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The Blackcoat's Daughter Review

(posted in blog)

The first film I decided to tackle in my new quest to digitize my entire Blu-ray and DVD collection was the 2015 slow-burn demonic possession film The Blackcoat’s Daughter. I chose this somewhat arbitrarily–mainly because I haven’t seen it since around when it came out and I remember really liking it but not much else. And oh boy, let me tell you, I am glad I did.

The Blackcoat’s Daughter is a dark film, both figuratively and literally. It’s filmed almost entirely in zero-to-low-light conditions which, if you’ve ever spent any time trying to learn about filmography or photography, are the conditions under which it’s most difficult to retain detail and clarity. This goes quadruply-so when you’re trying to compress video from its Blu-ray source to a reasonable file size without turning the visuals into a horrible pukey mess in the process.

My first attempt at converting my Blu-ray rip into a watchable H.265 video was a fairly naive one. I read that, for 1080p content, the ideal quality setting in Handbrake is between 20-24. Fine, I thought; I want to retain as much quality as possible so I’ll do even better and crank it to 18 (when discussing constant-quality settings, lower numbers equate to higher bitrates and quality). The result was disappointing.

frame with banding

If you didn’t know what “banding” was before, it’s referring to those ugly, distracting lines that appear in an area that should be a smooth gradient. Compare the above frame to the same shot from the original source. The highlighted section has had the black levels and contrast adjusted to exaggerate the effect and make it as noticable as it is on my 65-inch plasma TV in the dark. You’ll notice the below shot has a much smoother looking gradient than above. (These images have been further compressed to JPEG format, so they’re not 100% accurately representative of the problem, but you get the idea.)

frame without banding

I’m sure there are people out there who could watch a film with banding artifacts and not be bothered (and on a smaller or cheaper TV or display you probably won’t even see it), but I’m definitely not one of those people. Once I notice it, it’s all I see about the film. I can’t peel my eyes away from those hideous, sometimes dancing striations in the frame. And The Blackcoat’s Daughter is absolutely littered with scenes similar to the above–huge empty expanses of dimly-lit wall gradients in scene after scene after scene. Completely unwatchable with banding problems.

My initial search for a solution suggested that I encode the film using 10-bit color instead of 8-bit. Even though the source material itself is only 8-bit, the idea is that the final encoded output will have cleaner gradients and less banding if it has the larger 10-bit color palette to choose from. In my testing with this film, it made no appreciable difference. The banding was just as noticeable and distracting and horrible.

While I was testing, I discovered that this film is currently available on Netflix, so I loaded it up and watched the same scenes on there, almost certain that I would see banding artifacts that were at least as bad if not worse than what I was producing with higher-than-recommended quality settings. To my surprise, Netflix’s version of the film had no banding at all in the above scene.

Now armed with the knowledge that it was possible to encode this film at Netflix-level bitrates without banding, I had to discover what the secret was. Even if it meant abandoning H.265 and encoding to the less efficient H.264 codec that I’m pretty sure Netflix was streaming to me, I absolutely had to get my local copy to at least the same level of quality as Netflix. Otherwise what’s the damn point?

After many more hours of trawling documentation and forum posts, and watching and re-watching the first 3 minutes of The Blackcoat’s Daughter at least two dozen times with different encoder settings, I finally discovered the solution. The thing that tipped me off was from the x265 documentation:

–aq-mode <0|1|2|3|4>

3 - AQ enabled with auto-variance and bias to dark scenes. This is recommended for 8-bit encodes or low-bitrate 10-bit encodes, to prevent color banding/blocking.

To make a long story short, it turned out that setting aq-mode=3 on its own does not solve the banding issue. There is a related setting called aq-strength that makes all the difference, however. Leaving the default aq-mode=1 (because bumping it to 3 seems to quadruple the bitrate without actually affecting quality), and bumping aq-strength to 1.5 almost completely removed all banding problems I was seeing while only very marginally increasing bitrate.

In the end, the Handbrake settings I have settled on (for this and presumably all of my upcoming encodes) are using the Official > Matroska > H.265 MKV 1080p30 preset, changing to the 10-bit x265 encoder, bumping the quality up to 20 and the speed preset down to medium, and using the extra settings aq-mode=1:aq-strength=1.5. I watched the entire movie through on these settings, and only noticed banding in a small number of exceptionally dimly lit scenes. When I watched those same scenes on Netflix the banding was much, much worse. That, combined with (to my eyes) no loss of detail from the original Blu-ray satisfies me that I’ve found a configuration that gives me better-than-streaming quality with acceptable file sizes. This film, for example, went from a 19GB source down to 2.4GB compressed.

I believe that by, through pure luck-of-the-draw, focusing so heavily on optimizing my settings for this movie, I can now be confident about the quality of darker scenes across the rest of my movie collection. This is as good as it’s going to get at the quality and file sizes that I’m aiming for.

Anyway, now that I’ve rambled on about the minutia of H.265 video encoding, it’s time to talk about the actual movie. In my opinion it is really good, but only if you can appreciate slow, character-oriented atmospheric horror without much action. Calling The Blackcoat’s Daughter a slow-burn is a massive underrepresentation of its zen-like pacing. In the final act of the movie there is a twist which, without spoilers, felt to me a lot like cheating when it was finally revealed, but I enjoyed the movie so much that I can give it a pass.

The introduction of the first two main characters during the first act, the introduction of the third main character during the second act, and the weaving together of all three stories through the climax and conclusion are handled expertly. Despite its pacing there wasn’t a single scene that I felt didn’t earn its place, nor were there any moments during which I found myself bored or wishing things would progress quicker.

The Blu-ray includes a writer/director’s audio commentary track in which Oz Perkins gives some insight into thought processes and some behind-the-scenes information about the movie that was quite delightful to listen to during a second play-through of the movie.

It’s really great, but not in an accessible way where I would expect my mother in-law to enjoy it. Your mileage may vary.

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