We are delighted to welcome you to Nice, France, for ACM Multimedia 2019, the 27th ACM International Conference on Multimedia. ACM Multimedia is the premier international conference in the area of multimedia within the field of computer science. Since 1993, ACM Multimedia has been bringing together researchers and practitioners from academia and industry to present innovative research and discuss recent advancements. This year's conference delivers the cutting-edge research results, covering the latest findings in the field, for which the ACM Multimedia conference series is already widely known. In addition, we are offering some key innovations, which we would like to highlight in this welcome message. We are proud to introduce, for the first time at ACM Multimedia, a Reproducibility Track, whose goal is to incentivize and support researchers in sharing resources that will help others to reproduce their work. The track is dedicated to publishing papers that document the reproducibility of work that has previously appeared at ACM Multimedia, and implements the ACM Artifact Review and Badging system. Also, for the first time, the conference features a Sisters and Ambassadors session. This session provides a window on what is happening at other conferences of the SIGMM, as well as related conferences in other fields. It is a special pleasure to host an innovative networking event at the conference, called "Meet the Chairs". The event will bring together newcomers with established members of the community in a "ConfLab", which is a natural interaction activity, which simultaneously serves two goals: allowing people to get to know each other and also creating a multimodal data set. The data set will be made available to the community to study multimodal research questions related to human behavior and communication. ConfLab serves as a model for best practices in ethical sourcing of data for multimedia research. You will quickly notice that this year posters are a centerpiece of the conference. Reading posters and interacting with authors during poster sessions are a highly effective channel of communication of research results and discussion of findings. All conference papers will be presented as posters, which are hanging throughout the conference. We hope that you take advantage of the poster sessions, but also other breaks, to study the posters and to interact directly with the paper authors. During the oral sessions, selected papers will be presented as 10 minute presentations, followed by a question and answer period. Make good use of this opportunity to ask the authors about their work. Other papers will be presented as two minute "flash" presentations. These presentations will direct the audience to specific posters for further interaction with the authors. There is no status distinction between these presentation modes. Selection of presentation format for accepted papers is based on breadth of interest and topical balance of the program. Continuing ACM Multimedia's commitment to building diversity, this year's conference will feature a special conference-wide diversity event. Maria Menendez-Blanco and Pernille Bjørn of the Department of Computer Science, University of Copenhagen, Denmark, will make a presentation on their experiences in broadening the participation of women in computer science research. They will also offer an interactive installation, which supports discussions about inclusion in computer science, and actively contributes to building new perspectives beyond the narratives that currently dominate in our field.