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• Unable to manually parse the HEVC video with alpha [closed]

  17 novembre 2023, par leo

  I'm trying to parse the bitstream of HEVC video with alpha on linux(specific video format reference WWDC2019 : https://developer.apple.com/videos/play/wwdc2019/506).

  


  Taking the 'puppets_with_alpha_hevc.mov' file from 'Using HEVC Video with Alpha' as an example, I would first extract the HEVC bitstream, then parse its fields. When it comes to the VPS field, as I reach the vps_extension, I find that the bitstream in 'puppets_with_alpha_hevc.mov' does not conform to the HEVC standard document, preventing further parsing.

  


  The extracted HEVC bitstream binary is shown in the following image.

I analyzed the VPS part of the bitstream, and the vps_extension field should start from 0x3F. However, I encountered an issue when parsing up to 0xA4, as shown in the picture, and could not continue with the parsing.


  


  I'm not sure at which step the error occurred, but it should be somewhere between the 0x3F on line 28 and 0xA4 on line 34. Is anyone familiar with HEVC with alpha ? Could you provide some insights or tips for analysis ?

  


• Ffmeg to convert images to video

  30 octobre 2022, par WILT

  I have this kind of named files, as shown in the image. How can i use ffmpeg to make apple pro res video out of them.


  


  i do not know what to try

  


• Swift A script of macOS is not running on the M2 chip ?

  15 avril 2024, par Muhammad Danish Qureshi

  I am making a macOS app using SwiftUI, app is working fine on mac Intel chip, mac Apple M1 chip but not working on the mac M2 chip.
Below is the following code which is crashing on M2 chip for force unwrapping the data in String(data: data!, encoding: .utf8).

  


  I know that force unwrap is not suitable, but for testing purpose I am doing force unwrap.

  


  When I run the which ffmpeg in terminal it provides the path in result, no matter which mac terminal is (it always return actual path of ffmpeg), but when run this command from the swift Program it does not found anything and got crashed on apple M2 chip.

  


  My actual scenario (or requirement) is I need to get the path using the command which ffmpeg and write that path in the file on macOS app.

  


  Kindly guide me why the code is crashing or not providing the actual path.

  


  func findFFmpegPath() -> String? {
            let task = Process()
            task.launchPath = "/bin/bash" // Path to bash shell
            task.arguments = ["-l", "-c", "which ffmpeg"] // Execute "which ffmpeg" command
    let pipe = Pipe()
    task.standardOutput = pipe
    task.standardError = pipe // Capture any errors as well

    do {
        try task.run()
        let data = try pipe.fileHandleForReading.readToEnd()
        let output = String(data: data!, encoding: .utf8)
        print("data:\(data)\n\(output)\n\(output?.trimmingCharacters(in: .whitespacesAndNewlines))")
        return output?.trimmingCharacters(in: .whitespacesAndNewlines)
    } catch {
        print("Error running task: \(error)")
        return nil
    }
}


  


  When I run which ffmpeg in the terminal it gives me path correctly, See the screenshot bleow.

  


  

  


  When I run the /bin/bash -l -c "which ffmpeg" in the M2 than I got this result.

  


  

  


  When I run the /bin/bash -l -c "which ffmpeg" in the Apple M1 than I got this result.

  


  

  


  Getting desired result in the terminal, but not getting result from the Swift Program.