodule(b.allocator, "upstream") catch unreachable;
+
+    const encoder = b.addStaticLibrary("basisu-encoder", null);
+    encoder.linkLibCpp();
+    encoder.addCSourceFiles(
+        encoder_sources,
+        &.{},
+    );
+
+    encoder.defineCMacro("BASISU_FORCE_DEVEL_MESSAGES", "0");
+    encoder.defineCMacro("BASISD_SUPPORT_KTX2_ZSTD", "0");
+    encoder.install();
+    return encoder;
+}
+
+pub fn buildTranscoder(b: *Builder) *std.build.LibExeObjStep {
+    // TODO(build-system): https://github.com/hexops/mach/issues/229#issuecomment-1100958939
+    ensureDependencySubmodule(b.allocator, "upstream") catch unreachable;
+
+    const transcoder = b.addStaticLibrary("basisu-transcoder", null);
+    transcoder.linkLibCpp();
+    transcoder.addCSourceFiles(
+        transcoder_sources,
+        &.{},
+    );
+
+    transcoder.defineCMacro("BASISU_FORCE_DEVEL_MESSAGES", "0");
+    transcoder.defineCMacro("BASISD_SUPPORT_KTX2_ZSTD", "0");
+    transcoder.install();
+    return transcoder;
+}
+
+pub const Options = struct {
+    encoder: bool,
+    transcoder: bool,
+};
+
+fn thisDir() []const u8 {
+    return std.fs.path.dirname(@src().file) orelse ".";
+}
+
+fn ensureDependencySubmodule(allocator: std.mem.Allocator, path: []const u8) !void {
+    if (std.process.getEnvVarOwned(allocator, "NO_ENSURE_SUBMODULES")) |no_ensure_submodules| {
+        if (std.mem.eql(u8, no_ensure_submodules, "true")) return;
+    } else |_| {}
+    var child = std.ChildProcess.init(&.{ "git", "submodule", "update", "--init", path }, allocator);
+    child.cwd = (comptime thisDir());
+    child.stderr = std.io.getStdErr();
+    child.stdout = std.io.getStdOut();
+
+    _ = try child.spawnAndWait();
+}
+
+const transcoder_sources = &[_][]const u8{
+    basisu_root ++ "/transcoder/basisu_transcoder.cpp",
+};
+
+const encoder_sources = &[_][]const u8{
+    basisu_root ++ "/encoder/basisu_backend.cpp",
+    basisu_root ++ "/encoder/basisu_basis_file.cpp",
+    basisu_root ++ "/encoder/basisu_bc7enc.cpp",
+    basisu_root ++ "/encoder/basisu_comp.cpp",
+    basisu_root ++ "/encoder/basisu_enc.cpp",
+    basisu_root ++ "/encoder/basisu_etc.cpp",
+    basisu_root ++ "/encoder/basisu_frontend.cpp",
+    basisu_root ++ "/encoder/basisu_gpu_texture.cpp",
+    basisu_root ++ "/encoder/basisu_kernels_sse.cpp",
+    basisu_root ++ "/encoder/basisu_opencl.cpp",
+    basisu_root ++ "/encoder/basisu_pvrtc1_4.cpp",
+    basisu_root ++ "/encoder/basisu_resample_filters.cpp",
+    basisu_root ++ "/encoder/basisu_resampler.cpp",
+    basisu_root ++ "/encoder/basisu_ssim.cpp",
+    basisu_root ++ "/encoder/basisu_uastc_enc.cpp",
+    basisu_root ++ "/encoder/jpgd.cpp",
+    basisu_root ++ "/encoder/pvpngreader.cpp",
+};
diff --git a/basisu/src/encoder.zig b/basisu/src/encoder.zig
new file mode 100644
index 00000000..825f467d
--- /dev/null
+++ b/basisu/src/encoder.zig
@@ -0,0 +1,259 @@
+const std = @import("std");
+const b = @import("encoder/binding.zig");
+const BasisTextureFormat = @import("main.zig").BasisTextureFormat;
+const testing = std.testing;
+
+/// Must be called before encoding anything
+pub fn init_encoder() void {
+    b.basisu_encoder_init();
+}
+
+pub const Compressor = struct {
+    pub const Error = error{
+        InitializationFailed,
+        ValidationFailed,
+        EncodingUASTCFailed,
+        CannotReadSourceImages,
+        FrontendFault,
+        FrontendExtractionFailed,
+        BackendFault,
+        CannotCreateBasisFile,
+        CannotWriteOutput,
+        UASTCRDOPostProcessFailed,
+        CannotCreateKTX2File,
+    };
+
+    handle: *b.Compressor,
+
+    pub fn init(params: CompressorParams) error{Unknown}!Compressor {
+        return Compressor{
+            .handle = if (b.compressor_init(params.handle)) |v| v else return error.Unknown,
+        };
+    }
+
+    pub fn deinit(self: Compressor) void {
+        b.compressor_deinit(self.handle);
+    }
+
+    pub fn process(self: Compressor) Error!void {
+        return switch (b.compressor_process(self.handle)) {
+            0 => {},
+            1 => error.InitializationFailed,
+            2 => error.CannotReadSourceImages,
+            3 => error.ValidationFailed,
+            4 => error.EncodingUASTCFailed,
+            5 => error.FrontendFault,
+            6 => error.FrontendExtractionFailed,
+            7 => error.BackendFault,
+            8 => error.CannotCreateBasisFile,
+            9 => error.UASTCRDOPostProcessFailed,
+            10 => error.CannotCreateKTX2File,
+            else => unreachable,
+        };
+    }
+
+    /// output will be freed with `Compressor.deinit`
+    pub fn output(self: Compressor) []const u8 {
+        return b.compressor_get_output(self.handle)[0..b.compressor_get_output_size(self.handle)];
+    }
+
