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What you need to know before touching a video file

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Re: What you need to know before touching a video file

#51

Post by linolevan »

gruez wrote: post #25
MallocVoidstar wrote: post #24

Earlier quoted context omitted.

IIRC VLC used the wrong primaries for converting to RGB for a long time (years) even after it being reported to them as wrong

>even after it being reported to them as wrong Source?

I'm not the OP of the claim (and I love VLC) but maybe they're referring to this early 2018 issue: https://trac.videolan.org/vlc/ticket/19723 which seems to be being actively worked on.

There's also https://code.videolan.org/videolan/vlc/-/issues/25651 but that's an off by one error so likely not really relevant to video playback for the average user.

Re: What you need to know before touching a video file

#52

Post by perching_aix »

jlarocco wrote: post #45
perching_aix wrote: post #44

Earlier quoted context omitted.

Kinda the problem with anecdotes isn't it? :) My own anecdotal experience with VLC was that while every update fixed something, they also broke something in return - and these updates were common. This got annoying enough at some point for me to hop ships, and so I switched to mpc-hc and never looked back. I've since also tried (and keep trying) the to-me still newfangled mpv, but I'm not a fan of the GUI or the keyb…

And you think everybody else should stop using it because you had problems? I'll make up my own mind on it.

Do you think everyone else should start or continue using it because you never had problems?

Let's be kind. Clearly not what either of us were thinking or intended to convey.

Re: What you need to know before touching a video file

#53

Post by zdw »

bcye wrote: post #32
howenterprisey wrote: post #13

Earlier quoted context omitted.

In the anime fan subbing community (which this document is likely from), it's very common to hate on VLC for a variety of imagined (and occasionally real but marginal) issues.

Why is that?

Mostly that VLC has had noticeable issues with displaying some kinds of subtitles made with Advanced SubStation (especially ones taking up much of the frame, or that pan/zoom), which MPV-based players handle better.

If you want a MPV-based player GUI on macOS, https://github.com/iina/iina is quite good.

Re: What you need to know before touching a video file

#54

Post by cruffle_duffle »

pandemic_region wrote: post #18

Could have used this in the nineties, where hunting a specific codec to play that video you downloaded off a BBS was an actual thing.

Oh man it extended well past the 90’s. Finding some weird windows video codec in a dodgy .ru domain was a time honored tradition for quite some time.

I remember all the weird repackaged video codec installers that put mystery goo all over them machine.

The article bashes VLC but I tell you what… VLC plays just about everything you feed it without complaint. Even horribly corrupt files it will attempt to handle. It might not be perfect by any means but it does almost always work.

Re: What you need to know before touching a video file

#55

Post by cnntth »

echelon wrote: post #43
weinzierl wrote: post #41

"Don't use Topaz AI, Anime4k, RealESRGAN, RIFE, etc. Trust me, just don't." Why? I only know Topaz and I always thought it had its narrow but legitimate uses cases for upscaling and equalizing quality?

[flagged]

OP makes zero comments about content generation, and the complaint is about upscaling introducing artifacts not in the original source. No different than hating a bad 4k remaster / sharpening.

Re: What you need to know before touching a video file

#56

Post by dotancohen »

dooglius wrote: post #23
happytoexplain wrote: post #19

I'm always amazed when I see how many people are unfamiliar with VLC hate. It was notorious (to the point of it being a popular meme topic) for video artifacts, slow/buggy seeking, bloated/clumsy UI/menus, having very little format support out of the box, and buggy subtitles. I assume nowadays it's much better, since it seems popular, but its reputation will stick with me forever.

What year was this? I don't know there has ever been a normal format it doesn't support, and I think this has been the case for at least 15 years.

Up until just last month I had never had a problem with VLC. But I don't pirate content so maybe I just hadn't encountered the problematic files. However, recording voice notes in Opus format on my phone, it turns out that VLC has a bug playing Opus files at certain bit rates. However for me this is easily worked around by just using MPV.

Re: What you need to know before touching a video file

#57

Post by weinzierl »

The article talks about image comparisons but does not say what the best way to extract an image is.

If I want the best possible quality image at a precisely specified time, what would I do?

Can I increase quality if I have some leeway regarding the time (to use the closest keyframe)?

Is there a way to "undo" motion blur and get a sharp picture?

Re: What you need to know before touching a video file

#58

Post by dylan604 »

craftkiller wrote: post #46

Something I've never been able to find satisfactory information on (and unfortunately this article also declares it out of scope), is what is the actual hard on-the-wire and on-disk differences between SDR and HDR? Like yes, I know HDR = high dynamic range = bigger difference between light and dark, but what technical changes were needed to accomplish this? The way I understand it, we've got the YCbCr that is being c…

> Naturally, we can stick brighter backlights in our monitors to make the difference between light and dark more significant,

It's actually the opposite that makes the biggest difference with the physical monitor. CRTs always had a residual glow that caused blacks to be grays. It was very hard to get true black on a CRT unless it was off and had been for some time. It wasn't until you could actually have no light from a pixel where black was actually black.

Sony did a demo when they released their OLED monitors where they had the top of each monitor type side by side: CRT, LCD, OLED. The CRT was just gray while the OLED was actually black. To the point that I was thinking in my head that surely this is a joke and the OLED wasn't actually on. That's precisely when the narrator said "and just to show that the monitors are all on" as the video switched to a test pattern.

As for the true question you're getting at, TFA mentions things like color matrix, primaries, and transfer settings in the file. Depending on the values, the decoder makes decision on the math used to calculate the values. You can use any of the values on the same video and arrive at different results. Using the wrong ones will make your video look bad, so ensuring your file has the correct values is important.

From TFA: https://gist.github.com/arch1t3cht/b5b9552633567fa7658deee5a...

Re: What you need to know before touching a video file

#59

Post by ErroneousBosh »

Etheryte wrote: post #17
embedding-shape wrote: post #9

It seems really weirdly written. It's written with a lot of authority, like saying "Don't use VLC" and "Don't use Y" yet provides no reasoning for those things. Just putting "Trust me, just don't" doesn't suddenly mean I trust the author more, it probably has the opposite effect. Some sections seem to differ based on if the reader knows/doesn't know something, but I thought the article was supposed to be for the latt…

Exactly, very hard to take the rest of it seriously after the VLC bit. VLC has literally never left me hanging, across I don't know how many decades. It's gonna take more than a trust me bro to challenge that.

VLC is great for playing stuff back, but can produce some horribly incorrect video files especially if you're dealing with stuff for editing.

There's a reason why VLC isn't used in broadcast stuff and ffmpeg is.

Re: What you need to know before touching a video file

#60

Post by fbias »

swiftcoder wrote: post #42
gruez wrote: post #28

Earlier quoted context omitted.

>Really good quickstart guide It really isn't. You have to scroll 75% of the way through the document before you it tells you what to actually type in. Everything before (9000+ words) is just ranty exposition that might be relevant, but is hardly "quick".

Nah, see, I maintain a commercial video platform, and half the battle is people typing things in before they understand what a codec is. Theory first, practice after.

The discussions in this thread are amusing. It’s a pretty great beginner guide. Almost a parallel to “how to ask questions the smart way” applied to videos.
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