Supported sound formats

This is a list of supported sound formats.

Format	Usual file extension
RIFF WAVE	.wav
Native FLAC	.flac

Please note that due to its 3D positional nature, OpenBVE will convert multi-channel audio to mono upon loading, so there is no point in providing multi-channel audio in the first place. For multi-channel audio, OpenBVE discards silent channels and tries to detect constructive or destructive interference in the mixed version of the remaining channels. If interference is detected, the first non-silent channel in the file is used, otherwise the mixed channel.

■ RIFF WAVE format

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WAVE files are supported, which technically are RIFF (or RIFX) container files with the WAVE format type. WAVE itself allows different formats, of which only a subset are supported. These are:

Format	Sample rate	Bitrate	Channels
PCM	any	any	any
Microsoft ADPCM	any	4 bits	any

Sample rate refers to the number of samples per second per channel. Bitrate refers to the number of bits per sample per channel.

■ Native FLAC format

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All native FLAC files are supported with the following (in practice rarely occuring) exceptions:

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Changing the sample rate in the middle of the file is not supported.

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Negative predictor shifts are not supported.

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MD5 checks are skipped for bit rates other than 8, 16 or 24.

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Further information about these formats from a programmer's point of view can be found on these external sites:

General information about RIFF, WAVE and PCM:
➟ http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/Docs/riffmci.pdf

Information about Microsoft ADPCM:
➟ http://icculus.org/SDL_sound/downloads/external_documentation/wavecomp.htm

Official documentation on FLAC:
➟ http://flac.sourceforge.net/documentation.html

Additional documentation on FLAC:
➟ http://home.comcast.net/~b.langenb/audioformats_letter.pdf