Configuration and profiles

Configuration and profiles

src/config.cpp, src/config.h, src/json.cpp

Where it lives

CapView.json, beside the executable. Nothing is written to the registry — the one exception being the virtual camera's COM registration, which has to be machine-wide and is not CapView's own setting. See Virtual camera.

The JSON parser and writer are hand-written (src/json.cpp, 450 lines) rather than pulled in as a dependency. The file is small, the schema is known, and every read goes through a defaulting accessor:

app.settingsTab = a["settingsTab"].AsInt(0);

A missing or malformed key yields the default instead of an error, so a config file from an older build always loads.

Profiles

struct Profile {
  std::string name = "Standard";
  CaptureSettings capture;   // device, input, format, video standard
  ImageSettings image;       // scaling, deinterlacing, composite filter, crop, colour
  AudioSettings audio;       // devices, buffer, offset, volume, microphone
};

One per source. Selected with Ctrl+1 to Ctrl+9, which is deliberately not rebindable — see Shortcuts.

A profile is everything that depends on what is plugged in. Switching profiles restarts the capture graph, because the device or the format may have changed.

What is not in a profile — AppSettings — is everything that depends on you: theme, accent colour, language, vsync, always-on-top, cursor hiding, sleep prevention, the toolbar, the overlay level, where the settings window sits, which tab it was on, and every recording, encoder and update setting.

Settings that change meaning

Two places in the configuration carry an index into a table rather than a value, and both are noted in the source at the table:

• videoStandard — the index into kStandards in src/capture/dshow_util.cpp. Entries may be appended but never reordered.
• speed — the old software encoder speed, kept working alongside the newer preset setting so nobody's existing configuration changes meaning. See Encoder settings.

Sleep prevention

preventSleep, on by default. Playing a game through a capture card involves no keyboard or mouse input as far as Windows is concerned, so the screen saver would come on mid-session. App calls SetThreadExecutionState periodically while a capture is running.

The shader cache

Not configuration, but it lives in the same folder and is worth knowing about.

Compiled shaders are cached as shader-<hash>.cso next to the executable, keyed by an FNV-1a hash of the source text and the compile target. That is what keeps startup fast — the composite filter alone takes seconds to compile.

PruneShaderCache() runs at startup and deletes every shader-*.cso that is not in the list this build actually uses:

for (const std::wstring& used : ShaderCacheInUse()) { … }
if (!live && ::DeleteFileW(path.c_str())) ++removed;

A failed delete is not an error — if a second instance is holding the file, the next start gets another turn.

Without this, every shader edit in every build left its cache file behind forever.