+    pub fn outputBitsPerTexel(self: Compressor) f64 {
+        return b.compressor_get_output_bits_per_texel(self.handle);
+    }
+
+    pub fn anyImageHasAlpha(self: Compressor) bool {
+        return b.compressor_get_any_source_image_has_alpha(self.handle);
+    }
+};
+
+pub const CompressorParams = struct {
+    handle: *b.CompressorParams,
+
+    pub fn init(threads_count: u32) CompressorParams {
+        const h = CompressorParams{ .handle = b.compressor_params_init() };
+        h.setStatusOutput(false);
+        b.compressor_params_set_thread_count(h.handle, threads_count);
+        return h;
+    }
+
+    pub fn deinit(self: CompressorParams) void {
+        b.compressor_params_deinit(self.handle);
+    }
+
+    pub fn clear(self: CompressorParams) void {
+        b.compressor_params_clear(self.handle);
+    }
+
+    pub fn setStatusOutput(self: CompressorParams, enable_output: bool) void {
+        b.compressor_params_set_status_output(self.handle, enable_output);
+    }
+
+    /// `level` ranges from [1, 255]
+    pub fn setQualityLevel(self: CompressorParams, level: u8) void {
+        b.compressor_params_set_quality_level(self.handle, level);
+    }
+
+    pub fn getPackUASTCFlags(self: CompressorParams) PackUASTCFlags {
+        return PackUASTCFlags.from(b.compressor_params_get_pack_uastc_flags(self.handle));
+    }
+
+    pub fn setPackUASTCFlags(self: CompressorParams, flags: PackUASTCFlags) void {
+        b.compressor_params_set_pack_uastc_flags(self.handle, flags.cast());
+    }
+
+    pub fn setBasisFormat(self: CompressorParams, format: BasisTextureFormat) void {
+        b.compressor_params_set_uastc(self.handle, switch (format) {
+            .etc1s => false,
+            .uastc4x4 => true,
+        });
+    }
+
+    pub fn setColorSpace(self: CompressorParams, color_space: ColorSpace) void {
+        b.compressor_params_set_perceptual(self.handle, switch (color_space) {
+            .linear => false,
+            .srgb => true,
+        });
+    }
+
+    pub fn setMipColorSpace(self: CompressorParams, color_space: ColorSpace) void {
+        b.compressor_params_set_mip_srgb(self.handle, switch (color_space) {
+            .linear => false,
+            .srgb => true,
+        });
+    }
+
+    /// Disable selector RDO, for faster compression but larger files.
+    /// Enabled by default
+    pub fn setSelectorRDO(self: CompressorParams, enable: bool) void {
+        b.compressor_params_set_no_selector_rdo(self.handle, !enable);
+    }
+
+    /// Enabled by default
+    pub fn setEndpointRDO(self: CompressorParams, enable: bool) void {
+        b.compressor_params_set_no_endpoint_rdo(self.handle, !enable);
+    }
+
+    pub fn setRDO_UASTC(self: CompressorParams, enable: bool) void {
+        b.compressor_params_set_rdo_uastc(self.handle, enable);
+    }
+
+    pub fn setRDO_UASTCQualityScalar(self: CompressorParams, quality: f32) void {
+        b.compressor_params_set_rdo_uastc_quality_scalar(self.handle, quality);
+    }
+
+    pub fn setGenerateMipMaps(self: CompressorParams, enable: bool) void {
+        b.compressor_params_set_generate_mipmaps(self.handle, enable);
+    }
+
+    pub fn setMipSmallestDimension(self: CompressorParams, smallest_dimension: i32) void {
+        b.compressor_params_set_mip_smallest_dimension(self.handle, smallest_dimension);
+    }
+
+    /// Resizes sources list and creates a new Image in case index is out of bounds
+    pub fn getImageSource(self: CompressorParams, index: u32) Image {
+        return .{ .handle = b.compressor_params_get_or_create_source_image(self.handle, index) };
+    }
+
+    pub fn resizeImageSource(self: CompressorParams, new_size: u32) void {
+        b.compressor_params_resize_source_image_list(self.handle, new_size);
+    }
+
+    pub fn clearImageSource(self: CompressorParams) void {
+        b.compressor_params_clear_source_image_list(self.handle);
+    }
+};
+
+pub const Image = struct {
+    handle: *b.Image,
+
+    pub fn fill(self: Image, data: []const u8, w: u32, h: u32, channels: u3) void {
+        b.compressor_image_fill(self.handle, data.ptr, w, h, channels);
+    }
+
+    pub fn resize(self: Image, w: u32, h: u32, p: ?u32) void {
+        b.compressor_image_resize(self.handle, w, h, p orelse std.math.maxInt(u32));
+    }
+
+    pub fn width(self: Image) u32 {
+        return b.compressor_image_get_width(self.handle);
+    }
+
+    pub fn height(self: Image) u32 {
+        return b.compressor_image_get_height(self.handle);
+    }
+
+    pub fn pitch(self: Image) u32 {
+        return b.compressor_image_get_pitch(self.handle);
+    }
+
+    pub fn totalPixels(self: Image) u32 {
+        return b.compressor_image_get_total_pixels(self.handle);
+    }
+
+    pub fn blockWidth(self: Image, w: u32) u32 {
+        return (self.width() + (w - 1)) / w;
