Digital Audio Explained
This computer science lesson describes how sound is digitally encoded and stored by a computer. It begins with a discussion of the nature of sound in air, namely, a longitudinal wave of compressions and rarefactions. It then explains how sound can be captured by a dynamic microphone, which generates an analogue electrical signal that represents the original analogue sound wave. The digitisation of sound is then described, a process known as analogue to digital conversion. The effect of the sample rate on the quality of a digital sound recording is illustrated, as well as its effect on the size of the sound file. The importance of the bit depth used to digitise a sound wave is also covered, along with the impact of quantisation errors that might result from a low bit depth. This video tutorial mentions some typical sample rates such as speech quality (8KHz) which is used by VIOP applications and telephone voice calls, and CD quality (44.1 KHz) which is used for music recordings. The video concludes with a mention of some different audio file formats including wrappers for uncompressed LPCM data (linear pulse code modulation) such as .WAV and .AIFF, and some compressed audio file formats such as MP3, WMA and M4A.
Chapters:
00:00 The nature of sound
01:22 A microphone to capture sound
01:50 Representing sound with a transverse wave
03:12 Sample rate
07:47 Bit depth
09:51 Summary
Пікірлер: 45
I am an audio professional and educator, and this is hands down one of the best explanations of digital audio I have ever seen!
@ComputerScienceLessons
Жыл бұрын
It's great to hear this from another teacher, and someone who works in the field. Thank you :)KD
U are a legend keep doing this series hope u take it to the next level , and make it coherent, thank you
Very nicely explained for people like myself that have to sometimes work with audio but haven't followed any specialized training for audio engineering! If you're considering taking suggestions for the next videos, for the topic of audio it'd be great to know some basics behind the "codec", the challenges of streaming audio from disk and / or the challenges of ensuring the sound is played when it's needed when working in a multithreaded environment (ie. any modern OS). Keep up the good work!
@ComputerScienceLessons
2 жыл бұрын
Thank you. I am always open to suggestions. I like your ideas and will certainly do more on this. :)KD
@lyntedrockley7295
2 ай бұрын
@@ComputerScienceLessons I've got a suggestion, educate yourself.
Well summarized!
When I convert my audio file in FFMPEG, I see their pcm_S16 le audio codec. And I was amazed at what the bit depth and sample rate were.
Honestly.. You explained so well.. Tomorrow is my exam... And thank you so much for clearing these concepts efficiently .. May God bless you
@ComputerScienceLessons
Жыл бұрын
You are most welcome. All the best of luck. :)KD
@aradhanapandey8229
Жыл бұрын
@@ComputerScienceLessons thanks
great summary. thank you!
@ComputerScienceLessons
Жыл бұрын
You're welcome :)KD
Should be noted that there are limitations of quality of audio file that people can perceive and, from my experience, 16 bit, 44100kHz audio quality is enough to imitate a natural-source sound, the only variable not removed being the quality of speakers. (This conclusion could be drawn from the video, but it's not in the summary, so i'm pointing that out)
@ComputerScienceLessons
2 жыл бұрын
When your ears have taken as much punishment as mine, the best speakers in the world won't make a lot of difference :)KD
Excellent video.
@ComputerScienceLessons
2 жыл бұрын
Thank you :)KD
Thanks, you're a life saver.
@ComputerScienceLessons
5 ай бұрын
You're welcome :)KD
Great video! and a great accent too!
@ComputerScienceLessons
2 жыл бұрын
You're very kind. Thank you :)KD
this is sick ty
@ComputerScienceLessons
Жыл бұрын
ty2 :)KD
It is verrry amazing I'm CS student and it is soooooo much exciting.
@ComputerScienceLessons
2 жыл бұрын
☺☺☺:)KD
Process of recording a sound stored in the form of thousands of individual measurements each at a discrete intervals of time called
Can you explain how DSD works differently from PCM?
@ComputerScienceLessons
2 жыл бұрын
I'll try :)KD
3 month from now this video is supposed to make a million views
@ComputerScienceLessons
2 жыл бұрын
I hope so :)KD
Mega thanks can u upload cat application program that uses Jason AI
@ComputerScienceLessons
2 жыл бұрын
Do you mean the intelligent cat flap?
I may have a little correction for the video. AUDIOFILES argue that compressed digital sound is inferior.
@ComputerScienceLessons
2 ай бұрын
Fair point :)KD
@crazyivan030983
2 ай бұрын
@@ComputerScienceLessons :) greetings from Poland :)
Three advantages of digital music in hindi pls
@ComputerScienceLessons
Жыл бұрын
Here are five (not sure about the translation though): सुवाह्यता। आप एक मोबाइल फोन पर अपने साथ हजारों डिजिटल फाइलें ले जा सकते हैं। कनेक्टिविटी। आप अपना संगीत आसानी से साझा कर सकते हैं। अन्तरक्रियाशीलता। आप प्लेलिस्ट बना सकते हैं और जो आप सुनना चाहते हैं उसे चुन सकते हैं। अभिगम्यता। कोई भी व्यक्ति सही सॉफ्टवेयर से डिजिटल संगीत बना सकता है। आपको आर्केस्ट्रा की जरूरत नहीं है। अनुकूलता। आप नया संगीत आसानी से बना और संसाधित कर सकते हैं। suvaahyata. aap ek mobail phon par apane saath hajaaron dijital phailen le ja sakate hain. kanektivitee. aap apana sangeet aasaanee se saajha kar sakate hain. antarakriyaasheelata. aap plelist bana sakate hain aur jo aap sunana chaahate hain use chun sakate hain. abhigamyata. koee bhee vyakti sahee sophtaveyar se dijital sangeet bana sakata hai. aapako aarkestra kee jaroorat nahin hai. anukoolata. aap naya sangeet aasaanee se bana aur sansaadhit kar sakate hain In English: Portability. You can carry thousands of digital files around with you on a mobile phone. Connectivity. You can share your music easily. Interactivity. You can create playlists and pick and choose what you want to hear. Accessibility. Any individual can make digital music with the right software. You don’t need an orchestra. Adaptability. You can create and process new music easily.
Author, please put proper TITLE for the video, otherwise we don't understand what it is about: example "Explanation of digital sound"
@ComputerScienceLessons
2 жыл бұрын
I've changed it to Digital Audio Explained :)KD
Yes the 1 that use Jason AI
@ComputerScienceLessons
2 жыл бұрын
Ahh! I'm still working on it. It's proving problematic. I seem to get more dead animals than ever. I think my cat just sees it as a challenge. :)KD
As electrical engineer this video really is incomplete, over simplifies, at times is wrong although not overtly (there would be ZERO added fidelity to additional sampling in the example shown at first, and with digital audio the law pass filter used in the recording would block out the frequencies shown in the the second example). If you really want to know what's going on look up Nyquest-Shannon, it's a beautiful thing. And the bit rate only changes the dynamic range of the recording.
@ComputerScienceLessons
Жыл бұрын
I made this video for novices and children, to introduce the fundamental principles. Perhaps one day, I will go into more detail :)KD
@ozriblit
8 ай бұрын
@@ComputerScienceLessons You don't need to do that, its already been done. kzread.info/dash/bejne/h6WdpKybgqi7l7g.htmlsi=OfZL2Vf3eye5lpo0
Too bad you are sticking with the misleading “stairstep” representation of the reconstructed signal. Too often this is used as a -faulty- argument that digital audio is inferior to analog original, whereas properly filtered digital signals will perfectly reproduce the analog original.