rather large commit, it now handles memory and threading properly.

---

more thorough commit message which was generated by the wonderful copilot AI tool:

Refactor and enhance audio encoding and decoding pipelines

- Introduced CodecUtils.h for utility functions related to audio codec selection, including sample format and bitrate clamping.
- Added DecoderPipeline.h to manage audio decoding, including opening files and retrieving audio stream information.
- Implemented EncoderPipeline.h to handle audio encoding, including encoder setup, resampling, and writing output files.
- Created OutputPathBuilder.h to generate output file paths based on reencode job specifications.
- Refactored SpectrogramWidget to improve OpenGL handling and ensure safe context usage.
- Updated ReencodeDialog.h to enhance code readability and maintainability.
- Improved error handling and logging throughout the audio processing components.

CMakeLists.txt

@@ -4,6 +4,7 @@ set(CMAKE_CXX_STANDARD 20)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_AUTOMOC ON)
 set(CMAKE_AUTORCC ON)
+
 # dependencies
 find_package(Qt6 REQUIRED COMPONENTS
     Core Widgets Multimedia OpenGL OpenGLWidgets
@@ -16,6 +17,7 @@ pkg_check_modules(FFMPEG REQUIRED IMPORTED_TARGET
     libswresample
 )
 pkg_check_modules(FFTW REQUIRED IMPORTED_TARGET fftw3)
+
 # sources
 set(SOURCES
     src/main.cpp
@@ -55,6 +57,7 @@ set(SOURCES
     # reencode
     src/gui/ReencodeDialog.cpp
 )
+
 set(HEADERS
     src/config/Config.h
     src/gui/CoverArtWidget.h
@@ -84,6 +87,10 @@ set(HEADERS
     src/engine/encoder/StageBuffer.h
     src/engine/encoder/FfmpegGuards.h
     src/engine/encoder/SampleRateUtils.h
+    src/engine/encoder/CodecUtils.h        # new: pickSampleFormat/pickChannelCount/clampBitrate/ChannelLayoutGuard
+    src/engine/encoder/OutputPathBuilder.h # new: buildOutputPath
+    src/engine/encoder/DecoderPipeline.h   # new: input open + decoder context
+    src/engine/encoder/EncoderPipeline.h   # new: encoder + muxer + SWR + encode frame
     # ffmpeg wrapper
     src/engine/ffmpeg/FormatContext.h
     src/engine/ffmpeg/CodecContext.h
@@ -97,33 +104,39 @@ set(HEADERS
     # reencode
     src/gui/ReencodeDialog.h
 )
+
 # qrc resources
 set(RESOURCES
     src/shaders.qrc
     src/application.qrc
 )
+
 # target
 add_executable(SubWave ${SOURCES} ${HEADERS} ${RESOURCES})
+
 if(NOT CMAKE_BUILD_TYPE AND NOT CMAKE_CONFIGURATION_TYPES)
     message(STATUS "Setting build type to 'RelWithDebInfo' as none was specified.")
     set(CMAKE_BUILD_TYPE "RelWithDebInfo" CACHE STRING "Choose the type of build." FORCE)
 endif()
+
 if(MSVC)
     target_compile_options(SubWave PRIVATE /O2 /fp:fast)
 else()
     target_compile_options(SubWave PRIVATE -O3 -ffast-math -march=native)
 endif()
+
 # headers
 target_include_directories(SubWave PRIVATE
     src
     src/config
     src/controllers
     src/engine
-    src/engine/encoder
+    src/engine/encoder   # covers CodecUtils.h, OutputPathBuilder.h, DecoderPipeline.h, EncoderPipeline.h
     src/engine/ffmpeg
     src/playlists
     src/gui
 )
+
 # link to qt and ffmpeg and fftw
 target_link_libraries(SubWave PRIVATE
     Qt6::Core
@@ -134,6 +147,7 @@ target_link_libraries(SubWave PRIVATE
     PkgConfig::FFMPEG
     PkgConfig::FFTW
 )
+
 # For windows stupid ahh
 if(WIN32)
     set_target_properties(SubWave PROPERTIES WIN32_EXECUTABLE TRUE)