[keyframe] Do not fail before the end of the feed when frames are mis…

…sing

When a frame was missing in a VideoFeed, the behaviour used to be to skip
it and try to read the next one. If the next one was missing as well, the
whole process would stop and fail, with the assumption that the feed was
corrupted.

Instead of that, we now keep on skipping the frame and attempting to read
the next one until a valid frame is found or there is no frame left to
read. Dummy scores are still pushed for every frame that is missing.

src/aliceVision/keyframe/KeyframeSelector.cpp

@@ -391,20 +391,21 @@ bool KeyframeSelector::computeScores(const std::size_t rescaledWidthSharpness, c
                     // Read image for sharpness and rescale it if requested
                     currentMatSharpness = readImage(feed, rescaledWidthSharpness);
                 } catch (const std::invalid_argument& ex) {
-                    // currentFrame + 1 = currently evaluated frame with indexing starting at 1, for display reasons
-                    // currentFrame + 2 = next frame to evaluate with indexing starting at 1, for display reasons
-                    ALICEVISION_LOG_WARNING("Invalid or missing frame " << currentFrame + 1
-                                            << ", attempting to read frame " << currentFrame + 2 << ".");
-                    bool success = feed.goToFrame(++currentFrame);
-                    if (success) {
-                        // Will throw an exception if next frame is also invalid
-                        currentMatSharpness = readImage(feed, rescaledWidthSharpness);
-                        // If no exception has been thrown, push dummy scores for the frame that was skipped
+                    bool success = false;
+                    while (!success && currentFrame < nbFrames) {
+                        // currentFrame + 1 = currently evaluated frame with indexing starting at 1, for display reasons
+                        // currentFrame + 2 = next frame to evaluate with indexing starting at 1, for display reasons
+                        ALICEVISION_LOG_WARNING("Invalid or missing frame " << currentFrame + 1
+                                                << ", attempting to read frame " << currentFrame + 2 << ".");
+                        success = feed.goToFrame(++currentFrame);
+                        if (success) {
+                            // Will throw an exception if next frame is also invalid
+                            currentMatSharpness = readImage(feed, rescaledWidthSharpness);
+                        }
+                        // Push dummy scores for the frame that was skipped
                         _sharpnessScores.push_back(-1.f);
                         _flowScores.push_back(-1.f);
-                    } else
-                        ALICEVISION_THROW_ERROR("Could not go to frame " << currentFrame + 1
-                                                << " either. The feed might be corrupted.");
+                    }
                 }
             }