phase4: Linux native_bridge build (Docker) — sfizz from source, --render SF2/SFZ

- Dockerfile: build sfizz tu native_bridge/sfizz-src (hoac git clone v1.2.3), sed fix sfizz.pc (-llibsfizz -> -lsfizz), cmake bridge voi 3 flag SMTG OFF (VSTGUI/plugin/hosting examples) — bridge headless chi can --render. - CMakeLists: nhanh non-WIN32 build daw_vst_bridge tu main_linux.cpp + RenderJob.cpp + NativeInstrumentEngine.cpp (SF2/SF3 + SFZ; VST3/VST2 hosting Windows-only, guard #ifdef _WIN32). gui_probe/plugin_host/ seh_channel_test chi build tren Windows. - RenderJob.cpp: JSON parser (sheredom json.h) khong con phu thuoc HAVE_VST3SDK — render SF2/SFZ chay duoc khong can VST3 SDK. - NativeInstrumentEngine.cpp: guard windows.h/VST3/VST2/Sandbox/SEH. - main.cpp: g_engine unconditional + guard disable_ime_contexts (_WIN32). - engine.spec: bo pedalboard collect_dynamic_libs + hidden imports. - vst_engine/render_engine: DecentSampler -> NotImplementedError + huong dan convert .dspreset -> .vstpreset; pianobook fallback synth. - Verified: WSL Ubuntu 24.04 build OK, bridge Linux --render SF2 ra WAV 44100 stereo peak 1575; Python tests 115 passed 1 skipped. - Dockerfile build chua test duoc (may khong co Docker).
2026-08-17 11:46:24 +07:00
parent efe26e3277
commit e79dae5d5c
10 changed files with 135 additions and 71 deletions
@@ -37,6 +37,33 @@ RUN pip install --no-cache-dir -r requirements.txt

 COPY . .

+# ── Build native_bridge (Linux) — thay pedalboard GPL-3.0 ──────────────────
+# Xem PLAN_REPLACE_PEDALBOARD_NATIVE_BRIDGE.md §4. sfizz khong co trong apt
+# Debian → build tu nguon vendored (native_bridge/sfizz-src, co trong build
+# context) hoac git clone fallback khi thieu. Bridge chay --render duoi
+# Xvfb :99 (DISPLAY da set o tren) — khong can GUI plugin editor.
+RUN apt-get update && apt-get install -y --no-install-recommends \
+        cmake pkg-config libfluidsynth-dev libfreetype-dev git \
+    && rm -rf /var/lib/apt/lists/* \
+    && if [ -d native_bridge/sfizz-src ]; then cp -r native_bridge/sfizz-src /tmp/sfizz; \
+       else git clone --recursive --depth 1 --branch v1.2.3 https://github.com/sfztools/sfizz.git /tmp/sfizz; fi \
+    && cmake -S /tmp/sfizz -B /tmp/sfizz/build -DCMAKE_BUILD_TYPE=Release \
+           -DSFIZZ_SHARED=ON -DSFIZZ_JACK=OFF -DSFIZZ_RENDER=OFF -DSFIZZ_TESTS=OFF \
+           -DSFIZZ_BENCHMARKS=OFF -DSFIZZ_DEMOS=OFF -DSFIZZ_DEVTOOLS=OFF \
+           -DSFIZZ_GIT_SUBMODULE_CHECK=OFF -DBUILD_TESTING=OFF \
+    && cmake --build /tmp/sfizz/build --target sfizz_shared -j"$(nproc)" \
+    && cmake --install /tmp/sfizz/build \
+    && sed -i 's/-llibsfizz/-lsfizz/' /usr/local/lib/pkgconfig/sfizz.pc \
+    && cmake -S native_bridge -B /tmp/bridge-build -DCMAKE_BUILD_TYPE=Release \
+           -DSMTG_ENABLE_VST3_PLUGIN_EXAMPLES=OFF \
+           -DSMTG_ENABLE_VST3_HOSTING_EXAMPLES=OFF \
+           -DSMTG_ENABLE_VSTGUI_SUPPORT=OFF \
+    && cmake --build /tmp/bridge-build --target daw_vst_bridge -j"$(nproc)" \
+    && mkdir -p /app/install \
+    && cp /tmp/bridge-build/daw_vst_bridge /app/install/ \
+    && rm -rf /tmp/sfizz /tmp/sfizz/build /tmp/bridge-build
+
+
 # Copy VST3 plugins if present
 COPY ./vst_plugins/ /opt/daw_engine/vst3/

