Unify MPEG2 code even more

svn-id: r13365

2 files changed, 80 insertions, 0 deletions

diff --git a/graphics/animation.cpp b/graphics/animation.cpp
index 4808402a46..63bf92f42d 100644
--- a/graphics/animation.cpp
+++ b/graphics/animation.cpp
@@ -151,6 +151,82 @@ bool BaseAnimationState::init(const char *name) {
 #endif
 }
 
+bool BaseAnimationState::decodeFrame() {
+#ifdef USE_MPEG2
+	mpeg2_state_t state;
+	const mpeg2_sequence_t *sequence_i;
+	size_t size = (size_t) -1;
+
+	do {
+		state = mpeg2_parse(decoder);
+		sequence_i = info->sequence;
+
+		switch (state) {
+		case STATE_BUFFER:
+			size = mpgfile->read(buffer, BUFFER_SIZE);
+			mpeg2_buffer(decoder, buffer, buffer + size);
+			break;
+
+		case STATE_SLICE:
+		case STATE_END:
+			if (info->display_fbuf) {
+				/* simple audio video sync code:
+				 * we calculate the actual frame by taking the elapsed audio time and try
+				 * to stay inside +- 1 frame of this calculated frame number by dropping
+				 * frames if we run behind and delaying if we are too fast
+				 */
+
+				/* Avoid deadlock is sound was too far ahead */
+				if (bgSoundStream && !bgSound.isActive())
+					return false;
+
+				if (checkPaletteSwitch() || (bgSoundStream == NULL) ||
+					((_snd->getChannelElapsedTime(bgSound) * 12) / 1000 < framenum + 1) ||
+					frameskipped > 10) {
+					if (frameskipped > 10) {
+						warning("force frame %i redraw", framenum);
+						frameskipped = 0;
+					}
+					drawYUV(sequence_i->width, sequence_i->height, info->display_fbuf->buf);
+
+					if (bgSoundStream) {
+						while ((_snd->getChannelElapsedTime(bgSound) * 12) / 1000 < framenum)
+							_sys->delay_msecs(10);
+					} else {
+						ticks += 83;
+						while (_sys->get_msecs() < ticks)
+							_sys->delay_msecs(10);
+						// FIXME: This used to be used for the Sword2 version of this
+						// method. I do not see any compelling reason why it should be
+						// used, but maybe I am wrong; so if you know more, either
+						// remove this comment, or change the implementation of the 
+						// method to use "sleepUntil" for BS2.
+						//_vm->sleepUntil(ticks);
+					}
+
+				} else {
+					warning("dropped frame %i", framenum);
+					frameskipped++;
+				}
+
+#ifdef BACKEND_8BIT
+				buildLookup(palnum + 1, lutcalcnum);
+#endif
+
+				framenum++;
+				return true;
+
+			}
+			break;
+
+		default:
+			break;
+		}
+	} while (size);
+#endif
+	return false;
+}
+
 bool BaseAnimationState::checkPaletteSwitch() {
 #ifdef BACKEND_8BIT
 	// if we have reached the last image with this palette, switch to new one
diff --git a/graphics/animation.h b/graphics/animation.h
index e532036929..e4a92a66fa 100644
--- a/graphics/animation.h
+++ b/graphics/animation.h
@@ -123,8 +123,12 @@ public:
 	virtual ~BaseAnimationState();
 
 	bool init(const char *name);
+	bool decodeFrame();
+
 protected:
 	bool checkPaletteSwitch();
+	virtual void drawYUV(int width, int height, byte *const *dat) = 0;
+
 #ifdef BACKEND_8BIT
 	void buildLookup(int p, int lines);
 	virtual void setPalette(byte *pal) = 0;