CODEWITHSUNDEEP
c#audiomp3winmm
Medic3000
Medic3000

Reputation: 786

C#4.0 Issues playing .mp3 files over 192kbps using winmm.dll

MCIERR_INTERNALI am trying to make a simple Media player inside an app, but I've noticed that my code WILL NOT play music unless the file is a low bitrate around 192kbps or less. The issue is that most of my music is around 260-320kbps.

Here's my code, if there's something I can do to up the 'available' bitrate options let me know, otherwise I'll need a new DLL suggestion please!

class MusicPlayer
{
    [DllImport("winmm.dll")]
    private static extern long mciSendString(string lpstrCommand, StringBuilder lpstrReturnString, int uReturnLength, int hwndCallback);

    private static void checkMCIResult(long code)
    {
        int err = (int)(code & 0xffffffff);
        if (err != 0)
        {
            throw new Exception(string.Format("MCI error {0}", err));
        }
    }

    public void open(string file)
    {
        string command = "open \"" + file + "\" type MPEGVideo alias MyMp3";
        checkMCIResult(mciSendString(command, null, 0, 0));
    }

    public void play()
    {
        string command = "play MyMp3";
        mciSendString(command, null, 0, 0);
    }
    public void pause()
    {
        string command = "stop MyMp3";
        mciSendString(command, null, 0, 0);
    }
}

**EDIT: -Winform application

-using Windows 7 sp1

-Using Visulal Studio 2013 community edition

-From error catching I now see the error number is 289, -256 = 22: MCIERR_INTERNAL, not sure what that's all about

Upvotes: 4

Views: 1776

Answers (3)

Roman Ryltsov
Roman Ryltsov

Reputation: 69706

A typical problem with Windows API playing or not playing specific MP3 files is the following. One of the standard MP3 reading/parsing components has a [presumably?, I am under impression 16KB is in question] fixed size buffer to read initially, then skip tags and get to the real bitstream. With a lot of tags, the parser is unable to read the data and rejects the file as non-playable.

When played through DirectShow (for C# code, this would typically be playback through DirectShow.NET open source library), it is suggested to use another stock Windows component capable to read MP3 files, which is free from tag problem: Windows Media ASF Reader filter.

See related:

Even though it's a long standing issue, Microsoft years ago decided to not update standard MPEG-1 stream splitter and the problem basically exists in all Windows versions.

Upvotes: 0

Medic3000
Medic3000

Reputation: 786

Ok, so I figured this out (thanks to @Hans Passant), the error code I was recieving was 277, Turns out there are problems with MCI and mp3's which had a large ID3(v2.x) tag - Album art, lyrics etc.

Coincidentally the 2 files causing me the trouble had album art, and completely filled out ID3 data (including Lyrics). So I'll be switching over to some other audio library for my needs

Upvotes: 1

Hans Passant
Hans Passant

Reputation: 942040

This is not an inherent limitation in Windows, problems like these are environmental. A basic check-list:

  • Try this with a known-good MP3 file. That test file is encoded at 320 kbps. This helps eliminate a specific problem with your files, like a wonky DRM scheme that only permits playback on an approved player.
  • Make sure you run this code on an STA thread, the kind provided by a Winforms or WPF app. Not a console mode app, it requires the kind of code you find in this post.
  • Beware of having non-standard ACM drivers installed. There is a lot of junk out there, always treat "codec packs" with strong distrust. Review the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Drivers32 registry key, that's where ACM drivers are registered.
  • And last but certainly not least, you are blind as a bat as long as you are ignoring the return value of mciSendString(). When it fails, it produces an error code that tells you the reason.

A simple implementation of an error checker method:

    private static void checkMCIResult(long code) {
        int err = (int)(code & 0xffffffff);
        if (err != 0) {
            throw new Exception(string.Format("MCI error {0}", err));
        }
    }

Usage:

    public static void open(string file) {
        string command = "open \"" + file + "\" type MPEGVideo alias MyMp3";
        checkMCIResult(mciSendString(command, null, 0, 0));
    }

There are a lot of possible MCI errors, you'll find them listed in MMSystem.h file in the Windows SDK "include" directory on your machine. Like C:\Program Files (x86)\Microsoft SDKs\Windows\v7.1A\Include\MMSystem.h. Start at MCIERR_INVALID_DEVICE_ID, subtract 256 from the error code. Always mention your Windows and VS version btw.

Upvotes: 6

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