Android MediaPlayer can't SetDataSource()

Question

I'm trying to set the data source for a media player, but it keeps throwing this exception.

java.io.IOException: setDataSourceFD failed

Where am I going wrong?

java.io.IOException: setDataSourceFD failed.: status=0x80000000
    at android.media.MediaPlayer._setDataSource(Native Method)
    at android.media.MediaPlayer.setDataSource(MediaPlayer.java:1025)
02-05 11:11:37.664 I/mono-stdout(19741):   at Android.Runtime.JNIEnv.CallVoidMethod (IntPtr jobject, IntPtr jmethod, Android.Runtime.JValue[] parms) [0x00063] in /Users/builder/data/lanes/monodroid-mlion-monodroid-4.10.2-branch/4b53fbd0/source/monodroid/src/Mono.Android/src/Runtime/JNIEnv.g.cs:507 
    at futurestate.audiobook.droid.ui.views.home.HomeView.n_onCreate(Native Method)
    at futurestate.audiobook.droid.ui.views.home.HomeView.onCreate(HomeView.java:31)
    at android.app.Activity.performCreate(Activity.java:5231)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)
    at android.app.ActivityThread.access$800(ActivityThread.java:135)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1196)
    at android.os.Handler.dispatchMessage(Handler.java:102)
    at android.os.Looper.loop(Looper.java:136)
    at android.app.ActivityThread.main(ActivityThread.java:5017)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:515)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
    at

Here's my code. The Player.SetDataSource() is the failing line.

if (Player == null)
{
    try
    {
        var expansionFile = ApkExpansionSupport.GetApkExpansionZipFile(Application.Context, 1, 0);
        var entry = expansionFile.GetEntry(FileName);

        // I can see all entries with the line below. 
        // Therefore the above code can reach into the obb and see the contents.
        // var entries = expansionFile.GetAllEntries();

        var pfd = ParcelFileDescriptor.Open(new File(entry.ZipFileName), ParcelFileMode.ReadOnly);
        var afd = new AssetFileDescriptor(pfd, entry.FileOffset, entry.FileSize);
        var fd = afd.FileDescriptor;

        Player = new MediaPlayer();
        Player.Reset();
        Player.SetWakeMode(Application.Context, WakeLockFlags.Partial);
        Player.Looping = false;

        Player.SetDataSource(fd, afd.StartOffset, afd.Length);
        Player.Prepare();
    }
    catch (Exception ex)
    {
        Console.Out.WriteLine(ex.Message);
        Console.Out.WriteLine(ex.Source);
        Console.Out.WriteLine(ex.InnerException);
        Console.Out.WriteLine(ex.StackTrace);
    }

    SeekTo(_startingPointMsec);
    DurationMsec = (Player.Duration);
}

Answer 1

Well, I suppose I don't know if I should feel stupid or plain mad. The whole problem with my approach was due to the fact that Microsoft's idea of "NoCompression" is a little askew.

note: the code in the question works and is correct"

The problem comes out of the fact that I was using Powershell to automate the creation of my .obb file. The script was leveraging System.IO.Compression, and when I set the System.IO.Compression.CompressionLevel to NoCompression, it still mangled my obb file.

I fired up my console and installed 7zip (ps: chocolatey rocks.)

> cinst 7zip

and recreated the obb file using the Store mode, and everything worked.

Now that this is figured out, here's our PowerShell build script

function Invoke-CreateExpansionApk
{
    param(
        [Parameter(Position=0, HelpMessage="Type of apk to create: main|patch")]
        [ValidateSet('main','patch')]
        [System.String]$Type = 'main',
        [Parameter(Position=1, Mandatory=$true, HelpMessage="Must be the same name as your Play Store App")]
        [System.String]$ApkName,

        [Parameter(Position=2, Mandatory=$true)]
        [System.String]$SourceDir,
        [Parameter(Position=3, Mandatory=$true)]
        [System.String]$OutputDir,
        [Parameter(Position=4)]
        [System.Double]$Version = 1
    )
    $PRIVATE:bundleVersion = $Version

    $PRIVATE:fileName = "$OutputDir\$Type.$bundleVersion.$ApkName.obb"

    $pwd = Get-ModuleDirectory
    set-alias sz $pwd\7za.exe
    sz a -tzip $fileName $SourceDir -mx0
}