Calling a command line tool from Swift 4 macOS

🎤 General Discussion Swift
1

Hello,

I need to call ffmpeg from a Swift routine I have created but I am not sure how to get an NSImage returned. I have tried to use the ffmpeg libraries but this has proven to be more difficult than I thought (unless someone has gone this route successfully and wants to share with the rest of the class).

Ultimately, I need a thumbnail, a proxy file and the metadata from a given video at “itemPath” that will go into either a CoreData or Firebase db, but one thing at a time.

func CreateThumbnailFromURL(itemPath: URL) ->NSImage {
        
let task = Process()

task.launchPath = "/usr/local/bin/ffmpeg"

task.arguments = ["not sure what this is supposed to be"] // the arguments for ffmpeg: -ss 120 -v error -i itemPath -s 480x270 -frames:v 1 and return an NSImage

task.launch()
task.waitUntilExit() 
        
        
        return thumbnail
    }

Any ideas?

Thanks.

2

Okay, I got the call to work. I used the wrong variable for the output thumbnail path.

Unfortunately, I am stuck on how to turn the thumbnail file into an NSImage without first having to save the file.

Also, I need the error in order to use a generic thumbnail in case ffmpeg cannot parse properly parse the video file.

Any ideas?

Here is the final routine:

func CreateThumbnailFromURL(itemPath: URL) ->NSImage {
    
    let path = "/usr/local/bin/ffmpeg"
    
    let thumbnailName = itemPath.deletingPathExtension().lastPathComponent
    
    let thumbnailPath = "/Users/jimmybee/Pictures/thumbnails/" + thumbnailName + ".jpg"
    
    var thumbnail = NSImage()

    var arguments = ["-ss", "120", "-v", "error", "-i", itemPath.absoluteString.removingPercentEncoding as Any, "-s", "480x270", "-frames:v", "1", thumbnailPath] as [Any]
    
    let task = Process.launchedProcess(launchPath: path, arguments: arguments as! [String])
    task.waitUntilExit()
    
    return thumbnail
}