2018-02-10 23:37:42 +00:00
2020-01-22 00:59:16 +00:00
<!DOCTYPE html>
2017-09-20 02:35:05 +00:00
2021-04-10 04:00:37 +00:00
< html >
2017-09-20 02:35:05 +00:00
< head >
2020-01-22 00:59:16 +00:00
< meta charset = "utf-8" / >
2021-06-22 00:16:40 +00:00
< meta name = "viewport" content = "width=device-width, initial-scale=1.0" / > < meta name = "generator" content = "Docutils 0.17.1: http://docutils.sourceforge.net/" / >
2017-09-20 02:35:05 +00:00
< title > Media Encoding — Shaka Packager documentation< / title >
2021-06-22 00:16:40 +00:00
< link rel = "stylesheet" type = "text/css" href = "../_static/pygments.css" / >
< link rel = "stylesheet" type = "text/css" href = "../_static/sphinxdoc_new.css" / >
2020-01-22 00:59:16 +00:00
< link rel = "stylesheet" type = "text/css" href = "../_static/graphviz.css" / >
< link rel = "stylesheet" type = "text/css" href = "../_static/table_styling.css" / >
2021-06-22 00:16:40 +00:00
< script data-url_root = "../" id = "documentation_options" src = "../_static/documentation_options.js" > < / script >
2021-04-10 04:00:37 +00:00
< script src = "../_static/jquery.js" > < / script >
< script src = "../_static/underscore.js" > < / script >
< script src = "../_static/doctools.js" > < / script >
2017-09-20 02:35:05 +00:00
< link rel = "index" title = "Index" href = "../genindex.html" / >
< link rel = "search" title = "Search" href = "../search.html" / >
< link rel = "prev" title = "Shaka Packager Library (Continued)" href = "../library_details.html" / >
2020-01-22 00:59:16 +00:00
< / head > < body >
2017-09-20 02:35:05 +00:00
< div class = "related" role = "navigation" aria-label = "related navigation" >
< h3 > Navigation< / h3 >
< ul >
< li class = "right" style = "margin-right: 10px" >
< a href = "../genindex.html" title = "General Index"
accesskey="I">index< / a > < / li >
< li class = "right" >
< a href = "../library_details.html" title = "Shaka Packager Library (Continued)"
accesskey="P">previous< / a > |< / li >
2021-04-10 04:00:37 +00:00
< li class = "nav-item nav-item-0" > < a href = "../index.html" > Shaka Packager documentation< / a > » < / li >
< li class = "nav-item nav-item-this" > < a href = "" > Media Encoding< / a > < / li >
2017-09-20 02:35:05 +00:00
< / ul >
2021-04-10 04:00:37 +00:00
< / div >
2017-09-20 02:35:05 +00:00
< div class = "document" >
< div class = "documentwrapper" >
< div class = "bodywrapper" >
< div class = "body" role = "main" >
2021-06-22 00:16:40 +00:00
< section id = "media-encoding" >
2017-09-20 02:35:05 +00:00
< h1 > Media Encoding< a class = "headerlink" href = "#media-encoding" title = "Permalink to this headline" > ¶< / a > < / h1 >
< p > Shaka Packager does not do transcoding internally. The contents need to be
pre-encoded before passing to Shaka Packager.< / p >
2021-06-22 00:16:40 +00:00
< section id = "general-guidelines-of-how-contents-should-be-encoded" >
2017-09-20 02:35:05 +00:00
< h2 > General guidelines of how contents should be encoded< a class = "headerlink" href = "#general-guidelines-of-how-contents-should-be-encoded" title = "Permalink to this headline" > ¶< / a > < / h2 >
< ul class = "simple" >
2020-01-22 00:59:16 +00:00
< li > < p > Encode multiple bitrates or resolutions of the same content. Shaka Packager
2017-09-20 02:35:05 +00:00
can then package the content into DASH / HLS formats, allowing different
bitrates of the content to be served for different network conditions,
2020-01-22 00:59:16 +00:00
achieving adaptive bitrate streaming.< / p > < / li >
< li > < p > Not a must, but the multibirate content is recommended to have aligned GOPs
2017-09-20 02:35:05 +00:00
across the different bitrate streams. This makes bitrate switching easier and
2020-01-22 00:59:16 +00:00
smoother.< / p > < / li >
< li > < p > We recommend setting GOP size to 5s or less. The streams are usually
2017-09-20 02:35:05 +00:00
switchable only at GOP boundaries. A smaller GOP size results in faster
