CSDK-2834 fix custom audio tracks with silence

Author: aconchillo

CHANGELOG.md

@@ -5,6 +5,14 @@ All notable changes to the **daily-python** SDK will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- Fixed an issue where custom audio tracks won't send silence from the very
+  beginning. This is necessary to avoid issues with browsers that expect RTP
+  packets form the very beginning.
+
 ## [0.19.8] - 2025-08-27
 
 ### Fixed

src/media/custom_audio_source.rs

@@ -44,7 +44,12 @@ impl PyCustomAudioSource {
 impl PyCustomAudioSource {
     #[new]
     pub fn new(sample_rate: u32, channels: u8) -> Self {
-        let audio_source_ptr = unsafe { daily_core_context_create_custom_audio_source() };
+        let audio_source_ptr = unsafe {
+            daily_core_context_create_custom_audio_source_with_silence(
+                sample_rate as i32,
+                channels as usize,
+            )
+        };
 
         let audio_source = NativeDailyAudioSource::from(audio_source_ptr);