But what is digital audio? (The FLAC Codec #1 - (Digital) Audio and PCM)

Episode 1 of the deep-dive series into FLAC, digital audio and its lossless compression.
Manim source code for the series: github.com/kleinesfilmroellch...
The FLAC specification: www.xiph.org/flac/format.html (Official Specification) datatracker.ietf.org/doc/html... (Internet Draft as of January 2022; mostly a copy of the specification + corrections)
SerenityOS: serenityos.org
95% of this video was created with the Manim animation tool, created by Grant Sanderson (3Blue1Brown) and supported by the Manim community. www.manim.community/
TV news: tagesschau 1960/11/16, 8 pm (www.tagesschau.de/multimedia/... )
Concert recording: Carlos Kleiber - Beethoven symphony No.7, Op.92: mov.4 ( • Video )
Footnotes (square brackets in the video):
[1] For the purposes of this video a codec is just a file format
[2] CD-Audio is not a real file format, but stands for the encoding used by CD audio discs
[3] OVERSIMPLIFICATION, I know, and also I don’t know shit about ZIP so don’t @ me
[4] hyperphysics.phy-astr.gsu.edu/...
[5] We could also average the signal over the short time slice instead, there are multiple approaches of best finding a sample value.
[6] Additionally, there needs to be an analog low pass filter (blocking frequencies above some point) that blocks all frequencies above the maximum representable frequency, the “Nyquist limit”. This needs to be in place both before converting the signal to digital and after re-converting it to analog. Otherwise, you get “aliasing”, pseudo-frequency information that isn’t actually there.
[7] It mainly comes down to the fact that analog low pass filters are imperfect, and these frequencies are well-suited for syncing with other data streams, such as standard definition video in the case of 48kHz. For those reasons, we rather choose the sampling rate a bit too high than too low.
[8] Technically, the entire process of digitizing a signal is called quantization, but that’ll get confusing.
[9] We can also use floating-point numbers (basically decimal), but that’s not something FLAC supports and it’s not generally superior to integer sample representation.
[10] This is a simplification and technically wrong. Any range sizes for these values are possible as an amplitude, and there are five differently sized ranges with six numbers. My point still stands: The differences are very hearable.

[@kleinesfilmroellchen]

Clarifications'n'stuff: This video was animated with 3blue1brown's manim system for mathematical animations in Python. The source code can be found here: github.com/kleinesfilmroellchen/flac-video-resources . (I did put it in the description after publishing, but it seems that it gets overlooked). I received several "well actually" comments that point out that VP9 is lossy. It is, but it's also lossless, it can do both. I did do my research and please only comment about this if you can show me some proof.

[@bronkolie]

AFAIK nearly every video codec is primarily lossy, but is lossless if you use the highest quality setting

[@microcolonel]

No, lossy codecs having a lossless mode is not universal. H.264 I think was the first mainstream video codec that had a lossless capability. Almost no lossy audio codecs have lossless modes, but there are a couple of niche audio codecs that are intended for lossless use that have lossy modes.​@@bronkolie

[@devashishjaiswal6037]

High quality video, great effort. Would love to learn more about flac. I'm glad it's one of SerenityOS developers who's documenting the highly overlooked yet extremely exciting field of multimedia. Internet needs more of these. Keep them coming my friend :^)

[@yarom-os9uf]

Oh my god you are so underrated. THIS VIDEO IS AMAZING

[@thanoskoutr]

I have studied electrical engineering and I am familiar with all these concepts, but I am so excited to see the implementation because I never went beyond the theory of signals and it always seemed that the part that was missing to make it interesting is to see an example or a real use case. Also, great explanation and visuals! Subbed and waiting for the next episode.

[@TobyAsE120]

I'm leaving a comment to make this video more appetizing for the algorithm. Great work, keep going!

[@kumarisuman4565]

I am learning web development because I have to get a job as soon as possible, but my heart goes in understanding low level things and their implementation. I think I am going to enjoy this series.

[@audio2u]

That was beautifully done! Great explanation of basic audio concepts, and fantastic use of visuals to supplement the theory. I'll be watching more.

[@networkException]

Look mom, my SerenityOS screenshot is in a kleines Filmröllchen Video :^)

[@timtreichel3161]

I never heard of FLAC, but I'm familiar with all the other points you talked about and I think you did a really good job of explaining everything and putting everything in one compact, well made video. The only points missing, which I think would help understand everything would be: That microphones and more importantly speakers have membranes, which oscillate/vibrate in order to transmit/receive the signal. The basics of how an ADC/DAC works, because this would couple nicely with the quantisation and sampling.

[@SilentShiba]

I implemented wave decoding for the last week. Thank you for potentially saving me two months my guy

[@BenWakefield]

Excellent video, deserves more views, sharing with all my audio classmates!

[@nishanthshetty435]

Sehr interessant. Danke schön.

[@codechapin]

I have been wanting something like this for a long time, thank you!!!!

[@britters3906]

very poggers explanation

[@kumarisuman4565]

Oh my god! For about a week I was trying to learn about media codec. I was searching for a jpeg Or png codec and mostly about implementation and it's explanation. But it seems like it's the time. I would like more videos on this topic.

[@HickoryDickory86]

For image formats, I would recommend checking out *JPEG XL* and AVIF. They both support lossless and lossy compression methods, but JPEG XL's lossless method produces a smaller file size than even PNG with no loss of image quality or detail.

[@elton9310]

Nice video! Please make the second part!

[@Osax-music]

Excellent explanation, thank you!

[@niazfaridani-rad2147]

Awesome video! When I work on a set, I usually record with 32 bit, so I can save my recording in post. I can then just set the gain without worrying about distortions :D

[@kleinesfilmroellchen]

32-bit int (whole numbers) has the same limits as 16-bit, just a higher dynamic range. 32-bit *float* is used because you can have a gain above 1, so clipping can be prevented. If you're referring to the latter, yes, if you're referring to the former, no. However, FLAC only supports integer bit depths (for compression reasons, see part 2&3) so I just skipped over floating-point sample representation, which is quite different from integer sample representation. The confusion is that a bit depth of 32 bit is ambiguous, it can either mean 32-bit float (very common inside audio applications and as a workflow intermediary, as you point out), or 32-bit int, which is just 16-bit int samples plus some dynamic range. For instance, WAV supports both. Crucially, 32-bit float actually has much lower dynamic range than 32-bit int, especially in louder signals (where it also doesn't matter so, great I guess). You want to look up how floating-point numbers work (IEEE 754 standard) in order to understand why this is the case.

[@mbabb]

Where is the next video? This was wonderful!

[@Ankit-int]

👍 Best content I've ever discovered on the topic

[@venkateshhariharan4341]

great video, thanks mate

[@codingmarco]

Yay, Manim is so cool...

[@mannlevilthe]

Subscribed at the speed of... sound :)

[@beefyjoe2084]

episode 2?

[@nxone9903]

is that a some entry

[@kleinesfilmroellchen]

Look at the date; it doesn't qualify. I would have loved to submit part two to the SoME 2 but didn't have time.

[@xevaly2028]

3Blue1Brown 2.0? Lol pretty hot tho

[@kleinesfilmroellchen]

It's just Manim, a lot of people use that now. I thought it was the most fitting for this kind of video.

[@ymndoseijin]

@@kleinesfilmroellchen you should try sending it over to the manim discord maybe

[@proproxy]

first