@@ -1,8 +1,7 @@
 # PLAN: thay pedalboard (GPL-3.0) bằng native_bridge — render VSTi offline

 Ngày: 2026-08-15
-Trạng thái: Phase 2 xong (app/core/native_render.py client spawn bridge --render; plugins.py preview + /midi-render dùng bridge khi SF_RENDER_ENGINE=bridge; velocity float 0..1 đã fix double-scaling; bank/program parity; golden test bridge vs pedalboard RMS; test Python 111 pass 1 skip, C++ 20/20). Windows sửa code bridge/desktop;
-Linux làm bridge Linux + Docker + test so sánh.
+Trạng thái: Phase 4 xong (engine.spec bỏ pedalboard; DecentSampler → hướng dẫn convert .dspreset→.vstpreset; Dockerfile build native_bridge Linux — sfizz build từ nguồn + sed fix sfizz.pc + bridge --render SF2/SFZ; Linux port: CMakeLists nhánh non-WIN32, main_linux.cpp, guard Windows-only NativeInstrumentEngine.cpp/RenderJob.cpp; verified WSL Ubuntu 24.04 — bridge Linux render SF2 ra WAV 44100 stereo peak 1575; test Python 115 pass 1 skip). Phase 5 còn lại: đảo flag mặc định bridge, gỡ pedalboard khỏi requirements/source, LICENSE.

 ## 1. Mục tiêu
 Xóa dependency GPL-3.0 (`pedalboard`) khỏi cả 2 môi trường, chuyển toàn bộ
@@ -7,7 +7,6 @@ from app.config import settings
 from app.core.vst_engine import (
    render_midi_events_to_audio,
    PluginManager,
-    DecentSamplerManager,
    HAS_PEDALBOARD,
    HAS_PYFLUIDSYNTH,
    apply_preset_to_plugin,
@@ -204,35 +203,16 @@ class PythonRenderEngine:
                            vst = plugin_mgr.load_vst(instrument_id) if instrument_id else None

                            if instrument_source == "pianobook":
+                                # Phase 4 (§3.4): .dspreset không hỗ trợ nữa (pedalboard
+                                # GPL-3.0 gỡ; spike load .dspreset fail). Chặn + fallback synth.
                                dspreset_path = track.get("dspreset_path", "")
-                                if dspreset_path and os.path.exists(dspreset_path) and HAS_PEDALBOARD:
-                                    from pedalboard import Pedalboard
-                                    ds_manager = DecentSamplerManager()
-                                    try:
-                                        vst = ds_manager.create_decent_sampler_instance(dspreset_path)
-                                        midi_messages = PluginManager.midi_events_to_messages(
-                                            midi_events, bpm, self.sample_rate
-                                        )
-                                        total_needed = 0
-                                        for ev in midi_events:
-                                            end_sec = (ev.get("start_beat", 0) + ev.get("duration_beats", 1)) * (60.0 / bpm)
-                                            dur_samples = int(end_sec * self.sample_rate)
-                                            if dur_samples > total_needed:
-                                                total_needed = dur_samples
-                                        total_needed = max(total_needed, 1024)
-                                        silent = np.zeros((2, total_needed), dtype=np.float32)
-                                        # pedalboard >= 0.9: instrument KHÔNG vào Pedalboard container
-                                        synth_buffer = vst(midi_messages, sample_rate=self.sample_rate,
-                                                           duration=total_needed / float(self.sample_rate), num_channels=2)
-                                    except Exception as e:
-                                        logger.warning(f"[RenderEngine] DecentSampler/Pianobook error: {e}")
-                                        synth_buffer = render_midi_events_to_audio(
-                                            midi_events=midi_events, sr=self.sample_rate, bpm=bpm, instrument='synth'
-                                        )
-                                else:
-                                    synth_buffer = render_midi_events_to_audio(
-                                        midi_events=midi_events, sr=self.sample_rate, bpm=bpm, instrument='synth'
-                                    )
+                                logger.warning(
+                                    "[RenderEngine] Pianobook track bỏ qua: .dspreset không còn hỗ trợ. "
+                                    "Convert sang .vstpreset (DecentSampler → Save preset) rồi gán lại track."
+                                )
+                                synth_buffer = render_midi_events_to_audio(
+                                    midi_events=midi_events, sr=self.sample_rate, bpm=bpm, instrument='synth'
+                                )
                            elif instrument_id and not instrument_id.startswith("sf_"):
                                # VSTi track: native_bridge --render (SF_RENDER_ENGINE=bridge)
                                # thay pedalboard; ngược lại giữ pedalboard path cũ.
@@ -521,25 +521,15 @@ class DecentSamplerManager:
        self.vst_path = vst_path

