I remember a short film (I don't think it was a series) from my childhood that told a story a group of knights fighting giants. I don't really remember much about the animation, only that it was clearly western and kind of nice looking. It could be older but I saw it in the time frame mentioned. I'll describe the story as I remember it to avoid confusions.
So the story was about these knights who were led by a wizard. The intro exposition told that he had enchanted the knights' shields so that the more honorable the knight was, the brighter it would shine. And the greatest heroes would also receive a golden cross on theirs.
The main character was a young knight who was left on guard duty of the castle whilst the other knights left for a battle. He was reluctant to stay behind since he wanted some shine on his shield, but the others told him that someone needed to stay behind and he was still too young for a battle. So the others left and he stayed. Then suddenly one knight returned and told they needed him on the battlefield and that now he had a chance to earn some honor. He answered that he couldn't go because it was his duty to guard the castle. The knight then got angry and left. It turned out he was actually a giant in disguise.
Then the knights returned and the young knight was still a bit depressed since he hadn't done any fighting. He told about the giant to the other knights and said that he should have come and help them. He said his shield would probably never shine because his cowardice. But the others told him to look at his shield. Not only was it shining as bright as sun, but it also had a golden cross on it.
The movie didn't show much fighting because it was mostly from the point of the young knight. I think it was more of a moral story about sense of duty than trying to tell an actual fantasy tale.