+    }
+
+    pub fn blockHeight(self: Image, h: u32) u32 {
+        return (self.height() + (h - 1)) / h;
+    }
+
+    pub fn totalBlocks(self: Image, w: u32, h: u32) u32 {
+        return self.blockWidth(w) * self.blockHeight(h);
+    }
+};
+
+pub const PackUASTCFlags = packed struct {
+    fastest: bool = false,
+    faster: bool = false,
+    default: bool = false,
+    slower: bool = false,
+    verySlow: bool = false,
+    mask: bool = false,
+    favor_uastc_error: bool = false,
+    favor_bc7_error: bool = false,
+    etc1_faster_hints: bool = false,
+    etc1_fastest_hints: bool = false,
+    etc1_disable_flip_and_individual: bool = false,
+    favor_simpler_modes: bool = false,
+
+    pub const Flag = enum(u32) {
+        fastest = 0,
+        faster = 1,
+        default = 2,
+        slower = 3,
+        verySlow = 4,
+        mask = 0xF,
+        favor_uastc_error = 8,
+        favor_bc7_error = 16,
+        etc1_faster_hints = 64,
+        etc1_fastest_hints = 128,
+        etc1_disable_flip_and_individual = 256,
+        favor_simpler_modes = 512,
+    };
+
+    pub fn from(bits: u32) PackUASTCFlags {
+        var value = PackUASTCFlags{};
+        inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
+            if (bits & (@enumToInt(@field(Flag, field_name))) != 0) {
+                @field(value, field_name) = true;
+            }
+        }
+        return value;
+    }
+
+    pub fn cast(self: PackUASTCFlags) u32 {
+        var value: u32 = 0;
+        inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
+            if (@field(self, field_name)) {
+                value |= @enumToInt(@field(Flag, field_name));
+            }
+        }
+        return value;
+    }
+};
+
+pub const ColorSpace = enum {
+    linear,
+    srgb,
+};
diff --git a/basisu/src/encoder/binding.zig b/basisu/src/encoder/binding.zig
new file mode 100644
index 00000000..aa9e86e6
--- /dev/null
+++ b/basisu/src/encoder/binding.zig
@@ -0,0 +1,42 @@
+pub const Compressor = opaque {};
+pub const CompressorParams = opaque {};
+pub const Image = opaque {};
+
+pub extern fn basisu_encoder_init() void;
+
+pub extern fn compressor_params_init() *CompressorParams;
+pub extern fn compressor_params_deinit(*CompressorParams) void;
+pub extern fn compressor_params_clear(*CompressorParams) void;
+pub extern fn compressor_params_set_status_output(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_thread_count(*CompressorParams, u32) void;
+pub extern fn compressor_params_set_quality_level(*CompressorParams, c_int) void;
+pub extern fn compressor_params_get_pack_uastc_flags(*CompressorParams) u32;
+pub extern fn compressor_params_set_pack_uastc_flags(*CompressorParams, u32) void;
+pub extern fn compressor_params_set_uastc(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_perceptual(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_mip_srgb(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_no_selector_rdo(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_no_endpoint_rdo(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_rdo_uastc(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_rdo_uastc_quality_scalar(*CompressorParams, f32) void;
+pub extern fn compressor_params_set_generate_mipmaps(*CompressorParams, bool) void;
+pub extern fn compressor_params_set_mip_smallest_dimension(*CompressorParams, c_int) void;
+pub extern fn compressor_params_get_or_create_source_image(*CompressorParams, u32) *Image;
+pub extern fn compressor_params_resize_source_image_list(*CompressorParams, usize) void;
+pub extern fn compressor_params_clear_source_image_list(*CompressorParams) void;
+
+pub extern fn compressor_image_fill(*Image, [*]const u8, u32, u32, u32) void;
+pub extern fn compressor_image_resize(*Image, u32, u32, u32) void;
+pub extern fn compressor_image_get_width(*Image) u32;
+pub extern fn compressor_image_get_height(*Image) u32;
+pub extern fn compressor_image_get_pitch(*Image) u32;
+pub extern fn compressor_image_get_total_pixels(*Image) u32;
+
+pub extern fn compressor_init(*CompressorParams) ?*Compressor;
+pub extern fn compressor_deinit(*Compressor) void;
+pub extern fn compressor_process(*Compressor) u32;
+
+pub extern fn compressor_get_output(*Compressor) [*]const u8;
+pub extern fn compressor_get_output_size(*Compressor) u32;
+pub extern fn compressor_get_output_bits_per_texel(*Compressor) f64;
+pub extern fn compressor_get_any_source_image_has_alpha(*Compressor) bool;
diff --git a/basisu/src/encoder/wrapper.cpp b/basisu/src/encoder/wrapper.cpp
new file mode 100644
index 00000000..d3d48f82
--- /dev/null
+++ b/basisu/src/encoder/wrapper.cpp
@@ -0,0 +1,176 @@
+#include <basisu_comp.h>
+#include <basisu_enc.h>
+#include <cstdbool>
+#include <cstdint>
+
+extern "C" {
+void basisu_encoder_init() { basisu::basisu_encoder_init(); }
