Adding convenience functions to get the time to wait for the next frame, while keeping A/V sync

svn-id: r35431

2 files changed, 52 insertions, 0 deletions

diff --git a/graphics/smk_player.cpp b/graphics/smk_player.cpp
index 8252dd9c9b..41e118fc9e 100644
--- a/graphics/smk_player.cpp
+++ b/graphics/smk_player.cpp
@@ -351,6 +351,38 @@ int32 SMKPlayer::getFrameRate() {
 	return _header.frameRate;
 }
 
+int32 SMKPlayer::getFrameDelay() {
+	if (!_fileStream)
+		return 0;
+
+	if (_header.frameRate > 0)
+		return _header.frameRate * 100;
+	if (_header.frameRate < 0)
+		return -_header.frameRate;
+
+	return 10000;
+}
+
+int32 SMKPlayer::getAudioLag() {
+	if (!_fileStream || !_audioStream)
+		return 0;
+
+	int32 frameDelay = getFrameDelay();
+	int32 videoTime = _currentSMKFrame * frameDelay;
+	int32 audioTime = (((int32) _mixer->getSoundElapsedTime(_audioHandle)) * 100);
+
+	return videoTime - audioTime;
+}
+
+uint32 SMKPlayer::getFrameWaitTime() {
+	int32 waitTime = (getFrameDelay() + getAudioLag()) / 100;
+
+	if (waitTime < 0)
+		return 0;
+
+	return waitTime;
+}
+
 bool SMKPlayer::loadFile(const char *fileName) {
 	closeFile();
 
diff --git a/graphics/smk_player.h b/graphics/smk_player.h
index 0e94ab0a39..d7f23b450b 100644
--- a/graphics/smk_player.h
+++ b/graphics/smk_player.h
@@ -83,6 +83,26 @@ public:
 	int32 getFrameRate();
 
 	/**
+	 * Returns the time to wait for each frame in 1/100 ms
+	 * @return the time to wait for each frame in 1/100 ms
+	 */
+	int32 getFrameDelay();
+
+	/**
+	 * Returns the current A/V lag in 1/100 ms
+	 * If > 0, audio lags behind
+	 * If < 0, video lags behind
+	 * @return the current A/V lag in 1/100 ms
+	 */
+	int32 getAudioLag();
+
+	/**
+	 * Returns the time to wait until the next frame in ms, minding any lag
+	 * @return the time to wait until the next frame in ms
+	 */
+	uint32 getFrameWaitTime();
+
+	/**
 	 * Load an SMK encoded video file
 	 * @param filename	the filename to load
 	 */