2020-01-22 00:59:16 +00:00
switching when network condition changes.< / p > < / li >
< li > < p > In the same stream, the bitrate should be more or less the same in the
inter-GOP level.< / p > < / li >
2017-09-20 02:35:05 +00:00
< / ul >
2021-06-22 00:16:40 +00:00
< / section >
< section id = "sample-commands-to-generate-multi-bitrate-content" >
2017-09-20 02:35:05 +00:00
< h2 > Sample commands to generate multi-bitrate content< a class = "headerlink" href = "#sample-commands-to-generate-multi-bitrate-content" title = "Permalink to this headline" > ¶< / a > < / h2 >
< p > Let us say we have a 1080p original content < cite > original.mp4< / cite > containing an audio
track in < cite > AAC< / cite > and a video track in < cite > H264< / cite > . The frame rate is 24. We want to
encode the contents into four resolutions: 360p, 480p, 720p and 1080p with GOP
size 72, i.e. 3 seconds.< / p >
< p > We use < a class = "reference external" href = "https://www.ffmpeg.org/" > ffmpeg< / a > here, which is a common tool used for
transcoding.< / p >
2021-06-22 00:16:40 +00:00
< section id = "h264-encoding" >
2017-09-20 02:35:05 +00:00
< h3 > H264 encoding< a class = "headerlink" href = "#h264-encoding" title = "Permalink to this headline" > ¶< / a > < / h3 >
< ul >
2020-01-22 00:59:16 +00:00
< li > < p > 360p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 -c:a copy \
2017-09-20 02:35:05 +00:00
-vf " scale=-2:360" \
-c:v libx264 -profile:v baseline -level:v 3.0 \
2018-12-20 22:38:40 +00:00
-x264-params scenecut=0:open_gop=0:min-keyint=72:keyint=72 \
2017-09-20 02:35:05 +00:00
-minrate 600k -maxrate 600k -bufsize 600k -b:v 600k \
-y h264_baseline_360p_600.mp4
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 480p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 -c:a copy \
2017-09-20 02:35:05 +00:00
-vf " scale=-2:480" \
-c:v libx264 -profile:v main -level:v 3.1 \
2018-12-20 22:38:40 +00:00
-x264-params scenecut=0:open_gop=0:min-keyint=72:keyint=72 \
2017-09-20 02:35:05 +00:00
-minrate 1000k -maxrate 1000k -bufsize 1000k -b:v 1000k \
-y h264_main_480p_1000.mp4
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 720p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 -c:a copy \
2017-09-20 02:35:05 +00:00
-vf " scale=-2:720" \
-c:v libx264 -profile:v main -level:v 4.0 \
2018-12-20 22:38:40 +00:00
-x264-params scenecut=0:open_gop=0:min-keyint=72:keyint=72 \
2017-09-20 02:35:05 +00:00
-minrate 3000k -maxrate 3000k -bufsize 3000k -b:v 3000k \
-y h264_main_720p_3000.mp4
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 1080p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 -c:a copy \
2017-09-20 02:35:05 +00:00
-vf " scale=-2:1080" \
2018-08-16 00:35:22 +00:00
-c:v libx264 -profile:v high -level:v 4.2 \
2018-12-20 22:38:40 +00:00
-x264-params scenecut=0:open_gop=0:min-keyint=72:keyint=72 \
2017-09-20 02:35:05 +00:00
-minrate 6000k -maxrate 6000k -bufsize 6000k -b:v 6000k \
2018-08-16 00:35:22 +00:00
-y h264_high_1080p_6000.mp4
2017-09-20 02:35:05 +00:00
< / pre > < / div >
< / div >
< / li >
< / ul >
2021-06-22 00:16:40 +00:00
< / section >
< section id = "vp9-encoding" >
2017-09-20 02:35:05 +00:00
< h3 > VP9 encoding< a class = "headerlink" href = "#vp9-encoding" title = "Permalink to this headline" > ¶< / a > < / h3 >
< p > The audio is encoded into < cite > opus< / cite > .< / p >
< ul >
2020-01-22 00:59:16 +00:00
< li > < p > 360p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 \
2017-09-20 02:35:05 +00:00
-strict -2 -c:a opus \
-vf " scale=-2:360" \
-c:v libvpx-vp9 -profile:v 0 \
-keyint_min 72 -g 72 \
-tile-columns 4 -frame-parallel 1 -speed 1 \
-auto-alt-ref 1 -lag-in-frames 25 \
-b:v 300k \
-y vp9_360p_300.webm
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 480p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 \
2017-09-20 02:35:05 +00:00
-strict -2 -c:a opus \
-vf " scale=-2:480" \
