From bad29939851d91ae3c89e81c68a51fc2ce503447 Mon Sep 17 00:00:00 2001
From: thexai <58434170+thexai@users.noreply.github.com>
Date: Sat, 20 Jan 2024 11:16:11 +0100
Subject: [FileCache] adjust Read Factor algorithm

Fixes cache not fills with high bitrate files and "low" read factors.
---
 xbmc/filesystem/FileCache.cpp | 16 +++++++++++++---
 xbmc/filesystem/FileCache.h   |  4 ++++
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/xbmc/filesystem/FileCache.cpp b/xbmc/filesystem/FileCache.cpp
index b872466905..6e28deca19 100644
--- a/xbmc/filesystem/FileCache.cpp
+++ b/xbmc/filesystem/FileCache.cpp
@@ -24,7 +24,6 @@
 
 #include <algorithm>
 #include <cassert>
-#include <chrono>
 #include <inttypes.h>
 #include <memory>
 
@@ -33,7 +32,6 @@
 #endif
 
 using namespace XFILE;
-using namespace std::chrono_literals;
 
 class CWriteRate
 {
@@ -300,7 +298,7 @@ void CFileCache::Process()
       if (limiter.Rate(m_writePos) < m_writeRate * readFactor)
         break;
 
-      if (m_seekEvent.Wait(100ms))
+      if (m_seekEvent.Wait(m_processWait))
       {
         if (!m_bStop)
           m_seekEvent.Set();
@@ -618,6 +616,18 @@ int CFileCache::IoControl(EIoControl request, void* param)
   if (request == IOCTRL_CACHE_SETRATE)
   {
     m_writeRate = *static_cast<uint32_t*>(param);
+
+    const double mBits = m_writeRate / 1024.0 / 1024.0 * 8.0; // Mbit/s
+
+    // calculates wait time inversely proportional to the bitrate
+    // and limited between 30 - 100 ms
+    const int wait = std::clamp(static_cast<int>(110.0 - mBits), 30, 100);
+
+    m_processWait = std::chrono::milliseconds(wait);
+
+    CLog::Log(LOGDEBUG,
+              "CFileCache::IoControl - setting maxRate to {:.2f} Mbit/s with processWait of {} ms",
+              mBits, wait);
     return 0;
   }
 
diff --git a/xbmc/filesystem/FileCache.h b/xbmc/filesystem/FileCache.h
index 920e747df4..8308ec0dc1 100644
--- a/xbmc/filesystem/FileCache.h
+++ b/xbmc/filesystem/FileCache.h
@@ -15,8 +15,11 @@
 #include "threads/Thread.h"
 
 #include <atomic>
+#include <chrono>
 #include <memory>
 
+using namespace std::chrono_literals;
+
 namespace XFILE
 {
 
@@ -74,6 +77,7 @@ namespace XFILE
     std::atomic<int64_t> m_fileSize;
     unsigned int m_flags;
     CCriticalSection m_sync;
+    std::chrono::milliseconds m_processWait{100ms};
   };
 
 }
-- 
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