{"id":8373,"date":"2013-12-04T16:01:54","date_gmt":"2013-12-04T16:01:54","guid":{"rendered":"http:\/\/zerokidz.com\/ideas\/?p=8373"},"modified":"2014-06-15T02:50:58","modified_gmt":"2014-06-15T06:50:58","slug":"notes-on-rtl-sdr-source-code-first-impressions","status":"publish","type":"post","link":"https:\/\/reactivemusic.net\/?p=8373","title":{"rendered":"Notes on rtl-sdr source code &#8211; first impressions"},"content":{"rendered":"<p>I did a quick read of source code (rtl-fm.c) today.<\/p>\n<p>Basically it opens an input stream of IQ samples from the rtl-sdr device, demodulates filters, and outputs audio.<\/p>\n<p>Other than usual madness with threads and locking &#8211; the code is fairly straightforward. Not well commented &#8211; but clear enough that we could extract the input streaming and frequency (device) control to make a Max external. One question would be whether or not to do the downsampling in the external, or in Max?<\/p>\n<p>Rough estimate would be this project would involve about 1-2 weeks of analysis and hacking. Possibly less &#8211; but there is a learning curve &#8211; and a heuristic stuff which is required to work with the hardware.<\/p>\n<p>Fortunately it actually works in MacOS and Windows &#8211; and there are plenty of other examples to compare it to. But this is not a casual evening project.<\/p>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>I did a quick read of source code (rtl-fm.c) today. Basically it opens an input stream of IQ samples from the rtl-sdr device, demodulates filters, and outputs audio. Other than usual madness with threads and locking &#8211; the code is fairly straightforward. Not well commented &#8211; but clear enough that we could extract the input &hellip; <\/p>\n<p class=\"link-more\"><a href=\"https:\/\/reactivemusic.net\/?p=8373\" class=\"more-link\">Continue reading<span class=\"screen-reader-text\"> &#8220;Notes on rtl-sdr source code &#8211; first impressions&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","footnotes":""},"categories":[230,21],"tags":[190,57,83,243],"class_list":["post-8373","post","type-post","status-publish","format-standard","hentry","category-development","category-dsp","tag-portfolio","tag-radio","tag-sdr","tag-software-defined-radio"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.7 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>Notes on rtl-sdr source code - first impressions - reactive music<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/reactivemusic.net\/?p=8373\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"Notes on rtl-sdr source code - first impressions - reactive music\" \/>\n<meta property=\"og:description\" content=\"I did a quick read of source code (rtl-fm.c) today. Basically it opens an input stream of IQ samples from the rtl-sdr device, demodulates filters, and outputs audio. Other than usual madness with threads and locking &#8211; the code is fairly straightforward. Not well commented &#8211; but clear enough that we could extract the input &hellip; Continue reading &quot;Notes on rtl-sdr source code &#8211; first impressions&quot;\" \/>\n<meta property=\"og:url\" content=\"https:\/\/reactivemusic.net\/?p=8373\" \/>\n<meta property=\"og:site_name\" content=\"reactive music\" \/>\n<meta property=\"article:published_time\" content=\"2013-12-04T16:01:54+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2014-06-15T06:50:58+00:00\" \/>\n<meta name=\"author\" content=\"Tom Zicarelli\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Tom Zicarelli\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"1 minute\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"Article\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373#article\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373\"},\"author\":{\"name\":\"Tom Zicarelli\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/#\\\/schema\\\/person\\\/56224d281582df7e5518e037ca63e571\"},\"headline\":\"Notes on rtl-sdr source code &#8211; first impressions\",\"datePublished\":\"2013-12-04T16:01:54+00:00\",\"dateModified\":\"2014-06-15T06:50:58+00:00\",\"mainEntityOfPage\":{\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373\"},\"wordCount\":157,\"keywords\":[\"portfolio\",\"radio\",\"SDR\",\"software defined radio\"],\"articleSection\":[\"development\",\"DSP\"],\"inLanguage\":\"en-US\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373\",\"url\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373\",\"name\":\"Notes on rtl-sdr source code - first impressions - reactive music\",\"isPartOf\":{\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/#website\"},\"datePublished\":\"2013-12-04T16:01:54+00:00\",\"dateModified\":\"2014-06-15T06:50:58+00:00\",\"author\":{\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/#\\\/schema\\\/person\\\/56224d281582df7e5518e037ca63e571\"},\"breadcrumb\":{\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373#breadcrumb\"},\"inLanguage\":\"en-US\",\"potentialAction\":[{\"@type\":\"ReadAction\",\"target\":[\"https:\\\/\\\/reactivemusic.net\\\/?p=8373\"]}]},{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/?p=8373#breadcrumb\",\"itemListElement\":[{\"@type\":\"ListItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/reactivemusic.net\\\/\"},{\"@type\":\"ListItem\",\"position\":2,\"name\":\"Notes on rtl-sdr source code &#8211; first impressions\"}]},{\"@type\":\"WebSite\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/#website\",\"url\":\"https:\\\/\\\/reactivemusic.net\\\/\",\"name\":\"reactive