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https://github.com/pion/mediadevices.git
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37 lines
1.3 KiB
Go
37 lines
1.3 KiB
Go
package frame
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import (
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"encoding/binary"
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"fmt"
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"image"
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"image/color"
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)
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func decodeZ16(frame []byte, width, height int) (image.Image, func(), error) {
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expectedSize := 2 * (width * height)
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if expectedSize != len(frame) {
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return nil, func() {}, fmt.Errorf("frame length (%d) not expected size (%d)", len(frame), expectedSize)
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}
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img := image.NewGray16(image.Rect(0, 0, width, height))
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/*
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v4l specifies images in terms of series of lines which is perplexing because the
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example in https://www.kernel.org/doc/html/v5.9/userspace-api/media/v4l/pixfmt-z16.html
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seems to swap the subscript of each depth value.
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Clear example:
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Width: 3, Height: 4
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[Z_low(x_0,y_0), Z_high(x_0,y_0), Z_low(x_1,y_0), Z_high(x_1,y_0), Z_low(x_2,y_0), Z_high(x_2,y_0),
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Z_low(x_0,y_1), Z_high(x_0,y_1), Z_low(x_1,y_1), Z_high(x_1,y_1), Z_low(x_2,y_1), Z_high(x_2,y_1),
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Z_low(x_0,y_2), Z_high(x_0,y_2), Z_low(x_1,y_2), Z_high(x_1,y_2), Z_low(x_2,y_2), Z_high(x_2,y_2),
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Z_low(x_0,y_3), Z_high(x_0,y_3), Z_low(x_1,y_3), Z_high(x_1,y_3), Z_low(x_2,y_3), Z_high(x_2,y_3)]
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*/
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for x := 0; x < width; x++ {
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for y := 0; y < height; y++ {
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idx := 2 * (x + (y * width))
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z := binary.LittleEndian.Uint16(frame[idx : idx+2])
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img.SetGray16(x, y, color.Gray16{Y: z})
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}
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}
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return img, func() {}, nil
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}
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