Audio for Video: A Complete Guide to Sound in Video Products: From PCM and Codecs Loudness, Accessibility, Real-Time Voice Processing: 4

Sound is half the product, and it is the half nobody documents.Viewers forgive a soft picture and leave over bad audio. Yet the video literature treats sound as a footnote, the audio literature is written for studios rather than for products, and the engineer who has to ship a call, a stream or a platform is left assembling the subject from mailing lists. This volume is the first half of that missing book: what digital audio is, how it is compressed, how it travels in streaming, and what has to happen to a voice before it is sent.It starts with the material - sampling, bit depth and dynamic range, channels and layouts, and loudness measured properly in LUFS rather than guessed at. Then codecs: the AAC family, Opus, the Dolby line from AC-3 to AC-4, LC3 and Bluetooth, the speech codecs, and a comparison chapter that chooses on engineering grounds. Then audio in streaming - tracks in HLS, DASH and CMAF, audio ladders and the economics of multiple tracks, the loudness standards and how to actually hit them, multi-language and accessibility, and immersive audio in delivery. It closes with the sender's half of real time: the WebRTC audio chain end to end, echo cancellation, noise suppression, and AGC, VAD and DTX.Every topic reads on its top layer without mathematics and is still accurate; the rigorous layer sits underneath, in boxes you can skip. Each chapter ends with review questions, problems, and a lab you run on FFmpeg, Opus tools, a loudness meter and a browser.What is inside- Digital audio foundations - sampling, bit depth, channels and layouts, loudness in peak, RMS and LUFS, frames and containers- Codecs - AAC, Opus, AC-3/E-AC-3/AC-4, LC3 and Bluetooth, speech codecs, and how to choose- Audio in streaming - audio in HLS, DASH and CMAF, audio ladders and multitrack economics, loudness standards and practice, multi-language and accessibility, immersive audio- Real time, the sender's side - low-latency live audio, the WebRTC audio pipeline, echo cancellation, noise suppression, AGC, VAD and DTXWho it is forVideo and media engineers who own the audio path, WebRTC and conferencing developers, and technical leads choosing codecs and loudness targets. No audio background is assumed; a sound minimum and a video-context appendix carry the prerequisites.25 chapters, 7 appendices, 166 figures, a 349-entry bibliography, an 859-entry glossary and index, and 26 labs. Book 4 of 7, Volume 1, in The Fora Soft Video Engineering Handbook; Volume 2 covers the network side, synchronization, spatial audio and quality.Nikolay Sapunov is CEO and co-founder of Fora Soft, which has built video, real-time and AI systems since 2005: 250+ delivered projects, a 50-engineer team, systems used by NBC, Coca-Cola and Red Bull. This series is the training the company uses on its own engineers.