43 lines
1.3 KiB
Lua
43 lines
1.3 KiB
Lua
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local pcm = {}
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-- Reads a file containing signed 8-bit PCM audio data, and converts it into a list of buffers to play.
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function pcm.readFile(filename)
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if not fs.exists(filename) then error("Audio file " .. filename .. " doesn't exist.") end
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if fs.isDir(filename) then error("Cannot read audio from directory: " .. filename) end
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local frames = {}
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local currentFrame = {}
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local currentFrameSampleCount = 0
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local file = fs.open(filename, "rb")
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while true do
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local n = file.read()
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if n == nil then break end
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if n > 127 then n = n - 256 end
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table.insert(currentFrame, n)
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currentFrameSampleCount = currentFrameSampleCount + 1
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if currentFrameSampleCount == (128 * 1024) then
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table.insert(frames, currentFrame)
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currentFrame = {}
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currentFrameSampleCount = 0
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end
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end
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file.close()
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if currentFrameSampleCount > 0 then
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table.insert(frames, currentFrame)
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end
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return frames
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end
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function pcm.playFrames(speaker, frames)
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for i = 1, #frames do
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while not speaker.playAudio(frames[i]) do
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os.pullEvent("speaker_audio_empty")
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end
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end
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end
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function pcm.playFile(speaker, filename)
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local frames = pcm.readFile(filename)
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pcm.playFrames(frames)
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end
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return pcm
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