如何从SoftwareBitmap获取字节数组

Question

嗨,我需要有关如何从SoftwareBitmapC#UWP中获取字节数组的帮助,以便我可以通过TCP套接字发送它.

我还可以访问"VideoFrame previewFrame"对象,这是我从中获取的对象SoftwareBitmap.

我在网上看到了类似下面的内容,但是UWP并不支持wb.SaveJpeg(...).除非我错过了什么？

MemoryStream ms = new MemoryStream();
WriteableBitmap wb = new WriteableBitmap(myimage);
wb.SaveJpeg(ms, myimage.PixelWidth, myimage.PixelHeight, 0, 100);
byte [] imageBytes = ms.ToArray();

任何帮助,或正确方向的指示,将不胜感激.

谢谢,安迪

Answer 1

当然，您可以从中访问编码 byte[]数组SoftwareBitmap。

参见此示例，提取jpeg编码byte[]：

// includes BitmapEncoder, which defines some static encoder IDs
using Windows.Graphics.Imaging;


private async void PlayWithData(SoftwareBitmap softwareBitmap)
{
    // get encoded jpeg bytes
    var data = await EncodedBytes(softwareBitmap, BitmapEncoder.JpegEncoderId);

    // todo: save the bytes to a DB, etc
}

private async Task<byte[]> EncodedBytes(SoftwareBitmap soft, Guid encoderId)
{
    byte[] array = null;

    // First: Use an encoder to copy from SoftwareBitmap to an in-mem stream (FlushAsync)
    // Next:  Use ReadAsync on the in-mem stream to get byte[] array

    using (var ms = new InMemoryRandomAccessStream())
    {
        BitmapEncoder encoder = await BitmapEncoder.CreateAsync(encoderId, ms);
        encoder.SetSoftwareBitmap(soft);

        try
        {
            await encoder.FlushAsync();
        }
        catch ( Exception ex ){ return new byte[0]; }

        array = new byte[ms.Size];
        await ms.ReadAsync(array.AsBuffer(), (uint)ms.Size, InputStreamOptions.None);
    }
    return array;
}

Answer 2

到目前为止我知道你不能这样做.但您可以使用SoftwareBitmap.看例子:https://msdn.microsoft.com/en-us/library/windows/apps/mt244351.aspx(SoftwareBitmap是SoftwareBitmapSource的私人领域..通过反射.刚读它......也许这是完全错误的建议)

private async void SaveSoftwareBitmapToFile(SoftwareBitmap softwareBitmap, StorageFile outputFile)
{
    using (IRandomAccessStream stream = await outputFile.OpenAsync(FileAccessMode.ReadWrite))
    {
        // Create an encoder with the desired format
        BitmapEncoder encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, stream);

        // Set the software bitmap
        encoder.SetSoftwareBitmap(softwareBitmap);

        // Set additional encoding parameters, if needed
        encoder.BitmapTransform.ScaledWidth = 320;
        encoder.BitmapTransform.ScaledHeight = 240;
        encoder.BitmapTransform.Rotation = Windows.Graphics.Imaging.BitmapRotation.Clockwise90Degrees;
        encoder.BitmapTransform.InterpolationMode = BitmapInterpolationMode.Fant;
        encoder.IsThumbnailGenerated = true;

        try
        {
            await encoder.FlushAsync();
        }
        catch (Exception err)
        {
            switch (err.HResult)
            {
                case unchecked((int)0x88982F81): //WINCODEC_ERR_UNSUPPORTEDOPERATION
                                                 // If the encoder does not support writing a thumbnail, then try again
                                                 // but disable thumbnail generation.
                    encoder.IsThumbnailGenerated = false;
                    break;
                default:
                    throw;
            }
        }

        if (encoder.IsThumbnailGenerated == false)
        {
            await encoder.FlushAsync();
        }


    }
}

Answer 3

要从SoftwareBitmap获取字节数组,您可以使用"SoftwareBitmap.CopyToBuffer"

但是,首先你需要:

使用System.Runtime.InteropServices.WindowsRuntime;

因为方法AsBuffer()到byte []

...

StorageFile file = await StorageFile.GetFileFromPathAsync(ImageFilePath);
using (IRandomAccessStream fileStream = await File.OpenAsync(FileAccessMode.Read),
                                           memStream = new InMemoryRandomAccessStream())
  {
  // Open a Stream and decode a JPG image
  BitmapDecoder decoder = await BitmapDecoder.CreateAsync(fileStream);
  var softwareBitmap = await decoder.GetSoftwareBitmapAsync();

  byte [] imageBytes = new byte[4*decoder.PixelWidth*decoder.PixelHeight];
  softwareBitmap.CopyToBuffer(imageBytes.AsBuffer());
  //...  now you can use the imageBytes[]
}