dra7xx: camera: Deinterlacing Buffer Drop Fix

Fix an issue where buffer drops can cause the VPE
to flip the top and bottom fields until the next
drop. Also fix having this as the startup condition.
Repurposed an unused field in GetFrame for this purpose.

Change-Id: Ie8ca716bd99d43b07733a9aadab4439ea9b6ad94
Signed-off-by: David Huang <d-huang@ti.com>

2 files changed, 19 insertions, 7 deletions

diff --git a/camera/V4LCameraAdapter/V4LCameraAdapter.cpp b/camera/V4LCameraAdapter/V4LCameraAdapter.cpp
index 006b8df..b4798f9 100644
--- a/camera/V4LCameraAdapter/V4LCameraAdapter.cpp
+++ b/camera/V4LCameraAdapter/V4LCameraAdapter.cpp
@@ -157,8 +157,8 @@ status_t V4LCameraAdapter::v4lStartStreaming () {
     // for such cameras can be dynamically set frame count that will be
     // skipped  after frame on.
     for (int i = 0; i < mSkipFramesCount; i++) {
-        int id = 0, length = 0;
-        if (GetFrame(id, length) != NULL) {
+        int id = 0, field = 0;
+        if (GetFrame(id, field) != NULL) {
             returnBufferToV4L(id);
         }
     }
@@ -644,6 +644,8 @@ status_t V4LCameraAdapter::startPreview()
         goto EXIT;
     }
 
+    mLastField = V4L2_FIELD_TOP;
+
     startM2MDevice();
 
     for (int i = 0; i < mPreviewBufferCountQueueable; i++) {
@@ -758,7 +760,7 @@ void saveFile(unsigned char* buff, int buff_size) {
     LOG_FUNCTION_NAME_EXIT;
 }
 
-char * V4LCameraAdapter::GetFrame(int &index, int &filledLen)
+char * V4LCameraAdapter::GetFrame(int &index, int &field)
 {
     int ret = NO_ERROR;
     LOG_FUNCTION_NAME;
@@ -799,6 +801,7 @@ char * V4LCameraAdapter::GetFrame(int &index, int &filledLen)
         return NULL;
     }
 
+    field = buf.field;
     mCameraBuffers[index].actual_size = buf.bytesused;
 
     debugShowFPS();
@@ -1038,7 +1041,7 @@ int V4LCameraAdapter::previewThread()
     CameraFrame frame;
     void *y_uv[2];
     int index = 0;
-    int filledLen = 0;
+    int field = 0;
     int stride = 4096;
     char *fp = NULL;
     int in_index =-1, out_index = -1;
@@ -1063,19 +1066,26 @@ int V4LCameraAdapter::previewThread()
     }
 
     {   
-        fp = GetFrame(index, filledLen);
+        fp = GetFrame(index, field);
 
         if(!fp) {
            ret = BAD_VALUE;
            goto EXIT;
         }
-        CAMHAL_LOGEA("CHECK field=%d", ((v4l2_buffer*)(mCameraBuffers[index].opaque))->field);
         CAMHAL_LOGD("GOT IN frame with ID=%d",index);
 
         CameraBuffer *buffer = mPreviewBufs[index];
         int retVal = 0;
         if (mPixelFormat == V4L2_PIX_FMT_YUYV) {
             if (mDeinterlaceEnabled) {
+                if(mLastField == field)
+                {
+                    CAMHAL_LOGEA("CHECK LASTFIELD=field");
+                    returnBufferToV4L(index);
+                    return 0;
+                }
+                mLastField = field;
+                CAMHAL_LOGEA("CHECK NEW FIELD=%d", field);
                 alignedWidth = ALIGN(width, HW_ALIGN);
                 retVal = processFrame(&mCameraBuffers[index], width, height, width, "yuyv",  (void*)(*(buffer_handle_t*)(buffer->opaque)), alignedWidth, height, PAGE_SIZE, "nv12", mDeinterlaceEnabled, 1, index, &in_index, &out_index);
             } else {
diff --git a/camera/inc/V4LCameraAdapter/V4LCameraAdapter.h b/camera/inc/V4LCameraAdapter/V4LCameraAdapter.h
index 538fec2..80629f3 100644
--- a/camera/inc/V4LCameraAdapter/V4LCameraAdapter.h
+++ b/camera/inc/V4LCameraAdapter/V4LCameraAdapter.h
@@ -164,7 +164,7 @@ private:
     //Used for calculation of the average frame rate during preview
     status_t recalculateFPS();
 
-    char * GetFrame(int &index, int &filledLen);
+    char * GetFrame(int &index, int &field);
 
     int previewThread();
 
@@ -233,6 +233,8 @@ private:
     struct VideoInfo *mVideoInfo;
     int mCameraHandle;
 
+    int mLastField;
+
     int nQueued;
     int nDequeued;
     int mQueuedOutputBuffers;