84 lines
2.4 KiB
Lua
84 lines
2.4 KiB
Lua
ardour { ["type"] = "Snippet", name = "Set Region Gain" }
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function factory () return function ()
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-- get Editor GUI Selection
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-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:Selection
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local sel = Editor:get_selection ()
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-- allocate a buffer (float* in C)
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-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:DSP:DspShm
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local cmem = ARDOUR.DSP.DspShm (8192)
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-- prepare undo operation
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Session:begin_reversible_command ("Lua Region Gain")
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local add_undo = false -- keep track if something has changed
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-- iterate over selected regions
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-- http://manual.ardour.org/lua-scripting/class_reference/#ArdourUI:RegionSelection
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for r in sel.regions:regionlist ():iter () do
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-- test if it's an audio region
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if r:to_audioregion ():isnil () then
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goto next
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end
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-- to read the Region data, we use the Readable interface of the Region
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-- http://manual.ardour.org/lua-scripting/class_reference/#ARDOUR:AudioReadable
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local a = r.to_audioregion
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local rd = a:to_readable ()
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local n_samples = rd:readable_length ()
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local n_channels = rd:n_channels ()
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local peak = 0 -- the audio peak to be calculated
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-- iterate over all channels in Audio Region
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for c = 0, n_channels -1 do
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local pos = 0
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repeat
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-- read at most 8K samples of channel 'c' starting at 'pos'
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local s = rd:read (cmem:to_float (0), pos, 8192, c)
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pos = pos + s
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-- access the raw audio data
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-- http://manual.ardour.org/lua-scripting/class_reference/#C:FloatArray
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local d = cmem:to_float (0):array()
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-- iterate over the audio sample data
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for i = 1, s do
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if math.abs (d[i]) > peak then
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peak = math.abs (d[i])
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end
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end
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until s < 8192
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assert (pos == n_samples)
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end
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if (peak > 0) then
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print ("Region:", r:name (), "peak:", 20 * math.log (peak) / math.log(10), "dBFS")
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else
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print ("Region:", r:name (), " is silent")
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end
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-- normalize region
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if (peak > 0) then
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-- prepare for undo
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r:to_stateful ():clear_changes ()
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-- apply gain
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r:to_audioregion (): set_scale_amplitude (1 / peak)
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-- save changes (if any) to undo command
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if not Session:add_stateful_diff_command (r:to_statefuldestructible ()):empty () then
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add_undo = true
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end
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end
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::next::
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end
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-- all done. now commit the combined undo operation
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if add_undo then
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-- the 'nil' command here means to use all collected diffs
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Session:commit_reversible_command (nil)
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else
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Session:abort_reversible_command ()
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end
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end end
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