Converting File Formats

To convert an image from one format to another using imcopy, you must specify which file to convert, where the file is located, the format it should be converted to, and where to store the file on output.

Syntax

imcopy -f <output format> <in file name and path> <out file name and path> <start index> <stop index>

Example

imcopy -f tiff /usr/tmp/SGI/source%04d.sgi /usr/tmp/TIFF/dest%04d.tif 1 100

This operation converts the SGI images into TIFF images.

Converting 10-bit Cineon Images

Digital film scans often consist of logarithmic data. Because Backdraft Conform algorithms are optimized for linear data, a LUT is often used on import to convert the gamma and correct the logarithmic data for a linear data environment. Since Cineon images contain 10-bit logarithmic data, you need to use a LUT to convert the 10-bit logarithmic data to 8-, 10- or 12-bit linear. You can use one of the LUTs provided, or create a custom LUT and use it with imcopy to import Cineon files directly into the framestore. See Colour Management.

Extracting an Alpha Channel from an RGBA Image

You can use the -x option to extract the alpha channel from your RGBA image. The RGBA infile will be split into two RGB outfiles; the destination_alpha_filename file will contain only the alpha channel of the inRGBA_file, and the outRGB_file will contain only the RGB components of the inRGBA_file.

Syntax

imcopy -x noinvert <in RGBA file> <destination for RGB and alpha files> <start index> <stop index>

Example

imcopy -x noinvert /usr/tmp/SGI/source%04d.sgi

/usr/discreet/clip/stonefs/NTSC/MyLib@myclip 1 100

This example takes the SGI RGBA images in the sequence and creates two clips in the MyLib library on the NTSC project of the framestore stonefs.

On output, the clip myclip contains the RGB image, and the clip myclip_alpha contains the alpha channel of the original image.

Integrating an Alpha Channel into an RGB Image

You can use the -a option to combine an alpha (matte) infile and an RGB infile to produce an RGBA outfile.

Syntax

imcopy -a <in matte file> <in RGB file> <out RGBA file>

Example

imcopy -a /usr/discreet/clip/stonefs/NTSC/MyLib@myclip_alpha /usr/discreet/clip/stonefs/NTSC/MyLib@myclip /usr/tmp/SGI/dest%04d.sgi 1 100

This example takes the RGB data from myclip in the MyLib clip library in project NTSC on framestore stonefs, combines it with the matte clip myclip_alpha, and generates an SGI RGBA for the first 100 frames.

Cropping an Image

If you want to import a section of your source image only, you can specify the origin of this section with the -o (x position, y position) option. You can specify the size of this section with the -s (width, height) option.

The size of the internal buffer is specified with the -d (width, height) option. By default, the size of the internal buffer is the same as the width and height of the source image. If the buffer size differs from the source image, resize the selected rectangle from the source image into the internal buffer size using the -k (cropping type) option.

The -q option can be used to specify the quality of resizing: coarse, medium, quality or bicubic.

Cropping the Frames

You can crop the source frames using the -k option. The available options are as follows.

Adjusting Bit Depths

By default, the internal buffer has a depth of 8 bits. If your source image has a depth greater than 8 bits, you should specify an internal buffer depth of 12 bits using the -i 12 option to avoid truncating data to 8 bits per component. This changes the buffer depth from 8 bits to 12 bits.

Once the desired area of the source image has been cropped and resized and the bit depth has been converted into the internal buffer, the image is written to the destination. If the destination is an image file, the image file format will be the same as the input format. You can use the -f (image format) option to specify a different image format. By default, imcopy outputs images with 8-bit depth. Use the -e (bit depth) option to override the default setting.