mirror of https://bitbucket.org/ausocean/av.git
68 lines
1.9 KiB
Go
68 lines
1.9 KiB
Go
/*
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DESCRIPTION
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A motion filter that has a variable frame rate. When motion is detected,
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the filter sends all frames and when it is not, the filter sends frames
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at a reduced rate, as set by a parameter.
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AUTHORS
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Scott Barnard <scott@ausocean.org>
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LICENSE
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vfps.go is Copyright (C) 2019 the Australian Ocean Lab (AusOcean)
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It is free software: you can redistribute it and/or modify them
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under the terms of the GNU General Public License as published by the
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Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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It is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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You should have received a copy of the GNU General Public License
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in gpl.txt. If not, see http://www.gnu.org/licenses.
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*/
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package filter
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import (
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"io"
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)
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// VariableFPS is a filter that has a variable frame rate. When motion is
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// detected, the filter sends all frames and when it is not, the filter
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// sends frames at a reduced framerate.
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type VariableFPS struct {
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filter Filter
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dst io.WriteCloser
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frames uint
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count uint
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}
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// NewVariableFPS returns a pointer to a new VariableFPSFilter struct.
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func NewVariableFPS(dst io.WriteCloser, minFPS float64, filter Filter) *VariableFPS {
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frames := uint(25 / minFPS)
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return &VariableFPS{filter, dst, frames, 0}
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}
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// Implements io.Writer.
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// Write applies the motion filter to the video stream. Frames are sent
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// at a reduced frame rate, except when motion is detected, then all frames
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// with motion are sent.
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func (v *VariableFPS) Write(f []byte) (int, error) {
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v.count = (v.count + 1) % v.frames
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if v.count == 0 {
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return v.dst.Write(f)
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}
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return v.filter.Write(f)
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}
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// Implements io.Closer.
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// Close calls the motion filter's Close method.
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func (v *VariableFPS) Close() error {
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return v.filter.Close()
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}
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