Facial coding, along with facial decoding, is a method for assessing emotions and their intensity by observing the facial reactions of individuals exposed to stimuli. Approximately 40 facial muscles can be activated voluntarily or involuntarily to express these emotions. This approach analyzes “muscle contraction points” to evaluate the emotional impact of advertising, as well as to study television content, artistic performances, or to validate events. It is an essential tool in the study of emotions. Facial coding, a precursor to facial decoding, involves identifying emotions from facial expressions. Emotional measurement methods based on facial coding can be applied individually or collectively to evaluate an audience as a whole. At the individual level, this analysis can sometimes be performed simply using a webcam. Some experts question the reliability of emotion recognition devices based on facial analysis. The principle of facial coding relies on observing facial expressions to interpret emotions. A concrete illustration of this method is the overall measurement of emotions during a conference. A concrete example of the application of facial coding is the evaluation of the emotional impact of an advertisement using webcams.