# Layered coding > Mediated Wiki article. Canonical URL: https://mediated.wiki/source/Layered_coding > Markdown URL: https://mediated.wiki/source/Layered_coding.md > Source: https://en.wikipedia.org/wiki/Layered_coding > Source revision: 1352336665 > License: Creative Commons Attribution-ShareAlike 4.0 International (https://creativecommons.org/licenses/by-sa/4.0/) {{Short description|Type of data compression for digital video or audio}} '''Layered coding''' is a type of [data compression](/source/data_compression) for [digital video](/source/digital_video) or [digital audio](/source/digital_audio) where the result of compressing the source video data is not just one compressed [data stream](/source/data_stream), as in other types of compression, but multiple streams, called ''layers'', allowing decompression even if some layers are missing. == Overview == With layered coding, multiple data streams or layers are created when compressing the original video stream. This is in contrast to other types of compression, where the result is typically a single data stream. During decompression, all layers can be combined to recreate the original video stream. Additionally, the stream can be decoded even if some layers are missing (though usually a layer hierarchy has to be respected, with a base layer that must be available). If layers are missing, the resulting stream will have reduced visual quality, but will still be usable.{{Cite web|url=http://www.eiti.uottawa.ca/~shervin/pubs/MDC-survey.pdf|title=A Review of Multiple Description Coding Techniques for Error-Resilient Video Delivery|last=|first=|date=|website=|access-date=}} == Use cases == Layered coding is helpful when the same video stream needs to be available in different qualities, for example for [adaptive bitrate streaming](/source/adaptive_bitrate_streaming). Without layered coding, the source video stream must be encoded multiple times to obtain compressed streams with different qualities and bitrates. Layered coding allows only encoding a single time, because streams with different qualities can be obtained by discarding layers. == Related technologies == Layered coding is similar to [multiple description coding](/source/multiple_description_coding) in that both produce multiple compressed streams that can be combined.{{Cite journal|last1=Chakareski|first1=J.|last2=Han|first2=S.|last3=Girod|first3=B.|date=2005-04-01|title=Layered coding vs. multiple descriptions for video streaming over multiple paths|journal=Multimedia Systems|language=en|volume=10|issue=4|pages=275–285|doi=10.1007/s00530-004-0162-3|s2cid=165714|issn=1432-1882}} However, with multiple description coding the different streams are independent of each other, so any subset can be decoded, providing additional flexibility. [Scalable Video Coding](/source/Scalable_Video_Coding) is a video compression standard that makes use of layered coding. == See also == * [MPEG-5 Part 2 / Low Complexity Enhancement Video Coding / LC EVC](/source/LCEVC) - technique of similar approach * [Scalable Video Coding](/source/Scalable_Video_Coding) - [MPEG-4](/source/H.264) specific technique of similar approach * [Bitrate peeling](/source/Bitrate_peeling) * [Hierarchical modulation](/source/Hierarchical_modulation) * [AV1 Scalable video coding](/source/AV1) * [HEVC Scalability Extensions](/source/High_Efficiency_Video_Coding) * {{cite journal |last1=HoangVan |first1=Xiem |last2=NguyenQuang |first2=Sang |last3=Pereira |first3=Fernando |title=Versatile Video Coding Based Quality Scalability With Joint Layer Reference |journal=IEEE Signal Processing Letters |date=2020 |volume=27 |pages=2079–2083 |doi=10.1109/LSP.2020.3039729 |bibcode=2020ISPL...27.2079H |s2cid=228091515 |url=https://eprints.uet.vnu.edu.vn/eprints/id/eprint/4200/1/Final_paper.pdf|archive-url=https://web.archive.org/web/20211214130110/https://eprints.uet.vnu.edu.vn/eprints/id/eprint/4200/1/Final_paper.pdf|url-status=usurped|archive-date=December 14, 2021}} * {{cite book |last1=Lin |first1=Wei-Ting |last2=Liu |first2=Zoe |last3=Mukherjee |first3=Debargha |last4=Han |first4=Jingning |last5=Wilkins |first5=Paul |last6=Xu |first6=Yaowu |last7=Rose |first7=Kenneth |title=2018 Data Compression Conference |chapter=Efficient AV1 Video Coding Using a Multi-layer Framework |date=March 2018 |pages=365–373 |doi=10.1109/DCC.2018.00045 |isbn=978-1-5386-4883-4 |s2cid=50771252 |chapter-url=https://scl.ece.ucsb.edu/sites/default/files/publications/08416609.pdf}} == References == {{Reflist}} Category:Data compression --- Adapted from the Wikipedia article [Layered coding](https://en.wikipedia.org/wiki/Layered_coding) by Wikipedia contributors ([contributor history](https://en.wikipedia.org/wiki/Layered_coding?action=history)). Available under [Creative Commons Attribution-ShareAlike 4.0 International](https://creativecommons.org/licenses/by-sa/4.0/). Changes may have been made.