<?xml version="1.0" encoding="UTF-8"?> <rss version="2.0" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:wfw="http://wellformedweb.org/CommentAPI/" xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:atom="http://www.w3.org/2005/Atom" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:slash="http://purl.org/rss/1.0/modules/slash/" ><channel><title>Kevin Deldycke &#187; VLC</title> <atom:link href="http://kevin.deldycke.com/tag/vlc/feed/" rel="self" type="application/rss+xml" /><link>http://kevin.deldycke.com</link> <description>Free software engineer &#38; wannabe videomaker</description> <lastBuildDate>Fri, 03 Feb 2012 19:08:27 +0000</lastBuildDate> <language>en</language> <sy:updatePeriod>hourly</sy:updatePeriod> <sy:updateFrequency>1</sy:updateFrequency> <generator>http://wordpress.org/?v=3.3.1</generator> <item><title>A/V sync problems: VLC better than Mencoder</title><link>http://kevin.deldycke.com/2006/04/av-sync-problems-vlc-better-than-mencoder/</link> <comments>http://kevin.deldycke.com/2006/04/av-sync-problems-vlc-better-than-mencoder/#comments</comments> <pubDate>Sun, 09 Apr 2006 22:30:38 +0000</pubDate> <dc:creator>Kev</dc:creator> <category><![CDATA[English]]></category> <category><![CDATA[Linux]]></category> <category><![CDATA[mencoder]]></category> <category><![CDATA[Video]]></category> <category><![CDATA[VLC]]></category><guid isPermaLink="false">http://kevin.deldycke.com/2006/04/10/av-sync-problems-vlc-better-than-mencoder/</guid> <description><![CDATA[Today I tried to transcode a bunch of videos using my favorite script. I need to do this because the videos produced with my cheap camera use Mjpeg as video codec and raw-data as audio codec. This result of incredible &#8230; <a href="http://kevin.deldycke.com/2006/04/av-sync-problems-vlc-better-than-mencoder/">Continue reading <span class="meta-nav">&#8594;</span></a>]]></description> <content:encoded><![CDATA[<p>Today I tried to transcode a bunch of videos using my favorite script. I need to do this because the videos produced with my cheap camera use Mjpeg as video codec and raw-data as audio codec. This result of incredible large files. To share my videos with friends, I transcode them to mpeg4/mp3 files. This is all the dirty work my script is supposed to handle.</p><p>Unfortunately I didn&#8217;t use it since I upgraded Mandriva from 2005 to the 2006 release. As you can guess, it wasn&#8217;t working: mencoder gave me the following &#8220;Audio LAVC, couldn&#8217;t find encoder for codec mp3&#8243; error message. First, I though it was because of a bad version of ffmpeg. Looking at the source RPM from PLF repository gave me the proof that my version was compiled with the right options.</p><p>To bypass this problems, I used the -mp3lame as output audio codec. This introduced horrible A/V sync. <img src='http://kevin.deldycke.com/wp-includes/images/smilies/icon_sad.gif' alt=':(' class='wp-smiley' /> For 3 hours, I tried to play with mencoder options without success. I was completetly desesperated&#8230; until I tried VLC. In less than 10 minutes I was able to get the expected result: perfect A/V sync movie file !</p><p>Thanks to the <a href="http://wiki.videolan.org/index.php/Main_Page">VLC wiki</a>, I also discovered the h264 video codec, which is a good codec for low bitrates. Even if it produce bigger files compared to my older method (the latter can be found in <a href="http://kevin.deldycke.com/static/scripts/avi2mp4-2005_10_02.py">the first version of the script</a>), the quality is very awesome and video artefacts (ringings and blockings) are so reduced that it&#8217;s now very hard to distinguish. So I decided to use h264 in the <a href="http://kevin.deldycke.com/static/scripts/avi2mp4-2006_04_09.py">new version of my script</a>.</p><p>There is still an inconvenient of using VLC instead of mencoder: VLC is transcoded at real time ! I tried the &#8220;hurry-up&#8221; parameters without effects. This is sad but acceptable, since my goal is to archive my tiny videos.</p><p>To summarize, here is the command line I use to do transcoding via VLC:</p><pre class="brush: bash; title: ; notranslate">
vlc --sout-all &quot;input_video.avi&quot; :sout='#transcode{vcodec=h264, acodec=mp3, ab=32,channels=1, audio-sync}:std{access=file, mux=mp4, url=&quot;output_video.mp4&quot;}' vlc:quit -I dummy
</pre><p>This command is far from perfect and I plan to dig into VLC help to tune h264 codec.</p> ]]></content:encoded> <wfw:commentRss>http://kevin.deldycke.com/2006/04/av-sync-problems-vlc-better-than-mencoder/feed/</wfw:commentRss> <slash:comments>1</slash:comments> </item> </channel> </rss>
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