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.

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
[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:


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.

[devashishjaiswal]

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 :^)

[kumarisuman]

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.

[ThePavle]

I never comment on youtube videos, but I had to give props. This is an excellent video. True "Simplify a topic so even a 4 year old can understand." embodiment. Good job!

[audiou]

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

[TobyAsE]

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

[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.

[SilentShiba]

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

[welkin]

Thank so you much for this. Im starting my journey as an audiophile and this was indeed the exact information on audio i needed to begin with. Will visit this every few days. Love from India

[timtreichel]

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.

[networkException]

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

[BenWakefield]

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

[yarom]

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

[jc-aguilar]

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

[mbabb]

Where is the next video? This was wonderful!

[kumarisuman]

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.

[chamodbandara]

best explanation on this topic . thank youu

[Ankit-int]

👍
Best content I've ever discovered on the topic

[niazfaridani-rad]

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

[elton]

Nice video! Please make the second part!