Support for .aax files through ffmpeg

[JKamsker]

Using the ffmpeg package, it always returns "[aax] activation_bytes option is missing!" which indicates, that the "-activation_bytes" option is missing.

With my current state of knowledge, i don't know how to implement this. I hope you can show me a workaround or even provide a fix :)

Sample ffmpeg commandline: ffmpeg -activation_bytes abababab -i .\MyAudioFile.aax -vn -c:a copy MyAudioFile.m4b

Edit: I guess the last argument in https://github.com/filoe/cscore/blob/13bbebb4f0a8c3e12fc54a01c3485098bf13ba9c/CSCore.Ffmpeg/FfmpegCalls.cs#L173 should not be null to pass the extra argument.

[filoe]

I would have guessed the same. Could you maybe try that out whether that works or at least upload a testfile?

[JKamsker]

@filoe Have sent a mail with the files to (hopefully) your personal @fortix.io mail address. Could you please confirm that you got it? :D

If i could create and handle a native struct, i would have formulated my issue differently. But i can't, so i desperately begging you for help instead 😅

Edit: I've played around with it a bit and im quite sure he eats the struct i feed into the method but somehow it also results in a AccessViolationException :(

     internal static unsafe void AvformatOpenInput(AVFormatContext** formatContext, AvioContext avioContext)
{
    var key = Encoding.ASCII.GetBytes("activation_bytes").Select(x => (sbyte)x).ToArray();
    var value = Encoding.ASCII.GetBytes("abababab").Select(x => (sbyte)x).ToArray();

    fixed (sbyte* f_key = key)
    fixed (sbyte* f_value = value)
    {
        var elem = new[]
        {
          new AVDictionaryEntry { key = f_key, value = f_value }
        };

        fixed (AVDictionaryEntry* ee = elem)
        {
            AVDictionary dict = new AVDictionary { count = 1, elems = ee };

            AVDictionary* px = &dict;
            AVDictionary** px1 = &px;

            (*formatContext)->pb = (AVIOContext*)avioContext.ContextPtr;
            int result = ffmpeg.avformat_open_input(formatContext, "DUMMY-FILENAME", null, px1);//px1
            FfmpegException.Try(result, "avformat_open_input");
        }
    }
}

[JKamsker]

@filoe I've found some public aax files here: https://gitlab.com/vesselin.bontchev/audible-samples/tree/master

[JKamsker]

@filoe Have you tryed reproducing the error already?