{"id":1093,"date":"2009-02-12T21:07:42","date_gmt":"2009-02-13T05:07:42","guid":{"rendered":"http:\/\/multimedia.cx\/eggs\/?p=1093"},"modified":"2009-02-12T21:07:42","modified_gmt":"2009-02-13T05:07:42","slug":"silverlight-codecpack","status":"publish","type":"post","link":"https:\/\/multimedia.cx\/eggs\/silverlight-codecpack\/","title":{"rendered":"Silverlight Codecpack"},"content":{"rendered":"<p>I was visiting ossguy&#8217;s blog today when I noticed that he took a small break from the usual &#8220;Free Software \u00dcber Alles&#8221; rhetoric to <a href=\"http:\/\/ossguy.com\/?p=266\">post a useful investigation of the Microsoft binary codec pack<\/a> that corresponds to <a href=\"http:\/\/www.mono-project.com\/Moonlight\">Moonlight<\/a>, Linux&#8217;s free implementation of <a href=\"http:\/\/silverlight.net\/\">Silverlight<\/a>. At first, I was surprised to hear that this codec pack was finally available&#8211; I didn&#8217;t think it was going to be generally available until Moonlight&#8217;s official release. A little digging revealed that <a href=\"http:\/\/tirania.org\/blog\/archive\/2009\/Feb-11.html\">Moonlight 1.0 was officially released yesterday<\/a>. I wondered why I hadn&#8217;t seen anything about this on any major Linux news sites yet.<\/p>\n<p><em>Apparently, no one cares.<\/em><\/p>\n<p>Well, I care, insofar as this is another way to study some codecs. I think it&#8217;s really slick that the codec pack is one monolithic, relatively small, binary blob that contains all the proprietary codecs needed to support Silverlight. ossguy&#8217;s post details 2 more-or-less direct download links:<\/p>\n<ul>\n<li>x86_32 version: silverlight-media-pack-linux-x86-5-1.so @ <a href=\"http:\/\/go.microsoft.com\/fwlink\/?LinkId=133186\">http:\/\/go.microsoft.com\/fwlink\/?LinkId=133186<\/a><\/li>\n<li>x86_64 version: silverlight-media-pack-linux-x64-5-1.so @ <a href=\"http:\/\/go.microsoft.com\/fwlink\/?LinkId=133816\">http:\/\/go.microsoft.com\/fwlink\/?LinkId=133816<\/a><\/li>\n<\/ul>\n<p>I see that compn is already on the case, <a href=\"http:\/\/wiki.multimedia.cx\/index.php?title=Talk:Microsoft\">identifying the precise codec formats<\/a> that this blob is designed to handle: wma1, wma2, wma3, wmv1, wmv2, wmv3, wmav, wvc1, and mp3. So, really, nothing interesting for our cause. Almost all of those formats are already supported in <a href=\"http:\/\/ffmpeg.org\/\">FFmpeg<\/a>. The one that isn&#8217;t &#8212; WMA3 &#8212; is in progress via a Summer of Code project. Who knows? Perhaps this codec pack could yield some new intelligence. But I tend to think the previous binary decoder released for Linux &#8212; packaged with Linspire &#8212; was pretty thorough in its presentation of symbols.<\/p>\n<p>This codec pack is pretty thorough in the symbols department as well. Run &#8216;strings&#8217; against the blob to see the ASCII strings. Filter the output through &#8216;c++filt&#8217; as this will demangle (official technical jargon) the C++-style names:<\/p>\n<pre>\r\n  strings file.so | c++filt\r\n<\/pre>\n<p>And if you want to disassemble the binary, here is a little something I wrote up regarding the <a href=\"http:\/\/wiki.multimedia.cx\/index.php?title=Objdump\">bare essentials of &#8216;objdump&#8217;<\/a> as applied to reverse engineering work.<\/p>\n<p>At the very least, I can see this codec pack being useful for hooking up to FFmpeg in order to gather a baseline for profiling to see how FFmpeg&#8217;s decoders stack up. Further, I should be able to use it to decode reference samples to verify how close FFmpeg decodes, e.g., WMA 1\/2 data to the original.<\/p>\n<p>Whatever the case, I have started a <a href=\"http:\/\/wiki.multimedia.cx\/index.php?title=Moonlight_Codec_Pack\">MultimediaWiki page to describe the API<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>The new Moonlight codec pack has lots of symbols; too bad we already know most of the codecs inside<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[154,153],"class_list":["post-1093","post","type-post","status-publish","format-standard","hentry","category-reverse-engineering","tag-moonlight","tag-silverlight"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/posts\/1093","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/comments?post=1093"}],"version-history":[{"count":6,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/posts\/1093\/revisions"}],"predecessor-version":[{"id":1099,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/posts\/1093\/revisions\/1099"}],"wp:attachment":[{"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/media?parent=1093"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/categories?post=1093"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/multimedia.cx\/eggs\/wp-json\/wp\/v2\/tags?post=1093"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}