    def create_decent_sampler_instance(self, dspreset_path: str):
-        if not HAS_PEDALBOARD:
-            raise RuntimeError("pedalboard not available")
-        if not os.path.exists(self.vst_path):
-            raise FileNotFoundError(f"DecentSampler VST3 not found at {self.vst_path}")
-        if not os.path.exists(dspreset_path):
-            raise FileNotFoundError(f"Preset file not found at {dspreset_path}")
-
-        plugin = VST3Plugin(self.vst_path)
-
-        abs_preset = os.path.abspath(dspreset_path)
-        preset_dir = os.path.dirname(abs_preset)
-        cwd_before = os.getcwd()
-        try:
-            os.chdir(preset_dir)
-            plugin.load_preset(abs_preset)
-        finally:
-            os.chdir(cwd_before)
-
-        return plugin
+        # Phase 4 (PLAN_REPLACE_PEDALBOARD_NATIVE_BRIDGE.md §3.4): .dspreset là
+        # format riêng của DecentSampler (không phải VST3 state) — spike đã fail
+        # cả trên pedalboard (container: "failed to load data from preset file").
+        # pedalboard GPL-3.0 bị gỡ → chặn Pianobook + hướng dẫn convert.
+        raise NotImplementedError(
+            "Pianobook .dspreset không còn được hỗ trợ (pedalboard GPL-3.0 đã gỡ). "
+            "Chuyển đổi: mở preset trong DecentSampler → save .vstpreset (VST3 state) "
+            "rồi upload .vstpreset qua web UI — native_bridge đọc được."
+        )


 # ── Preset bridge (Carla ↔ pedalboard) ─────────────────────────────────────
@@ -5,9 +5,8 @@
 import os
 from PyInstaller.utils.hooks import collect_dynamic_libs, collect_data_files

-# Native DLL cho pedalboard va soundfile (Windows .pyd/.dll, Linux .so)
-binaries = collect_dynamic_libs('pedalboard')
-binaries += collect_dynamic_libs('soundfile')
+# Native DLL cho soundfile (Windows .pyd/.dll, Linux .so)
+binaries = collect_dynamic_libs('soundfile')

 # Root tuyet doi cua thu muc chua spec — dung cho cac datas KHONG nam trong
 # package 'app' (vd thu muc md/). Cac assets cua app (static/templates/models)
@@ -89,12 +88,7 @@ _hidden = [
    'uvicorn.protocols.http.auto',
    'uvicorn.protocols.websockets',
    'uvicorn.protocols.websockets.auto',
-    'pedalboard',
-    # C++ ExternalPlugin.h import pedalboard.midi_utils khi tao VST3Plugin
-    # (py::module_::import) - PyInstaller khong thay duoc import tu C++, phai
-    # khai bao hiddenimport thu cong (thieu -> "No module named
-    # 'pedalboard.midi_utils'" khi /midi-render).
-    'pedalboard.midi_utils',
+    # pedalboard (GPL-3.0) DA XOA — native_bridge thay the (xem PLAN_REPLACE_PEDALBOARD_NATIVE_BRIDGE.md)
    'soundfile',
    'sf2utils',
    # pyfluidsynth (fluidsynth.py cffi) - render soundfont native cho
@@ -8,11 +8,11 @@ if(MSVC)
 endif()

 # ── 1. VST3 SDK (Steinberg, vendored as git submodule — NOT in vcpkg) ──
-if(EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/vst3sdk/CMakeLists.txt")
+if(WIN32 AND EXISTS "${CMAKE_CURRENT_SOURCE_DIR}/vst3sdk/CMakeLists.txt")
  add_subdirectory(vst3sdk EXCLUDE_FROM_ALL)
  set(VST3_SDK_TARGET sdk)
 else()
-  message(WARNING "vst3sdk submodule missing — VST3 host disabled; SF2/SF3/SFZ still build")
+  message(STATUS "vst3sdk build skipped (Windows-only) — VST3 host disabled; SF2/SF3/SFZ still build")
  set(VST3_SDK_TARGET "")
 endif()

