Ticket #10793: 20141111-30-helen-mcf.patch

mythtv/programs/mythcommflag/ClassicCommDetector.cpp

@@ -31 +31 @@
 } FrameAspects;
 
 typedef enum frameFormats {
-    COMM_FORMAT_NORMAL = 0,
-    COMM_FORMAT_LETTERBOX,
-    COMM_FORMAT_PILLARBOX,
-    COMM_FORMAT_MAX
+    COMM_FORMAT_NORMAL    = 0,
+    COMM_FORMAT_LETTERBOX = 1,
+    COMM_FORMAT_PILLARBOX = 2,
+    COMM_FORMAT_MAX       = 4,
 } FrameFormats;
 
 static QString toStringFrameMaskValues(int mask, bool verbose)
@@ -87 +87 @@
     switch (format)
     {
         case COMM_FORMAT_NORMAL:
-            return (verbose) ? "normal" : "N";
+            return (verbose) ? "normal" : " N ";
         case COMM_FORMAT_LETTERBOX:
-            return (verbose) ? "letter" : "L";
+            return (verbose) ? "letter" : " L ";
         case COMM_FORMAT_PILLARBOX:
-            return (verbose) ? "pillar" : "P";
+            return (verbose) ? "pillar" : " P ";
+        case COMM_FORMAT_LETTERBOX | COMM_FORMAT_PILLARBOX:
+            return (verbose) ? "letter,pillar" : "L,P";
         case COMM_FORMAT_MAX:
-            return (verbose) ? " max  " : "M";
+            return (verbose) ? " max  " : " M ";
     }
 
-    return (verbose) ? " null " : "n";
+    return (verbose) ? "unknown" : " U ";
 }
 
 QString FrameInfoEntry::GetHeader(void)
@@ -152 +154 @@
     fps(0.0),                                  framesProcessed(0),
     preRoll(0),                                postRoll(0)
 {
-    commDetectBorder =
-        gCoreContext->GetNumSetting("CommDetectBorder", 20);
     commDetectBlankFrameMaxDiff =
         gCoreContext->GetNumSetting("CommDetectBlankFrameMaxDiff", 25);
     commDetectDarkBrightness =
@@ -189 +189 @@
     postRoll = (long long)(
         max(int64_t(0), int64_t(stopsAt.secsTo(recordingStopsAt))) * fps);
 
+    // CommDetectBorder's default value of 20 predates the change to use
+    // ffmpeg's lowres decoding capability by 5 years.
+    // I believe it should be adjusted based on the height of the lowres video
+    // CommDetectBorder * height / 720 seems to produce reasonable results.
+    // source height =  480 gives border = 20 *  480 / 4 / 720 = 2
+    // source height =  720 gives border = 20 *  720 / 4 / 720 = 5
+    // source height = 1080 gives border = 20 * 1080 / 4 / 720 = 7
+    commDetectBorder =
+        gCoreContext->GetNumSetting("CommDetectBorder", 20) * height / 720;
+
 #ifdef SHOW_DEBUG_WIN
     comm_debug_init(width, height);
 #endif
@@ -316 +326 @@
 
     if (commDetectMethod & COMM_DETECT_LOGO)
     {
+        // Use a different border for logo detection.
+        // If we try to detect logos in letterboxed areas,
+        // chances are we won't detect the logo.
+        // Generally speaking, SD video is likely to be letter boxed
+        // and HD video is not likely to be letter boxed.
+        // To detect logos, try to exclude letterboxed area from SD video
+        // but exclude too much from HD video and you'll miss the logo.
+        // Using the same border for both with no scaling seems to be
+        // a good compromise.
+        int logoDetectBorder =
+            gCoreContext->GetNumSetting("CommDetectLogoBorder", 16);
         logoDetector = new ClassicLogoDetector(this, width, height,
-            commDetectBorder, horizSpacing, vertSpacing);
+            logoDetectBorder, horizSpacing, vertSpacing);
 
         requiredHeadStart += max(
             int64_t(0), int64_t(recordingStartedAt.secsTo(startedAt)));
@@ -897 +918 @@
         delete[] colMax;
         colMax = 0;
 
