L'Odyssey 4K Ultra HD: decoding an HDR transfer that is sparking debate in the United States

Faced with the avalanche of questions since the publication of the first impressions across the Atlantic, a clarification was necessary. Or at the very least an attempt... For, if our copy of The Odyssey has not yet been put through its paces at AVcesar (the disc is coming...), the feedback from the United States already makes it possible to draw a relatively precise portrait of this edition. Suffice it to say right away, far from being a simple pressing defect, the visual and sound presentation that is currently dividing physical media enthusiasts finds its explanation in Christopher Nolan's uncompromising artistic approach. And no one should be surprised by that...

 

A 4K HDR master with the look of SDR? The figures that are setting alarm bells ringing, or rather their absence, are now known. The disc is formally encoded in [abc]HDR10[/abc], but the first readings point to a meager MaxCLL topping out at 105 nits, coupled with almost no use of the extended color space (0.01% of BT.2020). In practical terms, the signal behaves like standard dynamic range ([abc]SDR[/abc]) encapsulated in an [abc]HDR[/abc] container. Added to this are deliberately lifted blacks, described as milky or grayish. On the audio side, the [abc]DTS-HD[/abc] Master Audio [abc]5.1[/abc] track, lacking object-based mixing, also raises some fears of clipping in the high frequencies, far from the hoped-for earthshaking dynamics.

 

The absolute mimicry of 70 mm Imax film This cold rendering, which turns the Mediterranean Sea into the North Sea according to some disappointed viewers, is nevertheless no mastering error. Indeed, it is known that Christopher Nolan trusts no one when it comes to transferring his films to video. He therefore personally supervises the grading of his works for the home market by comparing the look of 70 mm silver halide film with the digital master intended for Blu-Ray and 4K Ultra HD.

 

The goal is not really to flatter Oled panels with artificial brightness peaks, but to reproduce to the candela exactly the natural and modest brightness of an Imax theatrical projection, which rarely exceeds 80 nits. Boosting [abc]HDR[/abc] would not only have distorted the original photography, but also exacerbated the flicker inherent to the 65-millimeter format. This light pulsing does not come from the shutter, but from the minute natural fluctuations in brightness captured on the negative: on large, uniform, very bright areas, such as the immense daytime skies that fill the 1.78 Imax frame, the film always “breathes” a little. This transfer would therefore prove to be a raw archive of the cinema experience, with no digital artifice.

 

A radical approach that will moreover require viewers to scrupulously disable their television’s dynamic Tone Mapping (DTM) during playback. Faced with a master not exceeding 105 nits and featuring lifted blacks, current display processors will inevitably try to “correct” this flat-looking image, risking completely destroying the fragile balance intended by the director. On the other hand, this master could well be a blessing for projection enthusiasts. With a MaxCLL this low, projectors that are traditionally hard-pressed to display HDR brightness peaks will have almost no Tone Mapping conversion effort to manage. The disc should display organically and smoothly, reproducing almost instantly the aesthetics of a true dark theater.

 

The Odyssey, the radical culmination of Nolan’s method If all this is confirmed, this transfer would fall strictly in line with the filmmaker’s previous Ultra HD releases, while pushing the slider even further. If Oppenheimer (2023) already displayed a very conservative dynamic range (MaxCLL at 186 nits) and Dunkirk (2017) a slightly more generous envelope for sea reflections, The Odyssey would without question offer the darkest and flattest image in his filmography. The real technical break, however, lies in the ratio: gone is the alternation of formats that characterized his previous feature films. The film is here presented entirely in 1.78 (full-screen Imax) over the full 173 minutes. However, some constants remain: the firm rejection of [abc]Dolby Vision HDR[/abc] and the stubborn absence of a [abc]Dolby Atmos[/abc] track in favor of the traditional DTS-HD MA 5.1 stream.

 

All that remains is to put the disc to the test to check whether the [abc]HEVC[/abc] video compression manages to reproduce the thick film grain in dark scenes without generating artifacts. A major challenge for the encoders given the 173 minutes in constant full-screen 1.78, with the absence of black bars allowing no bitrate savings. Bitrate allocation will have to be optimized with surgical precision, even on a triple-layer disc (BD100). Finally, it will be necessary to verify whether the dynamics of the audio mix really avoids any saturation.