(near) Lossless Digital Video - 5 inch disc

[kfbkfb]

Unlike PCM and Dolby TrueHD, Lossless (UHDTV/Ultra HD Blu-ray or
HDTV/Blu-ray or SDTV/DVD) Digital Video doesn't seem practical on a
5 inch disc for the foreseeable future.

My idea to minimize the Digital Video compression/data reduction artifacts:

Do an (original) frame by (compressed) frame comparison/subtraction
(make sure the difference between the original and compressed
Digital Video is low, perhaps some sort of algorithm that takes into
account the color and detail sensitivity of the human eye when
determining the difference).

This method would tend to minimize poor "encodes" and could even
be quantified in terms of a "maximum difference" number printed on the
disc package.

Kirk Bayne

[FilmFreakosaurus]

The problem is that visually lossless video codecs create very large data files and require very high throughput bandwidth (bitrates) compared to their lossy counterparts like H.265. Sony and Panasonic have created Blu-ray discs with several hundred GB's of storage and would meet these needs, but they are quite expensive per disc and are for pro level archiving. Hollywood is cheap, at least on the consumer side. You do the math.

[eddievanhalen]

I don't think Hollywood is so cheap on the domestic video market. They first gave us Dolby Digital and DTS that were exact copies of the audio tracks played on cinemas. Later they did quite well with Blu ray that still today far surpasses audio and video quality of broadcast T.V. and now we have UHD BD with several flavours of HDR, 10/12 bit video, and lossless object-based audio.
With each new format compression artifacts are less visible. One of the first thing that amazed me when I moved from DVD to BD was not only its superior resolution but also how clean of artifacts picture looked compared to DVD. And now it's the same, it's amazing what HEVC gets with 66/100 Gigs discs. Compression artifacts are there but most of the time for the that's looking for them, if one only pay attention to the movie, artifacts pass undetected.

[mysticwaterfall]

Studios that are too cheap to spring for a 100 gig disc certainly aren't going to spring for anything bigger.

[oddbox83]

Originally Posted by kfbkfb

My idea to minimize the Digital Video compression/data reduction artifacts:

Do an (original) frame by (compressed) frame comparison/subtraction
(make sure the difference between the original and compressed
Digital Video is low, perhaps some sort of algorithm that takes into
account the color and detail sensitivity of the human eye when
determining the difference).

This method would tend to minimize poor "encodes" and could even
be quantified in terms of a "maximum difference" number printed on the
disc package.

Kirk Bayne

These are exactly what a good encode using modern codecs already does.

4:2:0 chroma subsampling works because the human eye doesn't see colour in as much detail so this is a trick to have one full resolution luma channel with lower resolution channels for the chroma information, in basic terms. It can cause visible artefacts especially as I've noticed in deep reds on lower resolution formats like DVD and even on occasion Blu-ray, though the Oppo 203 has impressed me in it's Chroma upsampling technique more than any other player I've owned so makes this less obvious. https://en.wikipedia.org/wiki/Chroma_subsampling

Two or more passes help minimise artefacts by better judging where the bitrate needs to be prioritised and AVC and HEVC are pretty good at hiding artefacts where the human eye tends not to see them. https://en.wikipedia.org/wiki/Variab...-pass_encoding

Blind encodes are not as good as those overseen by a discerning eye, a human eye can further tweak to ensure an encode is going through as invisibly as possible. This is what differentiates, lets say, a bog-standard Shout encode from an Arrow one by David MacKenzie and why raw bitrate alone is not always a reliable judge of quality.

Even studio masters often have to employ compression due to the sheer size of uncompressed 2K and 4K video, though not as much as consumer formats.

[eddievanhalen]

The theatre screenings we all see use lossy compression, less lossy than a 66 or 100 Gig compression we see at home on UHD BD but lossy anyway and keep in mind that theatre screens are much much bigger that the panels or projectors screens we have at home. I think an HEVC well done looks outstanding compression artifacts wise on a home enviroment, 'though I'm curious how one of those good HEVC encodes (let's say a Sony one) would look projected on a big screen cinema.

[FilmFreakosaurus]

Originally Posted by eddievanhalen

The theatre screenings we all see use lossy compression, less lossy than a 66 or 100 Gig compression we see at home on UHD BD but lossy anyway and keep in mind that theatre screens are much much bigger that the panels or projectors screens we have at home. I think an HEVC well done looks outstanding compression artifacts wise on a home enviroment, 'though I'm curious how one of those good HEVC encodes (let's say a Sony one) would look projected on a big screen cinema.

You would start seeing the artifacts, especially in the shadows. You need a more robust codec like a wavelet type (such as Cineform) and a lighter compression ratio. Cineform was actually in the running when UHD Blu-ray was being speced out. Unfortunately, only GOPRO (which bought Cineform) would be getting video codec royalties and the industry hates that, so the MPEG committee stepped in.

A higher average bitrate/lightly filtered HEVC encoding on a 100GB UHD disc would still look good on a larger than normal home theater projection screen, which is still smaller than a decent sized commercial screen. Unfortunately, pretty much Lionsgate is the only studio using BD100's and almost peak rates on a fairly consistant basis.

[eddievanhalen]

Originally Posted by FilmFreakosaurus

You would start seeing the artifacts, especially in the shadows. You need a more robust codec like a wavelet type (such as Cineform) and a lighter compression ratio. Cineform was actually in the running when UHD Blu-ray was being speced out. Unfortunately, only GOPRO (which bought Cineform) would be getting video codec royalties and the industry hates that, so the MPEG committee stepped in.

A higher average bitrate/lightly filtered HEVC encoding on a 100GB UHD disc would still look good on a larger than normal home theater projection screen, which is still smaller than a decent sized commercial screen. Unfortunately, pretty much Lionsgate is the only studio using BD100's and almost peak rates on a fairly consistant basis.

I didn't know there was another codec in consideration for the UHD BD specs. Do you think the codec you're talking about would fare better than HEVC?
One thing I don't understand about Lionsgate is that their BDs suck, plenty of compression artifacts and banding, but they seem to be doing a great job with HEVC using 100 Gigs/3 layer discs and Dolby Vision.
Now that Sony's DACD pressing plant in Terre Haute, Indiana it's stopping CD manufacturing making exclusively Playstation games and UHD BD discs we may see more 100 Gig/3 layer UHD BDs.

[FilmFreakosaurus]

Originally Posted by eddievanhalen

I didn't know there was another codec in consideration for the UHD BD specs. Do you think the codec you're talking about would fare better than HEVC?
One thing I don't understand about Lionsgate is that their BDs suck, plenty of compression artifacts and banding, but they seem to be doing a great job with HEVC using 100 Gigs/3 layer discs and Dolby Vision.
Now that Sony's DACD pressing plant in Terre Haute, Indiana it's stopping CD manufacturing making exclusively Playstation games and UHD BD discs we may see more 100 Gig/3 layer UHD BDs.

If they had chosen one of the higher grade versions of Cineform it would have given HEVC a run for its money.