+        frameInfo[curFrameNumber].format = COMM_FORMAT_NORMAL;
         if ((topDarkRow > commDetectBorder) &&
             (topDarkRow < (height * .20)) &&
             (bottomDarkRow < (height - commDetectBorder)) &&
             (bottomDarkRow > (height * .80)))
         {
-            frameInfo[curFrameNumber].format = COMM_FORMAT_LETTERBOX;
+            frameInfo[curFrameNumber].format |= COMM_FORMAT_LETTERBOX;
         }
-        else if ((leftDarkCol > commDetectBorder) &&
+        if ((leftDarkCol > commDetectBorder) &&
                  (leftDarkCol < (width * .20)) &&
                  (rightDarkCol < (width - commDetectBorder)) &&
                  (rightDarkCol > (width * .80)))
         {
-            frameInfo[curFrameNumber].format = COMM_FORMAT_PILLARBOX;
-        }
-        else
-        {
-            frameInfo[curFrameNumber].format = COMM_FORMAT_NORMAL;
+            frameInfo[curFrameNumber].format |= COMM_FORMAT_PILLARBOX;
         }
 
         avg = totBrightness / blankPixelsChecked;
@@ -1364 +1382 @@
             }
 
             if ((fbp->length > 4) &&
-                (fbp->logoCount > (fbp->frames * 0.60)) &&
+                (!logoInfoAvailable || fbp->logoCount > (fbp->frames * 0.60)) &&
                 (fbp->bfCount < (fbp->frames * 0.10)))
             {
                 if (verboseDebugging)

mythtv/programs/mythcommflag/ClassicLogoDetector.cpp

@@ -100 +100 @@
 
     edgeCounts = new EdgeMaskEntry[width * height];
 
+    // Back in 2005, a threshold of 50 minimum pixelsInMask was established.
+    // I don't know whether that was tested against SD or HD resolutions.
+    // I do know that in 2010, mythcommflag was changed to use ffmpeg's
+    // lowres support, effectively dividing the video area by 16.
+    // But the 50 pixel minimum was not adjusted accordingly.
+    // I believe the minimum threshold should vary with the video's area.
+    // I am using 1280x720 (for 720p) video as the baseline.
+    // This should improve logo detection for SD video.
+    int minPixelsInMask = 50 * (width*height) / (1280*720 / 16);
+
     for (i = 0; edgeDiffs[i] != 0 && !logoInfoAvailable; i++)
     {
         int pixelsInMask = 0;
 
-        LOG(VB_COMMFLAG, LOG_INFO, QString("Trying with edgeDiff == %1")
-                .arg(edgeDiffs[i]));
+        LOG(VB_COMMFLAG, LOG_INFO, QString("Trying with edgeDiff == %1, minPixelsInMask=%2")
+                .arg(edgeDiffs[i]).arg(minPixelsInMask));
 
         memset(edgeCounts, 0, sizeof(EdgeMaskEntry) * width * height);
         memset(edgeMask, 0, sizeof(EdgeMaskEntry) * width * height);
@@ -237 +247 @@
 #endif
         if (((logoMaxX - logoMinX) < (width / 4)) &&
             ((logoMaxY - logoMinY) < (height / 4)) &&
-            (pixelsInMask > 50))
+            (pixelsInMask > minPixelsInMask))
         {
             logoInfoAvailable = true;
             logoEdgeDiff = edgeDiffs[i];
 
             LOG(VB_COMMFLAG, LOG_INFO, 
                 QString("Using Logo area: topleft (%1,%2), "
-                        "bottomright (%3,%4)")
+                        "bottomright (%3,%4), pixelsInMask (%5).")
                     .arg(logoMinX).arg(logoMinY)
-                    .arg(logoMaxX).arg(logoMaxY));
+                    .arg(logoMaxX).arg(logoMaxY)
+                    .arg(pixelsInMask));
         }
         else
         {