-c:v libvpx-vp9 -profile:v 0 \
-keyint_min 72 -g 72 \
-tile-columns 4 -frame-parallel 1 -speed 1 \
-auto-alt-ref 1 -lag-in-frames 25 \
-b:v 500k \
-y vp9_480p_500.webm
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 720p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 \
2017-09-20 02:35:05 +00:00
-strict -2 -c:a opus \
-vf " scale=-2:720" \
-c:v libvpx-vp9 -profile:v 0 \
-keyint_min 72 -g 72 \
-tile-columns 4 -frame-parallel 1 -speed 1 \
-auto-alt-ref 1 -lag-in-frames 25 \
-b:v 1500k \
-y vp9_720p_1500.webm
< / pre > < / div >
< / div >
< / li >
2020-01-22 00:59:16 +00:00
< li > < p > 1080p:< / p >
< div class = "highlight-default notranslate" > < div class = "highlight" > < pre > < span > < / span > $ ffmpeg -i original.mp4 \
2017-09-20 02:35:05 +00:00
-strict -2 -c:a opus \
-vf " scale=-2:1080" \
-c:v libvpx-vp9 -profile:v 0 \
-keyint_min 72 -g 72 \
-tile-columns 4 -frame-parallel 1 -speed 1 \
-auto-alt-ref 1 -lag-in-frames 25 \
-b:v 3000k \
-y vp9_1080p_3000.webm
< / pre > < / div >
< / div >
< / li >
< / ul >
2021-06-22 00:16:40 +00:00
< / section >
< / section >
< / section >
2017-09-20 02:35:05 +00:00
2021-04-10 04:00:37 +00:00
< div class = "clearer" > < / div >
2017-09-20 02:35:05 +00:00
< / div >
< / div >
< / div >
2021-04-10 04:00:37 +00:00
< div class = "sphinxsidebar" role = "navigation" aria-label = "main navigation" >
< div class = "sphinxsidebarwrapper" >
< h3 > < a href = "../index.html" > Table of Contents< / a > < / h3 >
< ul >
< li > < a class = "reference internal" href = "#" > Media Encoding< / a > < ul >
< li > < a class = "reference internal" href = "#general-guidelines-of-how-contents-should-be-encoded" > General guidelines of how contents should be encoded< / a > < / li >
< li > < a class = "reference internal" href = "#sample-commands-to-generate-multi-bitrate-content" > Sample commands to generate multi-bitrate content< / a > < ul >
< li > < a class = "reference internal" href = "#h264-encoding" > H264 encoding< / a > < / li >
< li > < a class = "reference internal" href = "#vp9-encoding" > VP9 encoding< / a > < / li >
< / ul >
< / li >
< / ul >
< / li >
< / ul >
< h4 > Previous topic< / h4 >
< p class = "topless" > < a href = "../library_details.html"
title="previous chapter">Shaka Packager Library (Continued)< / a > < / p >
< div role = "note" aria-label = "source link" >
< h3 > This Page< / h3 >
< ul class = "this-page-menu" >
< li > < a href = "../_sources/tutorials/encoding.rst.txt"
rel="nofollow">Show Source< / a > < / li >
< / ul >
< / div >
< div id = "searchbox" style = "display: none" role = "search" >
< h3 id = "searchlabel" > Quick search< / h3 >
< div class = "searchformwrapper" >
< form class = "search" action = "../search.html" method = "get" >
< input type = "text" name = "q" aria-labelledby = "searchlabel" / >
< input type = "submit" value = "Go" / >
< / form >
< / div >
< / div >
< script > $ ( '#searchbox' ) . show ( 0 ) ; < / script >
< / div >
< / div >
2017-09-20 02:35:05 +00:00
< div class = "clearer" > < / div >
< / div >
< div class = "related" role = "navigation" aria-label = "related navigation" >
< h3 > Navigation< / h3 >
< ul >
< li class = "right" style = "margin-right: 10px" >
< a href = "../genindex.html" title = "General Index"
>index< / a > < / li >
< li class = "right" >
< a href = "../library_details.html" title = "Shaka Packager Library (Continued)"
>previous< / a > |< / li >
2021-04-10 04:00:37 +00:00
< li class = "nav-item nav-item-0" > < a href = "../index.html" > Shaka Packager documentation< / a > » < / li >
< li class = "nav-item nav-item-this" > < a href = "" > Media Encoding< / a > < / li >
2017-09-20 02:35:05 +00:00
< / ul >
< / div >
< div class = "footer" role = "contentinfo" >
© Copyright 2017, Google.
2021-06-22 00:16:40 +00:00
Created using < a href = "https://www.sphinx-doc.org/" > Sphinx< / a > 4.0.2.
2017-09-20 02:35:05 +00:00
< / div >
< / body >
< / html >