+
+basisu::basis_compressor_params *compressor_params_init() {
+  return new basisu::basis_compressor_params();
+};
+
+void compressor_params_deinit(basisu::basis_compressor_params *params) {
+  delete params;
+}
+
+void compressor_params_clear(basisu::basis_compressor_params *params) {
+  params->clear();
+}
+
+void compressor_params_set_status_output(
+    basisu::basis_compressor_params *params, bool status_output) {
+  params->m_status_output = status_output;
+}
+
+void compressor_params_set_thread_count(basisu::basis_compressor_params *params,
+                                        uint32_t thread_count) {
+  params->m_pJob_pool = new basisu::job_pool(thread_count);
+}
+
+void compressor_params_set_quality_level(
+    basisu::basis_compressor_params *params, uint8_t quality_level) {
+  params->m_quality_level = quality_level;
+}
+
+uint32_t compressor_params_get_pack_uastc_flags(
+    basisu::basis_compressor_params *params) {
+  return params->m_pack_uastc_flags;
+}
+
+void compressor_params_set_pack_uastc_flags(
+    basisu::basis_compressor_params *params, uint32_t pack_uastc_flags) {
+  params->m_pack_uastc_flags = pack_uastc_flags;
+}
+
+void compressor_params_set_uastc(basisu::basis_compressor_params *params,
+                                 bool is_uastc) {
+  params->m_uastc = is_uastc;
+}
+
+void compressor_params_set_perceptual(basisu::basis_compressor_params *params,
+                                      bool perceptual) {
+  params->m_perceptual = perceptual;
+}
+
+void compressor_params_set_mip_srgb(basisu::basis_compressor_params *params,
+                                    bool mip_srgb) {
+  params->m_mip_srgb = mip_srgb;
+}
+
+void compressor_params_set_no_selector_rdo(
+    basisu::basis_compressor_params *params, bool no_selector_rdo) {
+  params->m_no_selector_rdo = no_selector_rdo;
+}
+
+void compressor_params_set_no_endpoint_rdo(
+    basisu::basis_compressor_params *params, bool no_endpoint_rdo) {
+  params->m_no_endpoint_rdo = no_endpoint_rdo;
+}
+
+void compressor_params_set_rdo_uastc(basisu::basis_compressor_params *params,
+                                     bool rdo_uastc) {
+  params->m_rdo_uastc = rdo_uastc;
+}
+
+void compressor_params_set_generate_mipmaps(
+    basisu::basis_compressor_params *params, bool generate_mipmaps) {
+  params->m_mip_gen = generate_mipmaps;
+}
+
+void compressor_params_set_rdo_uastc_quality_scalar(
+    basisu::basis_compressor_params *params, float rdo_uastc_quality_scalar) {
+  params->m_rdo_uastc_quality_scalar = rdo_uastc_quality_scalar;
+}
+
+void compressor_params_set_mip_smallest_dimension(
+    basisu::basis_compressor_params *params, int mip_smallest_dimension) {
+  params->m_mip_smallest_dimension = mip_smallest_dimension;
+}
+
+basisu::image *compressor_params_get_or_create_source_image(
+    basisu::basis_compressor_params *params, uint32_t index) {
+  if (params->m_source_images.size() < index + 1) {
+    params->m_source_images.resize(index + 1);
+  }
+
+  return &params->m_source_images[index];
+}
+
+void compressor_params_resize_source_image_list(
+    basisu::basis_compressor_params *params, size_t size) {
+  params->m_source_images.resize(size);
+}
+
+void compressor_params_clear_source_image_list(
+    basisu::basis_compressor_params *params) {
+  params->clear();
+}
+
+///
+
+void compressor_image_fill(basisu::image *image, const uint8_t *pData,
+                           uint32_t width, uint32_t height, uint32_t comps) {
+  image->init(pData, width, height, comps);
+}
+
+void compressor_image_resize(basisu::image *image, uint32_t w, uint32_t h,
+                             uint32_t p) {
+  image->resize(w, h, p);
+}
+
+uint32_t compressor_image_get_width(basisu::image *image) {
+  return image->get_width();
+}
+
+uint32_t compressor_image_get_height(basisu::image *image) {
+  return image->get_height();
+}
+
+uint32_t compressor_image_get_pitch(basisu::image *image) {
+  return image->get_pitch();
+}
+
+uint32_t compressor_image_get_total_pixels(basisu::image *image) {
+  return image->get_total_pixels();
+}
+
+///
+
+basisu::basis_compressor *
+compressor_init(basisu::basis_compressor_params *params) {
+  auto comp = new basisu::basis_compressor();
+  if (comp->init(*params))
+    return comp;
+  else
+    return nullptr;
+}
+
+void compressor_deinit(basisu::basis_compressor *compressor) {
+  delete compressor;
+}
+
+basisu::basis_compressor::error_code
+compressor_process(basisu::basis_compressor *compressor) {
+  return compressor->process();
+}
+
+const uint8_t *compressor_get_output(basisu::basis_compressor *compressor) {
+  return compressor->get_output_basis_file().data();
+}
+
+uint32_t
+compressor_get_output_size(const basisu::basis_compressor *compressor) {
+  return compressor->get_basis_file_size();
