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Diffstat (limited to 'docs/ambisonics.txt')
| -rw-r--r-- | docs/ambisonics.txt | 41 |
1 files changed, 17 insertions, 24 deletions
diff --git a/docs/ambisonics.txt b/docs/ambisonics.txt index 2d94427e..b03e3bed 100644 --- a/docs/ambisonics.txt +++ b/docs/ambisonics.txt @@ -79,30 +79,23 @@ Soft (or any other OpenAL implementation that wishes to) can render using Ambisonics and decode the ambisonic mix for a high level of accuracy over what simple pan-pot could provide. -This is effectively what the high-quality mode option does, when given an -appropriate decoder configuation for the playback channel layout. 3D rendering -and effect mixing is done to an ambisonic buffer, which is later decoded for -output utilizing the benefits available to ambisonic processing. - -The basic, non-high-quality, renderer uses similar principles, however it skips -the frequency-dependent processing (so low frequency sounds are treated the -same as high frequency sounds) and does some creative manipulation of the -involved math to skip the intermediate ambisonic buffer, rendering more -directly to the output while still taking advantage of all the available -speakers to reconstruct the sound wave. This method trades away some playback -quality for less memory and processor usage. - -In addition to providing good support for surround sound playback, Ambisonics -also has benefits with stereo output. 2-channel UHJ is a stereo-compatible -format that encodes some surround sound information using a wide-band 90-degree -phase shift filter. It works by taking a B-Format signal, and deriving a -frontal stereo mix with the rear sounds attenuated and filtered in with it. -Although the result is not as good as 3-channel (2D) B-Format, it has the -distinct advantage of only using 2 channels and being compatible with stereo -output. This means it will sound just fine when played as-is through a normal -stereo device, or it may optionally be fed to a properly configured surround -sound receiver which can extract the encoded information and restore some of -the original surround sound signal. +When given an appropriate decoder configuration for the channel layout, the +ambisonic mix can be decoded utilizing the benefits available to ambisonic +processing, including frequency-dependent processing and near-field effects. +Without a decoder configuration, the ambisonic mix can still be decoded for +good stereo or surround sound output, although without near-field effects as +there's no speaker distance information. + +In addition to surround sound output, Ambisonics also has benefits with stereo +output. 2-channel UHJ is a stereo-compatible format that encodes some surround +sound information using a wide-band 90-degree phase shift filter. This is +generated by taking the ambisonic mix and deriving a front-stereo mix with +with the rear sounds filtered in with it. Although the result is not as good as +3-channel (2D) B-Format, it has the distinct advantage of only using 2 channels +and being compatible with stereo output. This means it will sound just fine +when played as-is through a normal stereo device, or it may optionally be fed +to a properly configured surround sound receiver which can extract the encoded +information and restore some of the original surround sound signal. What Are Its Limitations? |