From 24c8e13594e6bfd8fdf835b915c834de8894334d Mon Sep 17 00:00:00 2001
From: s_alexander <s_alexander@b956fd51-792f-4845-bead-9b4dfca2ff2c>
Date: Tue, 8 Dec 2009 02:38:39 +0000
Subject: added starting pts handling

some video files have a starting point for the pts calculation
that starting point has to be subtracted from the pts of each frame
to avoid hanging of the video

git-svn-id: svn://svn.code.sf.net/p/ultrastardx/svn/trunk@2003 b956fd51-792f-4845-bead-9b4dfca2ff2c
---
 src/media/UVideo.pas | 28 ++++++++++++++++------------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/src/media/UVideo.pas b/src/media/UVideo.pas
index 3f25cdf7..6db9cd20 100644
--- a/src/media/UVideo.pas
+++ b/src/media/UVideo.pas
@@ -22,7 +22,7 @@
  * $URL$
  * $Id$
  *}
- 
+
 unit UVideo;
 
 {*
@@ -136,7 +136,7 @@ type
 
     fAspect: real;        //**< width/height ratio
     fAspectCorrection: TAspectCorrection;
-    
+
     fTimeBase: extended;  //**< FFmpeg time base per time unit
     fTime:     extended;  //**< video time position (absolute)
     fLoopTime: extended;  //**< start time of the current loop
@@ -146,7 +146,7 @@ type
     procedure SynchronizeTime(Frame: PAVFrame; var pts: double);
 
     procedure GetVideoRect(var ScreenRect, TexRect: TRectCoords);
-    
+
     procedure ShowDebugInfo();
 
   public
@@ -172,7 +172,7 @@ type
 var
   FFmpegCore: TMediaCore_FFmpeg;
 
-  
+
 // These are called whenever we allocate a frame buffer.
 // We use this to store the global_pts in a frame at the time it is allocated.
 function PtsGetBuffer(CodecCtx: PAVCodecContext; Frame: PAVFrame): integer; cdecl;
@@ -249,7 +249,7 @@ begin
   // TODO: do we really want this by default?
   fLoop := true;
   fLoopTime := 0;
-  
+
   fAspectCorrection := acoCrop;
 end;
 
@@ -481,7 +481,7 @@ end;
  * Decode a new frame from the video stream.
  * The decoded frame is stored in fAVFrame. fTime is updated to the new frame's
  * time.
- * @param pts will be updated to the presentation time of the decoded frame. 
+ * @param pts will be updated to the presentation time of the decoded frame.
  * returns true if a frame could be decoded. False if an error or EOF occured.
  *}
 function TVideoPlayback_FFmpeg.DecodeFrame(): boolean;
@@ -575,6 +575,10 @@ begin
       begin
         pts := 0;
       end;
+
+      if fStream^.start_time <> AV_NOPTS_VALUE then
+        pts := pts - fStream^.start_time;
+
       pts := pts * av_q2d(fStream^.time_base);
 
       // synchronize time on each complete frame
@@ -622,7 +626,7 @@ begin
                  'TimeDiff:  '+inttostr(floor(TimeDifference*1000)));
     {$endif}
 
-    // check if last time is more than one frame in the past 
+    // check if last time is more than one frame in the past
     if (TimeDifference < fTimeBase) then
     begin
       {$ifdef DebugFrames}
@@ -646,7 +650,7 @@ begin
   {$IFDEF VideoBenchmark}
   Log.BenchmarkStart(15);
   {$ENDIF}
-  
+
   // fetch new frame (updates fTime)
   Success := DecodeFrame();
   TimeDifference := NewTime - fTime;
@@ -673,7 +677,7 @@ begin
       Success := DecodeFrame();
   end;
 
-  // check if we got an EOF or error 
+  // check if we got an EOF or error
   if (not Success) then
   begin
     if fLoop then
@@ -699,7 +703,7 @@ begin
           0, fCodecContext^.Height,
           @(fAVFrameRGB.data), @(fAVFrameRGB.linesize));
   {$ELSE}
-  // img_convert from lib/ffmpeg/avcodec.pas is actually deprecated. 
+  // img_convert from lib/ffmpeg/avcodec.pas is actually deprecated.
   // If ./configure does not find SWScale then this gives the error
   // that the identifier img_convert is not known or similar.
   // I think this should be removed, but am not sure whether there should
@@ -709,7 +713,7 @@ begin
             PAVPicture(fAVFrame), fCodecContext^.pix_fmt,
             fCodecContext^.width, fCodecContext^.height);
   {$ENDIF}
-  
+
   if (errnum < 0) then
   begin
     Log.LogError('Image conversion failed', 'TVideoPlayback_ffmpeg.GetFrame');
@@ -940,7 +944,7 @@ begin
 
   fTime := Time;
   fEOF := false;
-  fFrameTexValid := false; 
+  fFrameTexValid := false;
 
   if (av_seek_frame(fFormatContext, fStreamIndex, Floor(Time/fTimeBase), SeekFlags) < 0) then
   begin
-- 
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