+}
+
+double compressor_get_output_bits_per_texel(
+    const basisu::basis_compressor *compressor) {
+  return compressor->get_basis_bits_per_texel();
+}
+
+bool compressor_get_any_source_image_has_alpha(
+    const basisu::basis_compressor *compressor) {
+  return compressor->get_any_source_image_has_alpha();
+}
+}
\ No newline at end of file
diff --git a/basisu/src/main.zig b/basisu/src/main.zig
new file mode 100644
index 00000000..5a57de91
--- /dev/null
+++ b/basisu/src/main.zig
@@ -0,0 +1,45 @@
+pub usingnamespace @import("encoder.zig");
+pub usingnamespace @import("transcoder.zig");
+
+pub const BasisTextureFormat = enum(u1) {
+    etc1s = 0,
+    uastc4x4 = 1,
+};
+
+// Test
+
+const t = @import("transcoder.zig");
+const e = @import("encoder.zig");
+const testing = @import("std").testing;
+
+test "reference decls" {
+    testing.refAllDeclsRecursive(t);
+    testing.refAllDeclsRecursive(e);
+}
+
+test "encode/transcode" {
+    // Encode
+    e.init_encoder();
+
+    const params = e.CompressorParams.init(1);
+    params.setGenerateMipMaps(true);
+    params.setBasisFormat(.uastc4x4);
+    params.setPackUASTCFlags(.{ .fastest = true });
+    defer params.deinit();
+
+    const image = params.getImageSource(0);
+    image.fill(@embedFile("../test/ziggy.png"), 379, 316, 4);
+
+    const comp = try e.Compressor.init(params);
+    try comp.process();
+
+    // Transcode
+    t.init_transcoder();
+
+    const trans = try t.Transcoder.init(comp.output());
+    defer trans.deinit();
+
+    var out_buf = try testing.allocator.alloc(u8, try trans.calcTranscodedSize(0, 0, .astc_4x4_rgba));
+    defer testing.allocator.free(out_buf);
+    try trans.transcode(out_buf, 0, 0, .astc_4x4_rgba, .{});
+}
diff --git a/basisu/src/transcoder.zig b/basisu/src/transcoder.zig
new file mode 100644
index 00000000..aaa2f55d
--- /dev/null
+++ b/basisu/src/transcoder.zig
@@ -0,0 +1,229 @@
+const std = @import("std");
+const b = @import("transcoder/binding.zig");
+const BasisTextureFormat = @import("main.zig").BasisTextureFormat;
+const testing = std.testing;
+
+/// Must be called before a `.basis` file can be transcoded.
+/// NOTE: this function *isn't* thread safe.
+pub fn init_transcoder() void {
+    b.basisu_transcoder_init();
+}
+
+/// Returns true if the specified format was enabled at compile time.
+pub fn isFormatEnabled(self: BasisTextureFormat, transcoder_format: Transcoder.TextureFormat) bool {
+    return b.transcoder_is_format_supported(@enumToInt(self), @enumToInt(transcoder_format));
+}
+
+pub const Transcoder = struct {
+    handle: *b.BasisFile,
+
+    pub fn init(src: []const u8) error{Unknown}!Transcoder {
+        const h = b.transcoder_init(src.ptr, @intCast(u32, src.len));
+        return if (!b.transcoder_start_transcoding(h))
+            error.Unknown
+        else .{ .handle = h };
+    }
+
+    pub fn deinit(self: Transcoder) void {
+        if (!b.transcoder_stop_transcoding(self.handle))
+            unreachable;
+        b.transcoder_deinit(self.handle);
+    }
+
+    /// Returns the total number of images in the basis file (always 1 or more).
+    /// Note that the number of mipmap levels for each image may differ, and that images may have different resolutions.
+    pub fn getImageCount(self: Transcoder) u32 {
+        return b.transcoder_get_images_count(self.handle);
+    }
+
+    /// Returns the number of mipmap levels in an image.
+    pub fn getImageLevelCount(self: Transcoder, image_index: u32) u32 {
+        return b.transcoder_get_levels_count(self.handle, image_index);
+    }
+
+    /// Returns basic information about an image.
+    /// Note that orig_width/orig_height may not be a multiple of 4.
+    pub fn getImageLevelDescriptor(self: Transcoder, image_index: u32, level_index: u32) error{OutOfBoundsLevelIndex}!ImageLevelDescriptor {
+        var desc: ImageLevelDescriptor = undefined;
+        return if (b.transcoder_get_image_level_desc(
+            self.handle,
+            image_index,
+            level_index,
+            &desc.original_width,
+            &desc.original_height,
+            &desc.block_count,
+        ))
+            desc
+        else
+            error.OutOfBoundsLevelIndex;
+    }
+
+    /// Returns the bytes neeeded to store output.
+    pub fn calcTranscodedSize(self: Transcoder, image_index: u32, level_index: u32, format: TextureFormat) error{OutOfBoundsLevelIndex}!u32 {
+        var size: u32 = undefined;
+        return if (b.transcoder_get_image_transcoded_size(self.handle, image_index, level_index, @enumToInt(format), &size))
+            size
+        else
+            error.OutOfBoundsLevelIndex;
+    }
+
+    pub const TranscodeParams = struct {
+        decode_flags: ?DecodeFlags = null,
+        /// Output row pitch in blocks or pixels.
