windows: improved AVI sound sync (solution for the 32kHz issue)

From d987fc88103f5623b504785b9ee0f53921fa61de Mon Sep 17 00:00:00 2001
From: gocha <gochaism@gmail.com>
Date: Sun, 30 Jan 2011 15:52:07 +0900
Subject: [PATCH] windows: improved AVI sound sync

---
 win32/win32.cpp |   19 +++++++++++++------
 1 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/win32/win32.cpp b/win32/win32.cpp
index 8672d5a..1f1dad1 100644
--- a/win32/win32.cpp
+++ b/win32/win32.cpp
@@ -201,6 +201,7 @@
 #include <io.h>
 //#define DEBUGGER

+#include <math.h>
 #ifndef max
 #define max(a, b) (((a) > (b)) ? (a) : (b))
 #endif
@@ -219,7 +220,8 @@ bool8 do_frame_adjust=false;
 static uint8* avi_buffer = NULL;
 static uint8* avi_sound_buffer = NULL;
 static int avi_sound_bytes_per_sample = 0;
-static int avi_sound_samples_per_update = 0;
+static double avi_sound_samples_per_update = 0;
+static double avi_sound_samples_error = 0;
 static int avi_width = 0;
 static int avi_height = 0;
 static int avi_pitch = 0;
@@ -1415,12 +1417,13 @@ void DoAVIOpen(const TCHAR* filename)
        return;
    }

-   avi_sound_samples_per_update = (wfx.nSamplesPerSec * frameskip) / framerate;
+   avi_sound_samples_per_update = (double) (wfx.nSamplesPerSec * frameskip) / framerate;
    avi_sound_bytes_per_sample = wfx.nBlockAlign;
+   avi_sound_samples_error = 0;

    // init buffers
    avi_buffer = new uint8[avi_image_size];
-   avi_sound_buffer = new uint8[avi_sound_samples_per_update * avi_sound_bytes_per_sample];
+   avi_sound_buffer = new uint8[(int) ceil(avi_sound_samples_per_update) * avi_sound_bytes_per_sample];
 }

 void DoAVIClose(int reason)
@@ -1520,9 +1523,13 @@ void DoAVIVideoFrame(SSurface* source_surface)
    if(pwfex)
    {
        const int stereo_multiplier = (Settings.Stereo) ? 2 : 1;
-
-       S9xMixSamples(avi_sound_buffer, avi_sound_samples_per_update*stereo_multiplier);

-       AVIAddSoundSamples(avi_sound_buffer, avi_sound_samples_per_update, GUI.AVIOut);
+       avi_sound_samples_error += avi_sound_samples_per_update;
+       int samples = (int) avi_sound_samples_error;
+       avi_sound_samples_error -= samples;
+
+       S9xMixSamples(avi_sound_buffer, samples*stereo_multiplier);
+
+       AVIAddSoundSamples(avi_sound_buffer, samples, GUI.AVIOut);
    }
 }
--
1.7.3.1.msysgit.0