@@ -54,6 +54,7 @@ include_directories(
  ${SFIZZ_INCLUDE_DIR}
 )

+if(WIN32)
 add_executable(daw_vst_bridge
  src/main.cpp
  src/RenderJob.cpp
@@ -64,6 +65,15 @@ add_executable(daw_vst_bridge
  src/StateStore.cpp
        src/SandboxVst3Host.cpp
 )
+else()
+# Linux: offline --render only (SF2/SF3 + SFZ; VST3/VST2 hosting is
+# Windows-only). main_linux.cpp is the tiny --render entry.
+add_executable(daw_vst_bridge
+  src/main_linux.cpp
+  src/RenderJob.cpp
+  src/NativeInstrumentEngine.cpp
+)
+endif()

 # VST3 SDK hosting: sdk_hosting lacks the platform module loader — module_win32.cpp
 # is added to the bridge itself (same approach as the audiohost sample).
@@ -86,6 +96,7 @@ else()
 endif()

 # ── gui_probe: standalone VST3 GUI attach probe (debug tool, not shipped) ──
+if(WIN32)
 add_executable(gui_probe
  src/gui_probe.cpp
  src/NativeInstrumentEngine.cpp
@@ -147,3 +158,4 @@ endif()
 if(WIN32)
  target_link_libraries(seh_channel_test PRIVATE ${FLUIDSYNTH_LIBRARY} ${SFIZZ_LIBRARY} winmm)
 endif()
+endif()  # WIN32-only debug tools (gui_probe, plugin_host, seh_channel_test)
@@ -3,15 +3,19 @@

 #include <fluidsynth.h>
 #include <sfizz.hpp>
+#ifdef _WIN32
 #include "Vst3Instrument.h"
 #include "Vst2Instrument.h"
 #include "SandboxVst3Host.h"
+#endif

 // void* members keep fluid types out of the public header; cast here.
 #define FS_SYNTH (static_cast<fluid_synth_t*>(synth))
 #define FS_SETTINGS (static_cast<fluid_settings_t*>(settings))

+#ifdef _WIN32
 #include <windows.h>
+#endif

 #include <algorithm>
 #include <cctype>
@@ -168,6 +172,7 @@ std::unique_ptr<INativeInstrument> InstrumentEngineManager::create_instrument(In
    switch (type) {
        case InstrumentType::SOUNDFONT_SF2_SF3: return std::make_unique<FluidSynthInstrument>();
        case InstrumentType::SFZ:                return std::make_unique<SfizzInstrument>();
+#ifdef _WIN32
        case InstrumentType::VST3:
            // G4.2: SF_SANDBOX_VST3=1 -> host the VST3 in a child
            // process (plugin_host.exe). Crash kills only the child.
@@ -176,6 +181,13 @@ std::unique_ptr<INativeInstrument> InstrumentEngineManager::create_instrument(In
            return std::make_unique<Vst3Instrument>();
        case InstrumentType::VST2:
            return std::make_unique<Vst2Instrument>();
+#else
+        case InstrumentType::VST3:
+        case InstrumentType::VST2:
+            // Linux bridge: SF2/SF3 + SFZ only (Docker render). VST3/VST2
+            // hosting is Windows-only (COM/HWND/SHM realtime loop).
+            return nullptr;
+#endif
        default:                                 return nullptr;
    }
 }
@@ -191,6 +203,7 @@ bool InstrumentEngineManager::assign(uint32_t channel, InstrumentType type,
        loaded = static_cast<FluidSynthInstrument*>(inst.get())->loadSoundFontFile(path, sampleRate);
    else if (type == InstrumentType::SFZ)
        loaded = static_cast<SfizzInstrument*>(inst.get())->loadSfzFile(path, sampleRate);
+#ifdef _WIN32
    else if (type == InstrumentType::VST3) {
        if (auto* v = dynamic_cast<Vst3Instrument*>(inst.get()))
            loaded = v->loadPlugin(path, sampleRate);
@@ -207,6 +220,7 @@ bool InstrumentEngineManager::assign(uint32_t channel, InstrumentType type,
        if (auto* v = dynamic_cast<Vst3Instrument*>(inst.get()))
            v->setChannel(channel);
    }
+#endif
    if (!loaded) return false;
    // init() AFTER load: FluidSynth creates its synth inside loadSoundFontFile.
    if (!inst->init(sampleRate, blockSize)) return false;
@@ -415,8 +429,11 @@ static float* alignF(std::vector<float>& v, size_t n) {
 // (0xC0000005) is caught here — the channel is muted instead of killing the
 // whole bridge process. /EHa (set in CMakeLists) allows mixing with the
 // outer C++ try/catch net in main.cpp.
+#ifdef _WIN32
 static DWORD g_sehCode = 0;
 static void* g_sehAddr = nullptr;
+#endif
+#ifdef _WIN32
 static bool SafeProcessChannel(INativeInstrument* inst, float* outL, float* outR, uint32_t n, DWORD* outCode) {
    *outCode = 0;
    __try {
@@ -429,6 +446,18 @@ static bool SafeProcessChannel(INativeInstrument* inst, float* outL, float* outR
        return false;
    }
 }
+#else
+static bool SafeProcessChannel(INativeInstrument* inst, float* outL, float* outR, uint32_t n, uint32_t* outCode) {
+    *outCode = 0;
+    try {
+        inst->processAudioBlock(outL, outR, n);
+        return true;
+    } catch (...) {
+        *outCode = 1;
+        return false;
+    }
+}
+#endif