+        /// Should be at least the image level's total_blocks (num_blocks_x * num_blocks_y),
+        /// or the total number of output pixels if fmt==cTFRGBA32.
+        output_row_pitch: ?u32 = null,
+        /// Output rows in pixels
+        /// Ignored unless fmt is uncompressed (cRGBA32, etc.).
+        /// The total number of output rows in the output buffer. If 0,
+        /// the transcoder assumes the slice's orig_height (NOT num_blocks_y * 4).
+        output_rows: ?u32 = null,
+    };
+
+    /// Decodes a single mipmap level from the .basis file to any of the supported output texture formats.
+    /// Currently, to decode to PVRTC1 the basis texture's dimensions in pixels must be a power of 2,
+    /// due to PVRTC1 format requirements.
+    /// NOTE:
+    /// - `transcoder_init()` must have been called first to initialize
+    ///   the transcoder lookup tables before calling this function.
+    /// - This method assumes the output texture buffer is readable.
+    ///   In some cases to handle alpha, the transcoder will write temporary data
+    ///   to the output texture in a first pass, which will be read in a second pass.
+    pub fn transcode(
+        self: Transcoder,
+        out_buf: []u8,
+        image_index: u32,
+        level_index: u32,
+        format: TextureFormat,
+        params: TranscodeParams,
+    ) error{Unknown}!void {
+        if (!b.transcoder_transcode(
+            self.handle,
+            out_buf.ptr,
+            @intCast(u32, out_buf.len),
+            image_index,
+            level_index,
+            @enumToInt(format),
+            if (params.decode_flags) |f| f.cast() else 0,
+            params.output_row_pitch orelse 0,
+            params.output_rows orelse 0,
+        )) return error.Unknown;
+    }
+
+    pub const ImageLevelDescriptor = struct {
+        original_width: u32,
+        original_height: u32,
+        block_count: u32,
+    };
+
+    pub const DecodeFlags = packed struct {
+        pvrtc_decode_to_next_pow_2: bool = false,
+        transcode_alpha_data_to_opaque_formats: bool = false,
+        bc1_forbid_three_color_blocks: bool = false,
+        output_has_alpha_indices: bool = false,
+        high_quality: bool = false,
+
+        pub const Flag = enum(u32) {
+            pvrtc_decode_to_next_pow_2 = 2,
+            transcode_alpha_data_to_opaque_formats = 4,
+            bc1_forbid_three_color_blocks = 8,
+            output_has_alpha_indices = 16,
+            high_quality = 32,
+        };
+
+        pub fn from(bits: u32) DecodeFlags {
+            var value = DecodeFlags{};
+            inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
+                if (bits & (@enumToInt(@field(Flag, field_name))) != 0) {
+                    @field(value, field_name) = true;
+                }
+            }
+            return value;
+        }
+
+        pub fn cast(self: DecodeFlags) u32 {
+            var value: u32 = 0;
+            inline for (comptime std.meta.fieldNames(Flag)) |field_name| {
+                if (@field(self, field_name)) {
+                    value |= @enumToInt(@field(Flag, field_name));
+                }
+            }
+            return value;
+        }
+    };
+
+    pub const TextureFormat = enum(u5) {
+        etc1_rgb = 0,
+        etc2_rgba = 1,
+        bc1_rgb = 2,
+        bc3_rgba = 3,
+        bc4_r = 4,
+        bc5_rg = 5,
+        bc7_rgba = 6,
+        bc7_alt = 7,
+        pvrtc1_4_rgb = 8,
+        pvrtc1_4_rgba = 9,
+        astc_4x4_rgba = 10,
+        atc_rgb = 11,
+        atc_rgba = 12,
+        rgba32 = 13,
+        rgb565 = 14,
+        bgr565 = 15,
+        rgba4444 = 16,
+        fxt1_rgb = 17,
+        pvrtc2_4_rgb = 18,
+        pvrtc2_4_rgba = 19,
+        etc2_eac_r11 = 20,
+        etc2_eac_rg11 = 21,
+
+        pub fn isEnabled(
+            self: TextureFormat,
+            basis_texture_format: BasisTextureFormat,
+        ) bool {
+            return isFormatEnabled(basis_texture_format, self);
+        }
+
+        pub fn bytesPerBlockOrPixel(self: TextureFormat) u5 {
+            return switch (self) {
+                .rgb565, .bgr565, .rgba4444 => return 2,
+                .rgba32 => return 4,
+                .etc1_rgb, .bc1_rgb, .bc4_r, .pvrtc1_4_rgb, .pvrtc1_4_rgba, .atc_rgb, .pvrtc2_4_rgb, .pvrtc2_4_rgba, .etc2_eac_r11 => 8,
+                .bc7_rgba, .bc7_alt, .etc2_rgba, .bc3_rgba, .bc5_rg, .astc_4x4_rgba, .atc_rgba, .fxt1_rgb, .etc2_eac_rg11 => return 16,
+            };
+        }
+    };
+
+    pub const BlockFormat = enum(u5) {
