InterBEE REVIEW2016

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映画監督樋口 真嗣 氏15First step: converting from SDR to HDRThere were no plans to make “Guard-ian of the Spirit” in HDR at the produc-tion announcement stage. The decision to make it in HDR just before Season 1 was aired was down to the belief of engineering staff such as Mr. Maeda that “we have to do it now”, and the strong desire to make it in HDR when exhibiting it as a sample of 4K drama at MIPCOM in France.“First, a test was conducted. The color and feel was extremely realistic, and we found that color is added to blown-out highlights in SDR. Conversely, we discovered that doing it by the con-ventional method would be difficult as light attenuation was clearly found and differences in brightness and darkness were highly visible. Creating suitable video in SDR was the primary concern. Therefore, we decided to make a HDR version in three steps.” (Mr. Maeda )The plan was as follows: “season 1: convert from 4K/SDR videos without subtitles to 4K/HDR by grading; season 2: filming in both 4K/SDR and 4K/HDR formats; and season 3: filming in 4K/HDR and making a 4K/SDR video for broadcasting purposes.”Mr. Maruyama was in charge of con-verting to HDR for season 1. Because the HDR conversion time was limited to one month due to the seasons 2 and 3 filming schedules, grading was performed in 4K/SDR. Based on that, the highlighted part was extended, color was adjusted, and grading for HDR was performed. However, in the case of processing failures and things that needed treatment, they went back to the S-Log 3 filming data and regraded the HDR images.“We were able to achieve a three-dimensional effect and great array of color. However, because things like metallic luster are really beautiful in HDR you want to show them, but eyes focus on that rather than the actors, the real stars of the piece. So, getting that balance right is important.” (Mr. Maruyama)Aiming for better HDR through accumulated knowledgeFor season 2, a VE for HDR and an HDR monitor were prepared for shoot-ing simultaneously in SDR and HDR. However, this was still unexplored territory, so decisions were made based on impressions of SDR.“There was ample light at the filming location, so the evening scenery and color of the sky were greatly different to impressions of SDR. The VE worked hard to prevent changing the world appearance in HDR and SDR. Con-versely, extremely exciting movie-making can be achieved in HDR.” (Mr. Maeda)He also says that painstakingly portraying the intensity of fine light is also exciting. For example, smoke just becomes a uniform haze in SDR, whereas in HDR, the light and shade of each and every particle is shown. Also, people’s skin and differences in cloth-ing materials are also very clear, so there is a strong sense of presence.Based on these experiences, a trial to create SDR from HDR will be performed for season 3. Mr. Maeda says, “We’ll prob-ably shoot it making use of bright and dark parts, which is a different approach to before. Also, the way to accentuate shade and light as used for SDR may fail when converting from HDR to SDR, so we will probably have to regrade it.”For season 3, we intend to put to use the knowledge accumulated through five months of filming season 2.Mr. Yuta MaruyamaProgram Engineering Division,Engineering Administration DepartmentNHKMr. Kosaku MaedaTechnical Operations & Engineering Center, Technical Planning & Management Division,Broadcast Engineering Department,NHK