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Finding the width and height of Ogg Theora videos

Subhash Chandran — Fri, 31 Jul 2009 09:43:41 +0000

When placing Ogg Theora video files in your site using HTML5 tags, you can optionally specify the width and height of the videos. But how do you find the width and height? Use the tool ogginfo:

$ ogginfo video.ogg

Text-to-speech in Linux

Subhash Chandran — Fri, 31 Jul 2009 08:55:14 +0000

Festival is an interesting OpenSource project for converting text-to-speech in Linux environment. It has a commandline tool text2wave which converts, guess what, text to voice in wave format. Simple usage:

$ echo "Hello World" | text2wave > a.wav

Wave files are uncompressed, and occupy lot of space. To encode to Ogg Vorbis format:

$ oggenc a.wav

This will create a.ogg in the current directory.

Desktop Video Capture in Linux

Subhash Chandran — Wed, 15 Jul 2009 04:00:27 +0000

recordmydesktop is a powerful screencasting commandline tool for Linux. To capture the screen:

$ recordmydesktop

Press Ctrl+C to quit capturing. The captured video will be encoded in Ogg Theora format and saved as out.ogv (if out.ogv exists, as out-1.ogv and so on). To save the file in another name, say myout.ogv:

$ recordmydesktop myout.ogv

There is also a GTK frontend for recordmydesktop. To launch it:

$ gtk-recordMyDesktop

Encoding to Ogg Theora Format: For use in HTML5

Subhash Chandran — Tue, 14 Jul 2009 09:08:58 +0000

To encode a video file for use in HTML5 video compatible browser (firefox 3.5 and above supports HTML5 video), use the command:

$ ffmpeg -i in.flv -vcodec libtheora -sameq \
   -acodec libvorbis -ac 2 -sameq out.ogg

Finally use it in your page:


Your browser does not support HTML5 video.

Reference: HTML 5 Tag.

Video format conversion in Linux

Subhash Chandran — Wed, 24 Jun 2009 11:13:43 +0000

To stream video content using Video View Portlet, I had to re-encode some videos to flv format. This is pretty simple in Linux:

$ mencoder -oac copy -ovc lavc -o out.flv in.avi

-oac means Output Audio Codec and -ovc means Output Video Codec. The various options for -oac:

`copy`	no encoding, just streamcopy.
`pcm`	Encode to uncompressed PCM.
`mp3lame`	Encode to MP3 (using LAME).
`lavc`	Encode with a libavcodec codec.

The options for -ovc:

`copy`	no encoding, just streamcopy.
`raw`	Encode to an arbitrary uncompressed format (use ’-vf format’ to select).
`lavc`	Encode with a libavcodec codec.