+        etc1 = 0,
+        etc2_rgba = 1,
+        bc1 = 2,
+        bc3 = 3,
+        bc4 = 4,
+        bc5 = 5,
+        pvrtc1_4_rgb = 6,
+        pvrtc1_4_rgba = 7,
+        bc7 = 8,
+        bc7_m5_color = 9,
+        bc7_m5_alpha = 10,
+        etc2_eac_a8 = 11,
+        astc_4x4 = 12,
+        atc_rgb = 13,
+        atc_rgba_interpolated_alpha = 14,
+        fxt1_rgb = 15,
+        pvrtc2_4_rgb = 16,
+        pvrtc2_4_rgba = 17,
+        etc2_eac_r11 = 18,
+        etc2_eac_rg11 = 19,
+        indices = 20,
+        rgb32 = 21,
+        rgba32 = 23,
+        a32 = 24,
+        rgb565 = 25,
+        bgr565 = 26,
+        rgba4444_color = 27,
+        rgba4444_alpha = 28,
+        rgba4444_color_opaque = 29,
+        rgba4444 = 30,
+        uastc_4x4 = 31,
+    };
+};
diff --git a/basisu/src/transcoder/binding.zig b/basisu/src/transcoder/binding.zig
new file mode 100644
index 00000000..b012e737
--- /dev/null
+++ b/basisu/src/transcoder/binding.zig
@@ -0,0 +1,38 @@
+pub const BasisFile = opaque {};
+
+pub extern fn basisu_transcoder_init() void;
+
+pub extern fn transcoder_is_format_supported(tex_type: u32, fmt: u32) bool;
+
+pub extern fn transcoder_init([*]const u8, u32) *BasisFile;
+pub extern fn transcoder_deinit(*BasisFile) void;
+pub extern fn transcoder_get_images_count(*BasisFile) u32;
+pub extern fn transcoder_get_levels_count(*BasisFile, image_index: u32) u32;
+pub extern fn transcoder_get_image_level_desc(
+    *BasisFile,
+    image_index: u32,
+    level_index: u32,
+    orig_width: *u32,
+    orig_height: *u32,
+    total_block: *u32,
+) bool;
+pub extern fn transcoder_get_image_transcoded_size(
+    *BasisFile,
+    image_index: u32,
+    level_index: u32,
+    format: u32,
+    size: *u32,
+) bool;
+pub extern fn transcoder_start_transcoding(*BasisFile) bool;
+pub extern fn transcoder_stop_transcoding(*BasisFile) bool;
+pub extern fn transcoder_transcode(
+    *BasisFile,
+    out: [*]const u8,
+    out_size: u32,
+    image_index: u32,
+    level_index: u32,
+    format: u32,
+    decode_flags: u32,
+    output_row_pitch_in_blocks_or_pixels: u32,
+    output_rows_in_pixels: u32,
+) bool;
diff --git a/basisu/src/transcoder/wrapper.cpp b/basisu/src/transcoder/wrapper.cpp
new file mode 100644
index 00000000..bad81c98
--- /dev/null
+++ b/basisu/src/transcoder/wrapper.cpp
@@ -0,0 +1,153 @@
+#include <basisu_transcoder.h>
+#include <cstdbool>
+#include <cstdint>
+
+extern "C" {
+void basisu_transcoder_init();
+
+bool transcoder_is_format_supported(uint32_t tex_type, uint32_t fmt);
+
+void *transcoder_init(void *src, uint32_t src_size);
+void transcoder_deinit(void *h);
+
+uint32_t transcoder_get_images_count(void *h);
+uint32_t transcoder_get_levels_count(void *h, uint32_t image_index);
+
+bool transcoder_get_image_level_desc(void *h, uint32_t image_index,
+                                     uint32_t level_index, uint32_t &orig_width,
+                                     uint32_t &orig_height,
+                                     uint32_t &block_count);
+
+bool transcoder_get_image_transcoded_size(void *h, uint32_t image_index,
+                                          uint32_t level_index, uint32_t format,
+                                          uint32_t &size);
+
+bool transcoder_start_transcoding(void *h);
+bool transcoder_stop_transcoding(void *h);
+
+bool transcoder_transcode(void *h, void *out, uint32_t out_size,
+                          uint32_t image_index, uint32_t level_index,
+                          uint32_t format, uint32_t decode_flags,
+                          uint32_t output_row_pitch_in_blocks_or_pixels,
+                          uint32_t output_rows_in_pixels);
+}
+
+void basisu_transcoder_init() { basist::basisu_transcoder_init(); }
+
+#define MAGIC 0xDEADBEE1
+
+struct basis_file {
+  int m_magic;
+  basist::basisu_transcoder m_transcoder;
+  void *m_pFile;
+  uint32_t m_file_size;
+
+  basis_file() : m_transcoder() {}
+};
+
+// transcoder_texture_format, basis_tex_format
+bool transcoder_is_format_supported(uint32_t tex_type, uint32_t fmt) {
+  return basist::basis_is_format_supported(
+      (basist::transcoder_texture_format)tex_type,
+      (basist::basis_tex_format)fmt);
+}
+
+// !null - success
+// null - validation failure
+void *transcoder_init(void *src, uint32_t src_size) {
+  auto f = new basis_file;
+  f->m_pFile = src;
+  f->m_file_size = src_size;
+
+  if (!f->m_transcoder.validate_header(f->m_pFile, f->m_file_size)) {
+    delete f;
+    return nullptr;
+  }
+  f->m_magic = MAGIC;
+
