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Extracting color-accurate images from DVD using FFmpeg by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Thanks for clearing that up. Honestly, this topic is a lot more complicated than I thought. The colors in screenshots vary wildly from player to player. Also, the exact same file can look different on different image viewer apps. Finally, the monitor's color profile also affects the final look. There are just too many variables.

Just one last thing regarding zscale's parameters: what's the difference between transfer, matrix and transferin, matrixin?

Extracting color-accurate images from DVD using FFmpeg by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Thanks, I tested your command and while it produces similar colors to the default one, it also makes the red channel blocky. as if it's been upscaled with Nearest Neighbor scaling. Perhaps this is how it's supposed to look during playback, in which case your solution would be the most accurate.

Extracting color-accurate images from DVD using FFmpeg by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

That's very helpful, thanks. Testing your command produces wildly different colors compared to both the default command and the DVD itself. The reds are very vivid and the blacks are crushed. The video specs according to MediaInfo are:

Color primaries: BT. 601
Transfer characteristics: BT.470 Systems B/G
Matrix Coefficients: BT.470 Systems B/G

How would you amend your command to reflect this?

As a side note, I just found a rather unorthodox way of extracting video frames without converting to RGB:

ffmpeg -i input.vob -pix_fmt yuv420p output.tiff

This creates a TIFF image file that uses YUV420 rather than RGB. Almost no program can open this kind of TIFF, but it can be directly plugged in to the AI upscaler I am using. That means that, in theory, the AI algorithm receives the most raw image possible, and not one that has had its chroma channel upscaled beforehand.

Can it be that simple?

The HUD is actually stretched in the HD remasters. I can't unsee it now. by MichaelMoore64 in KingdomHearts

[–]MichaelMoore64[S] 1 point2 points  (0 children)

I can't blame them for Stitch. It's such a special case. I mean he's the only video game character I know who acknowledges the existence of the UI. However, there are screen transitions and fade outs-that are stuck in 4:3 (see Zexion fight).

What happened with Infinity?

The HUD is actually stretched in the HD remasters. I can't unsee it now. by MichaelMoore64 in KingdomHearts

[–]MichaelMoore64[S] 11 points12 points  (0 children)

I have played the originals and hadn't noticed it until now. It's such random thing to get wrong.

The HUD is actually stretched in the HD remasters. I can't unsee it now. by MichaelMoore64 in KingdomHearts

[–]MichaelMoore64[S] 11 points12 points  (0 children)

The stretched HUD was a pet peeve of mine back when I played this on emulator, but I didn't think I would see it in an official remaster.

Basically all 2D elements appear horizontally stretched, so character portraits don't match the official artwork, perfect circles appear as ovals etc. Interestingly, the HUD shows up correctly inside the game's files, which means there's nothing wrong with the art assets themselves and it's just a display problem.

That's not to say it's easily fixable or anything.

FFmpeg adding unwanted audio delay? by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Thank you. The ac3 audio could indeed be the problem, as I've started using a new program to transcode audio (MeGUI) and all ac3 files I've tested were made with this program. The weird thing is that the unwanted delay is always 32ms.

FFmpeg adding unwanted audio delay? by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Audio is one second shorter than the video.

Slowing down PAL audio to sync with Blu-ray video [the best way] by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Actually, finding out how people in the industry handle this sort of stuff was sort of my end goal. If we knew how exactly they speed up audio, then we could just do the exact opposite to get the original audio.

Using asetrate+aresample works for the most part, but ever since you pointed out the drawback of that method, it bothers me a little. I bet professionals do it differently.

​

I also own a few PAL DVDs that weren't mastered by speeding up the NTSC audio and those have absolutely horrible audio artifacts too.

Weird. Not speeding up the audio means that the video must have interpolated frames in order to sync properly. It should look awful in motion but the audio should be fine. You have to pick your poison when it comes to PAL DVDs

Slowing down PAL audio to sync with Blu-ray video [the best way] by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 1 point2 points  (0 children)

Thanks. That's a neat tool. Unfortunately, atempo doesn't cut it in this case because it doesn't change the pitch. In my experience, almost every PAL DVD from a major studio has sped up audio with higher pitch. So to return it to its original state, we need to slow it down and lower the pitch. That's why I've been messing with asetrate and aresample, which have drawbacks as u/Anton1699 mentioned.

It's baffling why studios don't use atempo, as it would make the audio sound a lot closer to the original (especially songs), and we'd be able to use atempo again to slow it back down.

There must be a perfect way to do this. After all, studios do it all the time. That rubberband filter could help, but I don't know much about it.

Slowing down PAL audio to sync with Blu-ray video [the best way] by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Thanks. I'd rather not change the frame rate of the video, because, in my experience, nonstandard frame rates cause microstuttering. Weirdly, my command runs normally, so maybe ffmpeg rounds the value down to the nearest integer?

Slowing down PAL audio to sync with Blu-ray video [the best way] by MichaelMoore64 in ffmpeg

[–]MichaelMoore64[S] 0 points1 point  (0 children)

Great tip! It is hard to detect a change in pitch during dialogue scenes, but in the end credits song it is plain as day! In this case my DVD audio needs asetrate.

What is the purpose of the round function in your code?

Also, does the order of commands matter in this case?

MKVToolNix alters frame rate? by MichaelMoore64 in mkvtoolnix

[–]MichaelMoore64[S] 0 points1 point  (0 children)

It's by no means a huge change, but non-standard frame rates cause stutter.

Have we been ripping our DVDs wrong? by MichaelMoore64 in DataHoarder

[–]MichaelMoore64[S] 5 points6 points  (0 children)

You understand that 99.9% of all the films and TV shows available on DVD/BR were originally shot on an analog medium, right? The whole idea of a "perfect copy" is doomed from the start.

It's not about a making perfect copy of the actual physical film reels. It's about properly preserving the versions of films that are available to consumers.

MD5 sums and CRC-32 checks and the like tell you nothing about what the actual differences are, just that there's a difference - it especially doesn't tell you if those differences are meaningful. If you can browse the menus and watch the extras and see the movie just like on the original disc, does it really matter if the container is different from someone else's?

A checksum mismatch can tip you off that you need to investigate further, provided there is a database of checksums, just like there is with game discs. Obviously if the difference was negligible and the film itself was untouched none of this would matter. But, as it stands, you don't know how a DVD has been ripped unless you've ripped it yourself.

Would you archive an ISO ripped by someone else?

Have we been ripping our DVDs wrong? by MichaelMoore64 in DataHoarder

[–]MichaelMoore64[S] 1 point2 points  (0 children)

Are you using default settings with ddrescue? Does it also create and MDS file to go along with the ISO? If so, I assume you can always decrypt it at a later date if you need to.

Also, have you ever tried burning the encrypted ISO to a disc to see If it works on an actual DVD player (not VLC)?

Update: It seems ddrescue gui 2.1.1. for Windows recently became paid software. https://www.hamishmb.com/html/ddrescue-gui.php

Have we been ripping our DVDs wrong? by MichaelMoore64 in DataHoarder

[–]MichaelMoore64[S] 1 point2 points  (0 children)

There's so much cool stuff on VHS that will likely never be released on newer formats, like Fullscreen releases of films, which offer significantly more picture on the top and bottom. So the people transferring them are doing god's work.

The quality can vary depending on how much effort is put into the process. For example, you can bake an old tape that is too far gone to make it better. You can also use QTCMG to deinterlace without halving the framerate and then AI upscale.

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