 void InstrumentEngineManager::renderAll(float* outputL, float* outputR, uint32_t numSamples) {
    if (isBypassed_.load()) {
@@ -446,11 +475,12 @@ void InstrumentEngineManager::renderAll(float* outputL, float* outputR, uint32_t
        float* spR = alignF(scratchR_, numSamples);
        std::memset(spL, 0, numSamples * sizeof(float));
        std::memset(spR, 0, numSamples * sizeof(float));
-        DWORD sehCode = 0;
+        uint32_t sehCode = 0;
        if (!SafeProcessChannel(inst.get(), spL, spR, numSamples, &sehCode)) {
            // G3.3: plugin fault — mute this channel only, keep the bridge up.
            if (!crashedCh_[ch]) {
                crashedCh_[ch] = true;
+#ifdef _WIN32
                {
                    HMODULE m = nullptr;
                    char mod[MAX_PATH] = "?";
@@ -477,6 +507,11 @@ void InstrumentEngineManager::renderAll(float* outputL, float* outputR, uint32_t
                    }
                    std::cerr << std::endl;
                }
+#else
+                std::cerr << "[NativeBridge] G3.3: channel " << ch
+                          << " plugin crashed in processAudioBlock — muted until reload"
+                          << std::endl;
+#endif
            }
            continue;
        }
@@ -9,8 +9,10 @@
 #include "RenderJob.h"
 #include "NativeInstrumentEngine.h"

-#ifdef HAVE_VST3SDK
+// sheredom/json.h (public domain, vendored with the VST3 SDK) is header-only
+// and needed for SF2/SFZ render even without the VST3 SDK — include it directly.
 #include "vst3sdk/public.sdk/source/vst/moduleinfo/json.h"
+#ifdef HAVE_VST3SDK
 #include "public.sdk/source/vst/vstpresetfile.h"
 #include "public.sdk/source/common/memorystream.h"
 using Steinberg::int32;
@@ -37,7 +39,6 @@ using Steinberg::uint32;

 namespace {

-#ifdef HAVE_VST3SDK
 // --- sheredom/json.h helpers -------------------------------------------------
 const json_object_element_s* member(const json_object_s* o, const char* key) {
    for (const json_object_element_s* e = o ? o->start : nullptr; e; e = e->next)
@@ -73,7 +74,6 @@ int64_t memberInt(const json_object_s* o, const char* key, int64_t def) {
    double d;
    return memberNumber(o, key, d) ? (int64_t)d : def;
 }
-#endif // HAVE_VST3SDK

 // --- WAV writer (stdlib only, 16-bit PCM stereo, little-endian) --------------
 void writeU16(std::ofstream& f, uint16_t v) {
@@ -247,10 +247,6 @@ int run_render_job(const std::string& jobPath, const std::string& outPath) {
        std::remove(outPath.c_str());  // never leave a partial clip behind
    };

