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Ogg Vorbis, The Open Source File Format

By Stephanie Ciccarelli

August 8, 2006

Comments (2)

Like Open Source? Ogg Vorbis ( .ogg ) is for you.

Earlier we covered AAC as a potential replacement for the omnipresent MP3 file format. Open Source fans will be familiar with Ogg Vorbis, commonly known as "ogg".

Here's what the Adobe Support Centre has this to say re: Audition 2.0

"Ogg Vorbis (.ogg)

The Ogg Vorbis format is comparable to other formats used to store and play digital music, such as MP3, VQF, and AAC. Unlike those formats, however, Ogg Vorbis is license-free, so itâ€™s often used for commercial video games.

When you save an OGG file, you can either select one of three basic encoding options, or use advanced settings for detailed control:

VBR (Target Bitrate) Lets you specify the target bitrate in kilobits per second. Maintains audio quality by varying the bitrate depending on the complexity of the audio being encoded. This method can maintain higher audio quality, although file size is not as predictable as with Fixed Bitrate encoding.

VBR (Quality Index) Like VBR (Target Bitrate), but lets you specify quality on a scale of 0 to 10.
Fixed Bitrate Varies the quality level as needed to ensure that the bit rate stays at the specified rate. This method makes a consistently sized file, although the quality may not be as high as with Variable Bit Rate encoding.

Use Advanced Settings Enables the following options:

Minimum, Target, and Maximum Bitrate Let you precisely specify compression settings.

Bit Reservoir Size Specifies the amount of surplus bits to reserve during variable bitrate encoding.

Bit Reservoir Bias Determines how surplus bits are distributed. Lower settings store surplus bits during consistent audio, instead applying those bits to transient peaks and troughs. Higher settings store surplus bits during transients, instead applying those bits to consistent audio. The default setting, 0.2, slightly favors transients.

Impulse Noise Floor Sets the amplitude above which the encoder looks for artifacts in transient peaks. Lower noise floors improve transient response but increase bitrate.

Damping Time Determines how quickly bitrate returns to the targeted average. At lower settings, bitrate varies less, but audio quality suffers; at higher settings, bitrate varies more, but audio quality improves.

Lowpass Filter Specifies the highest frequency to retain in the encoded file."

Are there any Open Source supporters out there who can share their experience with Ogg?

Best,

Stephanie