music\",\"description\":\"\",\"potentialAction\":[{\"@type\":\"SearchAction\",\"target\":{\"@type\":\"EntryPoint\",\"urlTemplate\":\"https:\\\/\\\/reactivemusic.net\\\/?s={search_term_string}\"},\"query-input\":{\"@type\":\"PropertyValueSpecification\",\"valueRequired\":true,\"valueName\":\"search_term_string\"}}],\"inLanguage\":\"en-US\"},{\"@type\":\"Person\",\"@id\":\"https:\\\/\\\/reactivemusic.net\\\/#\\\/schema\\\/person\\\/56224d281582df7e5518e037ca63e571\",\"name\":\"Tom Zicarelli\",\"image\":{\"@type\":\"ImageObject\",\"inLanguage\":\"en-US\",\"@id\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g\",\"url\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g\",\"contentUrl\":\"https:\\\/\\\/secure.gravatar.com\\\/avatar\\\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g\",\"caption\":\"Tom Zicarelli\"},\"sameAs\":[\"http:\\\/\\\/tomzicarelli.com\"],\"url\":\"https:\\\/\\\/reactivemusic.net\\\/?author=2\"}]}<\/script>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"Notes on rtl-sdr source code - first impressions - reactive music","robots":{"index":"index","follow":"follow","max-snippet":"max-snippet:-1","max-image-preview":"max-image-preview:large","max-video-preview":"max-video-preview:-1"},"canonical":"https:\/\/reactivemusic.net\/?p=8373","og_locale":"en_US","og_type":"article","og_title":"Notes on rtl-sdr source code - first impressions - reactive music","og_description":"I did a quick read of source code (rtl-fm.c) today. Basically it opens an input stream of IQ samples from the rtl-sdr device, demodulates filters, and outputs audio. Other than usual madness with threads and locking &#8211; the code is fairly straightforward. Not well commented &#8211; but clear enough that we could extract the input &hellip; Continue reading \"Notes on rtl-sdr source code &#8211; first impressions\"","og_url":"https:\/\/reactivemusic.net\/?p=8373","og_site_name":"reactive music","article_published_time":"2013-12-04T16:01:54+00:00","article_modified_time":"2014-06-15T06:50:58+00:00","author":"Tom Zicarelli","twitter_card":"summary_large_image","twitter_misc":{"Written by":"Tom Zicarelli","Est. reading time":"1 minute"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/reactivemusic.net\/?p=8373#article","isPartOf":{"@id":"https:\/\/reactivemusic.net\/?p=8373"},"author":{"name":"Tom Zicarelli","@id":"https:\/\/reactivemusic.net\/#\/schema\/person\/56224d281582df7e5518e037ca63e571"},"headline":"Notes on rtl-sdr source code &#8211; first impressions","datePublished":"2013-12-04T16:01:54+00:00","dateModified":"2014-06-15T06:50:58+00:00","mainEntityOfPage":{"@id":"https:\/\/reactivemusic.net\/?p=8373"},"wordCount":157,"keywords":["portfolio","radio","SDR","software defined radio"],"articleSection":["development","DSP"],"inLanguage":"en-US"},{"@type":"WebPage","@id":"https:\/\/reactivemusic.net\/?p=8373","url":"https:\/\/reactivemusic.net\/?p=8373","name":"Notes on rtl-sdr source code - first impressions - reactive music","isPartOf":{"@id":"https:\/\/reactivemusic.net\/#website"},"datePublished":"2013-12-04T16:01:54+00:00","dateModified":"2014-06-15T06:50:58+00:00","author":{"@id":"https:\/\/reactivemusic.net\/#\/schema\/person\/56224d281582df7e5518e037ca63e571"},"breadcrumb":{"@id":"https:\/\/reactivemusic.net\/?p=8373#breadcrumb"},"inLanguage":"en-US","potentialAction":[{"@type":"ReadAction","target":["https:\/\/reactivemusic.net\/?p=8373"]}]},{"@type":"BreadcrumbList","@id":"https:\/\/reactivemusic.net\/?p=8373#breadcrumb","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https:\/\/reactivemusic.net\/"},{"@type":"ListItem","position":2,"name":"Notes on rtl-sdr source code &#8211; first impressions"}]},{"@type":"WebSite","@id":"https:\/\/reactivemusic.net\/#website","url":"https:\/\/reactivemusic.net\/","name":"reactive music","description":"","potentialAction":[{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https:\/\/reactivemusic.net\/?s={search_term_string}"},"query-input":{"@type":"PropertyValueSpecification","valueRequired":true,"valueName":"search_term_string"}}],"inLanguage":"en-US"},{"@type":"Person","@id":"https:\/\/reactivemusic.net\/#\/schema\/person\/56224d281582df7e5518e037ca63e571","name":"Tom Zicarelli","image":{"@type":"ImageObject","inLanguage":"en-US","@id":"https:\/\/secure.gravatar.com\/avatar\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g","url":"https:\/\/secure.gravatar.com\/avatar\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g","contentUrl":"https:\/\/secure.gravatar.com\/avatar\/0da58cf21a2707dd335b204b8ed3cd9194dcbf9d9814ac5d71195a65c76c8a72?s=96&d=mm&r=g","caption":"Tom Zicarelli"},"sameAs":["http:\/\/tomzicarelli.com"],"url":"https:\/\/reactivemusic.net\/?author=2"}]}},"_links":{"self":[{"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/posts\/8373","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8373"}],"version-history":[{"count":4,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/posts\/8373\/revisions"}],"predecessor-version":[{"id":8376,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=\/wp\/v2\/posts\/8373\/revisions\/8376"}],"wp:attachment":[{"href":"https:\/\/reactivemusic.net\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8373"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8373"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/reactivemusic.net\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8373"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}