-#ifndef HAVE_VST3SDK
-    fail("built without the VST3 SDK submodule — JSON parser unavailable, --render disabled");
-    return rc;
-#else
    struct RootHolder { json_value_s* p = nullptr; ~RootHolder() { if (p) std::free(p); } } rootH;

    // 1. Read + parse the job.
@@ -347,12 +343,18 @@ int run_render_job(const std::string& jobPath, const std::string& outPath) {
        if (type != InstrumentType::VST3) {
            std::cerr << "[RenderJob] preset ignored for non-VST3 type " << (int)type
                      << " (SF2/SFZ use soundfont_bank/soundfont_program)" << std::endl;
+#ifdef HAVE_VST3SDK
        } else if (!applyVst3Preset(mgr.get(0), preset)) {
            fail("preset import FAILED for " + pluginPath);
            return rc;  // rc stays 1: job/argument error
        } else {
            std::cout << "[RenderJob] preset imported (VST3 .vstpreset) type=" << (int)type << std::endl;
        }
+#else
+        } else {
+            std::cerr << "[RenderJob] preset ignored: built without VST3 SDK" << std::endl;
+        }
+#endif
    }

    // 6. Offline render loop — same dispatch/render split as the realtime
@@ -404,5 +406,4 @@ int run_render_job(const std::string& jobPath, const std::string& outPath) {
              << " samples, " << (dataBytes / 4) << " frames)" << std::endl;
    rc = 0;
    return rc;
-#endif // HAVE_VST3SDK
 }
@@ -110,7 +110,7 @@ class ChannelWorker;  // fwd — WM_DESTROY posts closeGUI() to the channel work
 static void post_close_gui(uint32_t ch, HWND hwnd);  // defined after ChannelWorker
 static void post_resize_view(uint32_t ch, int w, int h);  // defined after ChannelWorker

-static InstrumentEngineManager* g_engine = nullptr;
+static InstrumentEngineManager* g_engine = nullptr;  // declared unconditionally (Linux --render build needs the symbol)
 static std::mutex g_guiMutex;
 static std::map<uint32_t, void*> g_guiWindows;  // channel -> HWND (keep window alive)
 static std::map<HWND, uint32_t> g_hwndToCh;     // HWND -> channel (WM_DESTROY cleanup)
@@ -1010,7 +1010,9 @@ int main(int argc, char* argv[]) {
                        // a JUCE_ window + plugin wndproc (ImmIsUIMessageW ->
                        // SendMessageW WM_IME_SETCONTEXT same hwnd) = infinite
                        // recursion (0xC00000FD, observed inside attachView).
+#ifdef _WIN32
                        if (ok) disable_ime_contexts((HWND)hwnd);
+#endif
                        if (ok) ok = inst->attachView(hwnd);
                    } catch (...) {
                        std::cerr << "[NativeBridge] GUI attach EXCEPTION ch=" << guiCh
@@ -1033,7 +1035,9 @@ int main(int argc, char* argv[]) {
                    unmute_if_not_closing(y, "openGUI");
                if (ok) {

+#ifdef _WIN32
                    disable_ime_contexts((HWND)hwnd);
+#endif

                    std::cout << "[NativeBridge] GUI attached hwnd=" << hwnd
                              << " plugin=" << arg2 << " ch=" << guiCh
@@ -0,0 +1,22 @@
+// native_bridge/src/main_linux.cpp
+// Linux entry point of daw_vst_bridge: offline --render only (Docker).
+// The Windows realtime SHM loop / VST3 GUI hosting is Windows-only and is
+// not built here. See main.cpp for the full Windows entry.
+#include "RenderJob.h"
+
+#include <cstring>
+#include <iostream>
+#include <string>
+
+int main(int argc, char* argv[]) {
+    std::string renderJob, renderOut;
+    for (int i = 1; i < argc; ++i) {
+        if (std::strcmp(argv[i], "--render") == 0 && i + 1 < argc) renderJob = argv[i + 1];
+        else if (std::strcmp(argv[i], "--out") == 0 && i + 1 < argc) renderOut = argv[i + 1];
+    }
+    if (renderJob.empty() || renderOut.empty()) {
+        std::cerr << "usage: daw_vst_bridge --render <job.json> --out <clip.wav>" << std::endl;
+        return 1;
+    }
+    return run_render_job(renderJob, renderOut);
+}