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• How can I generate a metadata.mov file for higher-resolution Live Photos (e.g. 1440x2560) ?

  30 juillet, par brijesh patel

  I'm generating Live Photos programmatically for use as wallpapers on iOS. I'm using a known metadata.mov file bundled with the app (likely extracted from a working Live Photo with resolution 1080x1920). This setup works fine when I use a video of the same resolution.

  


  I'm using this open-source library to handle the video-to-LivePhoto conversion :
  
https://github.com/TouSC/Video2LivePhoto

  


  However, when I try using a higher-resolution video (e.g. 2560x1440) to avoid black bars on high-resolution devices (like iPhone 14 Pro Max), the Photos app shows the Live Photo, but the motion component doesn't work—it just says “Motion Not Available.”

  


  I believe the issue is that the static metadata.mov contains resolution-specific metadata, which prevents it from working correctly with other video sizes.

  


  


  • Tried changing the resolution of the video (e.g. 1440x2560, 1284x2778) – motion breaks.

    


  


  • Tried generating a new .mov file using FFmpeg with a silent video track, matching the new resolution – Live Photo not recognized or shows errors.

    


  


  • Tried modifying the existing metadata.mov with tools like FFmpeg, AtomicParsley, Bento4, and mp4box – resulting files often break the Live Photo entirely.

    


  


  • I expected to generate a valid metadata.mov (or similar track) that would support the custom resolution and restore Live Photo motion support.

    


  


  


  static func convertVideo(videoURL: URL, complete: @escaping (_ success: Bool, _ errorMessage: String?) -> Void) {
    print("start converting")
    
    guard let metaURL = Bundle.main.url(forResource: "metadata", withExtension: "mov") else {
        complete(false, "metadata.mov not found")
        return
    }

    let livePhotoSize = CGSize(width: 1440, height: 2560) // <-- updated resolution
    let livePhotoDuration = CMTime(value: 550, timescale: 600)
    let assetIdentifier = UUID().uuidString

    guard let documentPath = NSSearchPathForDirectoriesInDomains(.documentDirectory, .userDomainMask, true).first else {
        complete(false, "Document path not found")
        return
    }

    let durationPath = documentPath + "/duration.mp4"
    let acceleratePath = documentPath + "/accelerate.mp4"
    let resizePath = documentPath + "/resize.mp4"
    let finalPath = resizePath

    removeFileIfExists(at: durationPath)
    removeFileIfExists(at: acceleratePath)
    removeFileIfExists(at: resizePath)

    let converter = Converter4Video(path: finalPath)

    Task {
        do {
            try await converter.durationVideo(at: videoURL, outputPath: durationPath, targetDuration: 3)
            try await converter.accelerateVideo(at: durationPath, to: livePhotoDuration, outputPath: acceleratePath)
            try await converter.resizeVideo(at: acceleratePath, outputPath: resizePath, outputSize: livePhotoSize)

            print("### resize Success")
            let image = try await generateCGImage(finalPath: finalPath)

            await generateLivePhoto(
                image: image,
                documentPath: documentPath,
                assetIdentifier: assetIdentifier,
                metaURL: metaURL,
                converter: converter,
                complete: complete
            )
        } catch {
            print("Video conversion error: \(error)")
            complete(false, error.localizedDescription)
            return
        }
    }
}


  


• libav converted audio file distorted

  23 juillet 2015, par C0dR

  I am trying to implement a file converter using libav. Currently I am testing just the audio convertion (for example aac input and mp3 output). I am using the code from this question Conversion from mp3 to aac/mp4 container (FFmpeg/c++) but the resulting output file sounds corrupted (too slow, noisy, distorted).

  
  This is the result from converting AAC to mp3. AAC input format is AV_SAMPLE_FMT_FLTP and mp3 output format is AV_SAMPLE_FMT_S16P. It looks like part of the one channel is inverted on the other channel ?

  I am using avresample to convert the audio data. I just cant find out what is wrong, i already looked through the examples but as i can see i am doing it just like in the examples.
  Here is my converter class :

  http://pastebin.com/c6hvrRaM (.h)

  http://pastebin.com/u6iAPHZ9 (.cpp)

  I know this is pretty much but I am desperated...

• Playing encrypted m4a on Android

  20 novembre 2013, par Fixee

  I'm pulling down encrypted music, decrypting on-the-fly to m4a plaintext buffer and want to then play this music on Android (4.x). It appears the options are bleak :

  1. Write the buffer to disk and use MediaPlayer() with a FileDescriptor
  2. Write the buffer to disk and use a proxy like nano to serve MediaPlayer() via a URI
  3. Decode the buffer to PCM and use AudioTrack to play it

  Options 1 and 2 require writing plaintext to SD, which isn't acceptable. Option 3 requires decoding in software (with, eg, ffmpeg) which seems ridiculous : if there are hardware decoders on the device we can't use them. And if there is a software decoder, we can't access it and put yet another decoder on the device (ffmpeg's).

  Note that using OpenSL doesn't help at all : you still cannot play m4a's from a buffer. Is there another way ?