You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: config.go
    path of file: ./repos/photoprism/internal/ffmpeg
    
    the code of the file until where you have to start completion: package ffmpeg

import "fmt"

// Options represents transcoding options.
type Options struct {
	Bin      string
	Encoder  AvcEncoder
	Size     int
	
    
func (o Options) VideoFilter(format PixelFormat) string {
	// scale specifies the FFmpeg downscale filter, see http://trac.ffmpeg.org/wiki/Scaling.
	if format == "" {
		return fmt.Sprintf("scale='if(gte(iw,ih), min(%d, iw), -2):if(gte(iw,ih), -2, min(%d, ih))'", o.Size, o.Size)
	} else if format == FormatQSV {
		return fmt.Sprintf("scale_qsv=w='if(gte(iw,ih), min(%d, iw), -1)':h='if(gte(iw,ih), -1, min(%d, ih))'", o.Size, o.Size)
	} else {
		return fmt.Sprintf("scale='if(gte(iw,ih), min(%d, iw), -2):if(gte(iw,ih), -2, min(%d, ih))',format=%s", o.Size, o.Size, format)
	}
}