+  return f;
+}
+
+void transcoder_deinit(void *h) {
+  auto f = static_cast<basis_file *>(h);
+  delete f;
+}
+
+uint32_t transcoder_get_images_count(void *h) {
+  auto f = static_cast<basis_file *>(h);
+  return f->m_transcoder.get_total_images(f->m_pFile, f->m_file_size);
+}
+
+uint32_t transcoder_get_levels_count(void *h, uint32_t image_index) {
+  auto f = static_cast<basis_file *>(h);
+  return f->m_transcoder.get_total_image_levels(f->m_pFile, f->m_file_size,
+                                                image_index);
+}
+
+// true - success
+// false - OutOfBoundsLevelIndex
+bool transcoder_get_image_level_desc(void *h, uint32_t image_index,
+                                     uint32_t level_index, uint32_t &orig_width,
+                                     uint32_t &orig_height,
+                                     uint32_t &block_count) {
+  auto f = static_cast<basis_file *>(h);
+  return f->m_transcoder.get_image_level_desc(
+      f->m_pFile, f->m_file_size, image_index, level_index, orig_width,
+      orig_height, block_count);
+}
+
+// true - success
+// false - OutOfBoundsLevelIndex
+bool transcoder_get_image_transcoded_size(void *h, uint32_t image_index,
+                                          uint32_t level_index, uint32_t format,
+                                          uint32_t &size) {
+  auto f = static_cast<basis_file *>(h);
+  uint32_t orig_width, orig_height, total_blocks;
+  if (!f->m_transcoder.get_image_level_desc(
+          f->m_pFile, f->m_file_size, image_index, level_index, orig_width,
+          orig_height, total_blocks))
+    return false;
+
+  uint8_t bytes_per_block_or_pixel = basis_get_bytes_per_block_or_pixel(
+      (basist::transcoder_texture_format)format);
+  if (basis_transcoder_format_is_uncompressed(
+          (basist::transcoder_texture_format)format)) {
+    size = orig_width * orig_height * bytes_per_block_or_pixel;
+  } else {
+    size = total_blocks * bytes_per_block_or_pixel;
+  }
+
+  return true;
+}
+
+// true - success
+// false - unknown
+bool transcoder_start_transcoding(void *h) {
+  auto f = static_cast<basis_file *>(h);
+  return f->m_transcoder.start_transcoding(f->m_pFile, f->m_file_size);
+}
+
+// true - success
+// false - unknown
+bool transcoder_stop_transcoding(void *h) {
+  auto f = static_cast<basis_file *>(h);
+  return f->m_transcoder.stop_transcoding();
+}
+
+// true - success
+// false - unknown
+bool transcoder_transcode(void *h, void *out, uint32_t out_size,
+                          uint32_t image_index, uint32_t level_index,
+                          uint32_t format, uint32_t decode_flags,
+                          uint32_t output_row_pitch_in_blocks_or_pixels,
+                          uint32_t output_rows_in_pixels) {
+  auto f = static_cast<basis_file *>(h);
+  uint32_t bytes_per_block = basis_get_bytes_per_block_or_pixel(
+      (basist::transcoder_texture_format)format);
+
+  return f->m_transcoder.transcode_image_level(
+      f->m_pFile, f->m_file_size, image_index, level_index, out,
+      out_size / bytes_per_block, (basist::transcoder_texture_format)format,
+      decode_flags, output_row_pitch_in_blocks_or_pixels, nullptr,
+      output_rows_in_pixels);
+}
diff --git a/basisu/test/ziggy.png b/basisu/test/ziggy.png
new file mode 100644
index 00000000..5d8e470e
Binary files /dev/null and b/basisu/test/ziggy.png differ
diff --git a/basisu/upstream b/basisu/upstream
new file mode 160000
index 00000000..d55a3f9f
--- /dev/null
+++ b/basisu/upstream
@@ -0,0 +1 @@
+Subproject commit d55a3f9f06adf9cc8c31f58e894d947cc6026da5
diff --git a/build.zig b/build.zig
index 17301d4b..88e5fb58 100644
--- a/build.zig
+++ b/build.zig
@@ -6,6 +6,7 @@ const system_sdk = @import("glfw/system_sdk.zig");
 const glfw = @import("glfw/build.zig");
 const ecs = @import("ecs/build.zig");
 const freetype = @import("freetype/build.zig");
+const basisu = @import("basisu/build.zig");
 const sysaudio = @import("sysaudio/build.zig");
 const sysjs = @import("sysjs/build.zig");
 const Pkg = std.build.Pkg;
@@ -43,6 +44,7 @@ pub fn build(b: *std.build.Builder) void {
     test_step.dependOn(&glfw.testStep(b, mode, target).step);
     test_step.dependOn(&ecs.testStep(b, mode, target).step);
     test_step.dependOn(&freetype.testStep(b, mode, target).step);
+    test_step.dependOn(&basisu.testStep(b, mode, target).step);
     test_step.dependOn(&sysaudio.testStep(b, mode, target, .{}).step);
     // TODO: we need a way to test wasm stuff
     // test_mach_step.dependOn(&sysjs.testStep(b, mode, target).step);