Mpeg: Look for an AU before decoding a frame.

Otherwise FFmpeg will read in partial data and create a corrupt frame.

This happens in Valkyrie Profile in the intro, causing distortion.
Additionally, waiting causes the ending video to play correctly.

Note that some short videos (like door opening in Valkyrie Profile) may
not have an AU separator.

Core/HW/BufferQueue.h

@@ -124,6 +124,22 @@ struct BufferQueue {
 		return bytesgot;
 	}
 
+	bool containsAuAfter(int off) {
+		int avail = getQueueSize();
+		for (int i = off; i <= avail - 3; ++i) {
+			if (peek(i) != 0) {
+				continue;
+			}
+
+			if (peek(i + 1) == 1 && peek(i + 2) == 9) {
+				NOTICE_LOG(HLE, "found AU at offset %d: %d", i, i > 0 ? peek(i - 1) : 1337);
+				return true;
+			}
+		}
+
+		return false;
+	}
+
 	void DoState(PointerWrap &p) {
 		auto s = p.Section("BufferQueue", 0, 1);
 
@@ -172,6 +188,11 @@ struct BufferQueue {
 		return pts;
 	}
 
+	unsigned char peek(int i) {
+		int off = start + i % bufQueueSize;
+		return bufQueue[i];
+	}
+
 	unsigned char* bufQueue;
 	int start, end;
 	int bufQueueSize;

Core/HW/MediaEngine.cpp

@@ -553,11 +553,40 @@ void MediaEngine::updateSwsFormat(int videoPixelMode) {
 #endif
 }
 
+void MediaEngine::HandleDecodedFrame(AVCodecContext *ctx, int videoPixelMode, bool skipFrame) {
+	if (!m_pFrameRGB) {
+		setVideoDim();
+	}
+
+	if (m_pFrameRGB && !skipFrame) {
+		updateSwsFormat(videoPixelMode);
+		// TODO: Technically we could set this to frameWidth instead of m_desWidth for better perf.
+		// Update the linesize for the new format too.  We started with the largest size, so it should fit.
+		m_pFrameRGB->linesize[0] = getPixelFormatBytes(videoPixelMode) * m_desWidth;
+
+		sws_scale(m_sws_ctx, m_pFrame->data, m_pFrame->linesize, 0,
+			ctx->height, m_pFrameRGB->data, m_pFrameRGB->linesize);
+	}
+
+	if (av_frame_get_best_effort_timestamp(m_pFrame) != AV_NOPTS_VALUE)
+		m_videopts = av_frame_get_best_effort_timestamp(m_pFrame) + av_frame_get_pkt_duration(m_pFrame) - m_firstTimeStamp;
+	else
+		m_videopts += av_frame_get_pkt_duration(m_pFrame);
+}
+
 bool MediaEngine::stepVideo(int videoPixelMode, bool skipFrame) {
 #ifdef USE_FFMPEG
 	auto codecIter = m_pCodecCtxs.find(m_videoStream);
 	AVCodecContext *m_pCodecCtx = codecIter == m_pCodecCtxs.end() ? 0 : codecIter->second;
 
+	if (m_desWidth == 0 || m_desHeight == 0) {
+		// Sometimes there is no separator, let's assume 20kb is always enough.
+		// Less than 20kb is not enough for Valkyrie Profile.
+		if (!m_pdata->containsAuAfter(m_mpegheaderSize) && m_pdata->getQueueSize() < 20480) {
+			return false;
+		}
+	}
+
 	if (!m_pFormatCtx)
 		return false;
 	if (!m_pCodecCtx)
@@ -580,23 +609,7 @@ bool MediaEngine::stepVideo(int videoPixelMode, bool skipFrame) {
 
 			int result = avcodec_decode_video2(m_pCodecCtx, m_pFrame, &frameFinished, &packet);
 			if (frameFinished) {
-				if (!m_pFrameRGB) {
-					setVideoDim();
-				}
-				if (m_pFrameRGB && !skipFrame) {
-					updateSwsFormat(videoPixelMode);
-					// TODO: Technically we could set this to frameWidth instead of m_desWidth for better perf.
-					// Update the linesize for the new format too.  We started with the largest size, so it should fit.
-					m_pFrameRGB->linesize[0] = getPixelFormatBytes(videoPixelMode) * m_desWidth;
-
-					sws_scale(m_sws_ctx, m_pFrame->data, m_pFrame->linesize, 0,
-						m_pCodecCtx->height, m_pFrameRGB->data, m_pFrameRGB->linesize);
-				}
-
-				if (av_frame_get_best_effort_timestamp(m_pFrame) != AV_NOPTS_VALUE)
-					m_videopts = av_frame_get_best_effort_timestamp(m_pFrame) + av_frame_get_pkt_duration(m_pFrame) - m_firstTimeStamp;
-				else
-					m_videopts += av_frame_get_pkt_duration(m_pFrame);
+				HandleDecodedFrame(m_pCodecCtx, videoPixelMode, skipFrame);
 				bGetFrame = true;
 			}
 			if (result <= 0 && dataEnd) {

Core/HW/MediaEngine.h

@@ -98,6 +98,10 @@ class MediaEngine
 	void updateSwsFormat(int videoPixelMode);
 	int getNextAudioFrame(u8 **buf, int *headerCode1, int *headerCode2);
 
+#ifdef USE_FFMPEG
+	void HandleDecodedFrame(AVCodecContext *ctx, int videoPixelMode, bool skipFrame);
+#endif
+
 public:  // TODO: Very little of this below should be public.
 
 	// Video ffmpeg context - not used for audio