From e82b119b3646b992e6cb903f82ef4ea2ab6ea314 Mon Sep 17 00:00:00 2001
From: Emil Lerch <emil@lerch.org>
Date: Wed, 29 Oct 2025 17:25:59 -0700
Subject: [PATCH] add silence threshold for great good

---
 src/main.zig | 21 +++++++++++++++++----
 src/stt.zig  |  8 +++++++-
 2 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index 5e932de..5be549c 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -418,6 +418,7 @@ pub fn main() !void {
     var model_path: ?[]const u8 = null;
     var exec_program: ?[]const u8 = null;
     var measure_levels = false;
+    var silence_threshold: ?i16 = null;
 
     // Parse arguments
     for (args[1..]) |arg| {
@@ -426,10 +427,11 @@ pub fn main() !void {
             _ = try stdout.writeAll("USAGE:\n");
             _ = try stdout.writeAll("    stt [OPTIONS]\n\n");
             _ = try stdout.writeAll("OPTIONS:\n");
-            _ = try stdout.writeAll("    --model=<path>       Path to Vosk model directory\n");
-            _ = try stdout.writeAll("    --exec=<program>     Program to execute with recognized text\n");
-            _ = try stdout.writeAll("    --measure-levels     Display real-time audio level histogram\n");
-            _ = try stdout.writeAll("    --help, -h           Show this help message\n\n");
+            _ = try stdout.writeAll("    --model=<path>            Path to Vosk model directory\n");
+            _ = try stdout.writeAll("    --exec=<program>          Program to execute with recognized text\n");
+            _ = try stdout.writeAll("    --silence-threshold=<n>   Silence detection threshold (default: 300)\n");
+            _ = try stdout.writeAll("    --measure-levels          Display real-time audio level histogram\n");
+            _ = try stdout.writeAll("    --help, -h                Show this help message\n\n");
             _ = try stdout.writeAll("EXAMPLES:\n");
             _ = try stdout.writeAll("    stt\n");
             _ = try stdout.writeAll("    stt --model=../share/vosk/models/vosk-model-small-en-us-0.15\n");
@@ -445,6 +447,16 @@ pub fn main() !void {
             exec_program = arg[7..]; // Skip "--exec="
         } else if (std.mem.eql(u8, arg, "--measure-levels")) {
             measure_levels = true;
+        } else if (std.mem.startsWith(u8, arg, "--silence-threshold=")) {
+            const threshold_str = arg[20..]; // Skip "--silence-threshold="
+            silence_threshold = std.fmt.parseInt(i16, threshold_str, 10) catch {
+                std.log.err("Invalid silence threshold: {s}", .{threshold_str});
+                return error.InvalidArgument;
+            };
+            if (silence_threshold.? < 0) {
+                std.log.err("Invalid silence threshold: {s}", .{threshold_str});
+                return error.InvalidArgument;
+            }
         }
     }
 
@@ -516,6 +528,7 @@ pub fn main() !void {
         .event_handler = speech_handler,
         .sample_rate = 16000, // Standard sample rate for speech recognition
         .buffer_size = 256, // Existing buffer size for low latency
+        .silence_threshold = silence_threshold orelse 300,
     };
 
     std.log.debug("Initializing STT library...", .{});
diff --git a/src/stt.zig b/src/stt.zig
index 48e744d..a268a57 100644
--- a/src/stt.zig
+++ b/src/stt.zig
@@ -606,6 +606,8 @@ pub const Options = struct {
     // channels: u32 = 2,
     /// Audio buffer size in frames (default: 256)
     buffer_size: u32 = 256,
+    /// Silence detection threshold (default: 300)
+    silence_threshold: i16 = 300,
 };
 
 /// Main STT session handle
@@ -970,11 +972,15 @@ pub const Session = struct {
         defer self.allocator.free(vosk_buffer);
 
         // Silence detection parameters
-        const silence_threshold: i16 = 300;
+        const silence_threshold: i16 = self.options.silence_threshold;
         const silence_duration_ms: u64 = 500;
         const min_speech_duration_ms: u64 = 300;
         const samples_per_ms = 16; // This assumes 16kHz audio
 
+        std.log.info(
+            "Listening with silence threshold {}. If wrong, use --measure-levels to find approriate val",
+            .{silence_threshold},
+        );
         var speech_buffer = self.allocator.alloc(i16, 16000 * 10) catch {
             const error_info = ErrorInfo.init(Error.OutOfMemory, "Failed to allocate speech buffer");
             self.options.event_handler.onDetailedError(error_info);