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[Rockeater]

My house got flooded with a few milimiters of water when a pipe got exploded or something, damage doesn't seem severe but it's just very strange.

[methylatedspirit]

It turns out that if you push audio through a video codec, and you forget to set a pixel format of 24-bit RGB (libx264 generates YUV 4:4:4 if given 24-bit RGB) on the 'video-to-audio' step, you get... interesting results. I'll publish my results later.

Also, Opus, as amazing as it is at being an audio codec, isn't really at all usable as a video codec. Take a look at just 1 frame. Truly the pinnacle of databending.



Just imagine more flashing and general seizure-and-epilepsy-inducing stuff throughout; it's that bad.

[delphonso]

I thought this was a frog meme.

[methylatedspirit]

I'm inclined to respond "Is that a challenge!?", but frankly, if it does that to a black-and-white video, I have no faith that it'll be remotely recognizable with anything even slightly more complex.

[methylatedspirit]

I think I found the problem. It's an issue of alignment. See, most video decodes to 8-bit RGB, in which each R, G and B component gets 8 bits (1 byte) each. When you push this through an audio codec without proper settings, it's not gonna understand that all 3 bytes in there are important. If it sees it as 24-bit PCM (which were my first instincts), you'll end up with

Code: [Select]

┌──────────────────────────────┬────────┬────────┬────────┐
│                              │   R    │   G    │   B    │
│                    Raw video ├────────┼────────┼────────┤
│                              │11110100│11000011│10010001│
├──────────────────────────────┼────────┴────────┴────────┤
│                              │        24bit sample      │
│                              ├──────────────────────────┤
│    Interpreted as 24-bit PCM │                          │
│                              │11110100 11000011 10010001│
│                              │                          │
├──────────────────────────────┼──────────────────────────┤
│                              │                          │
│ What an audio codec might do │11110100 00110000 00000001│
│                              │                          │
└──────────────────────────────┴──────────────────────────┘

So in this example, the color #F4C391 becomes #F43001, which are decidedly different colors. It thinks that the B and G components aren't important, so it just loses precision there, since those are the last 2 bytes in the 24-bit integer anyway. It'd be like rounding off the last 3 digits of a 7-decimal-point number. As for why it produces such "incredible" results, I don't know.

The way you fix this is by telling FFmpeg that its input is unsigned 8-bit PCM. This way, the audio codec is "aware" that each component is actually important, and won't round off color components by accident. This does end up tripling your encoding and decoding times, but at least you won't give people seizures.

I'm not even sure how the 'image-to-audio-to-image' version didn't suffer from this.

[lemon10]

The same graphics card I bought a year and a half ago for 220 bucks (1660) when I built my computer is still competitive enough to be used in some builds.

Now that isn't unusual, it was pretty much the optimal graphics card at that price point so it being used a year and a half later is understandable (hell, buying it 3 or 4 years after it came out used for super cheap would be understandable).

The WTF thing is that it doesn't cost $220 anymore, it now costs nearly $780 bucks. I was aware that the prices on cards and computer stuff went up, but a  nearly 4X increase? Goddamn that's insane.

[hops]

Computer parts price are fucked up right now, possibly due to a combination of pandemic and the US stock market going to shit and investors buying up dumb things. Come back when the bubble burst.

[methylatedspirit]

If you ever need to feel sad, just take a look at the GPU Pricing Index. MSRP is a fantasy.

[martinuzz]

Computer parts price are fucked up right now, possibly due to a combination of pandemic and the US stock market going to shit and investors buying up dumb things. Come back when the bubble burst.

It's mostly chip scarcity (because of supply chains not working in the pandemic)

[hops]

So basically, try not to brick your gaming PC this decade.

[delphonso]

I'm inclined to respond "Is that a challenge!?", but frankly, if it does that to a black-and-white video, I have no faith that it'll be remotely recognizable with anything even slightly more complex.

It wasn't a challenge but now it is after this message. O wamt to see a mess of pixels.

[methylatedspirit]

I'm inclined to respond "Is that a challenge!?", but frankly, if it does that to a black-and-white video, I have no faith that it'll be remotely recognizable with anything even slightly more complex.

It wasn't a challenge but now it is after this message. O wamt to see a mess of pixels.

You mean with a frog meme or with anything "even slightly more complex" (than Bad Apple)? You're gonna have to point me to a frog meme video if it's the former; I'm not getting good search results with "frog meme".

[delphonso]

https://m.youtube.com/watch?v=UN-NgihqbLM

I honestly don't even know what this is.
(The Chinese is just a generic failed call message)

[methylatedspirit]

The bitrate of the "corrupted" video is 160 Mbps. For a 504x360 video. Holy shit. Granted, that's in a lossless format, but holy shit. I'm gonna have to upscale this thing to 4K to get this to be remotely viewable on YouTube.

Edit: The upscaled version has trouble playing in VLC. I have to use ffplay to get it to play at all. Lookin' good!

[methylatedspirit]

Alright. Here you go, delphonso! I'll have to declare a seizure warning.

frog speaking chinese meme """improved"""

It doesn't look like absolute trash upscaled to 4K (nearest neighbor), which is surprising given the insane bitrate of the output video. No wonder it took so long to process. The output was so noisy, that the "compressed" lossless version ended up being larger than the original raw video despite being the same resolution!

As a sidenote: While doing this, Windows decided that my naming scheme for my files was so bad that Explorer literally froze up. Had to rename the problem file in Command Prompt. The name was "frog-meme-vid-libopus-320k.opus". Make of that what you will.