Resizing Portrait Bitmap to Landscape Dimensions in Android

Question

I am trying to create a video from a set of images, those images might be of Portrait or Landscape. I want the final video to be of Landscape so I am re-sizing the portrait image to the dimensions of a landscape image. Obviously, the image quality is very poor and it gets stretched. I tried rotating the bitmap to landscape mode after re-scaling but not able to achieve what I require. All I want is a set of images with the same dimensions, and I have absolutely no problem if there is some black space on the either side of the portrait image while re-sizing.

What I have tried so far :

                        Bitmap bmp = BitmapFactory.decodeFile(created_folder + File.separator + "pic00" + (k + 1) + ".jpg");
                        Matrix matrix = new Matrix();
                        if (image_orientaion == 6) {
                            matrix.postRotate(90);
                        } else if (image_orientaion == 3) {
                            matrix.postRotate(180);
                        } else if (image_orientaion == 8) {
                            matrix.postRotate(270);
                        }

                        //bmp = Bitmap.createBitmap(bmp, 0, 0, dm.widthPixels, (dm.widthPixels * bmp.getHeight() / bmp.getWidth()), matrix, true);
                        Log.e("The Iriginal Heihgt and Width is ","Width " + bmp.getWidth() + " Height " + bmp.getHeight());
                        if (bmp.getWidth() < bmp.getHeight()) {
                            bmp = scaleBitmap(bmp,bmp.getWidth(),bmp.getHeight());
                            Log.e("The Height and Wiedth after scalimg is "," Width : " + bmp.getWidth() + "Height : " + bmp.getHeight());
                            bmp = Bitmap.createBitmap(bmp, 0, 0, bmp.getHeight(), bmp.getWidth(), matrix, true);
                        } else {
                            bmp = RescalingBitmap(bmp);
                            Log.e("The Height and Wiedth after scalimg is "," Width : " + bmp.getWidth() + "Height : " + bmp.getHeight());
                            bmp = Bitmap.createBitmap(bmp, 0, 0, bmp.getWidth(), bmp.getHeight(), matrix, true);
                        }


                        //  Log.e("The Bitmap height and width is ","Height is " + bmp.getHeight() + " Width is " + bmp.getWidth());
                        FileOutputStream fOut;
                        try {
                            fOut = new FileOutputStream(created_folder + File.separator + "pic00" + (k + 1) + ".jpg");
                            bmp.compress(Bitmap.CompressFormat.JPEG, 85, fOut);
                            fOut.flush();
                            fOut.close();
                            bmp.recycle();

                        } catch (FileNotFoundException e1) {
                            // TODO Auto-generated catch block
                            e1.printStackTrace();
                        } catch (IOException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                        }

 public static Bitmap scaleBitmap(Bitmap bitmap, int wantedWidth, int wantedHeight) {
        float originalWidth = bitmap.getWidth();
        float originalHeight = bitmap.getHeight();
        Bitmap output = Bitmap.createBitmap(wantedWidth, wantedHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(output);
        Matrix m = new Matrix();

        float scalex = wantedWidth/originalWidth;
        float scaley = wantedHeight/originalHeight;
        float xTranslation = 0.0f, yTranslation = (wantedHeight - originalHeight * scaley)/2.0f;

        m.postTranslate(xTranslation, yTranslation);
        m.preScale(scalex, scaley);
        // m.setScale((float) wantedWidth / bitmap.getWidth(), (float) wantedHeight / bitmap.getHeight());
        Paint paint = new Paint();
        paint.setFilterBitmap(true);
        canvas.drawBitmap(bitmap, m, paint);

        return output;
    }

Other alternatives :

1. I tried not to compress the bitmap but no use.
2. I tried to set the width and height of the bitmap according to screen size but didn't get a solid lead.
3. I have tried to re-assign the width and height of the portrait image so that their dimension will be of a dimension of a landscape image.

Any idea on how to re-scale the portrait image to that of a landscape or that of a landscape dimension but with the portrait image in the center with or without any black spaces on either side ? Any help or insights will be much appreciated !

P.S :

I am using these bitmap images to create a video so I AM NOT LOOKING TO FIT THIS IN A IMAGEVIEW. Just converting the portrait bitmap to a landscape one with the same dimension but not stretched is my aim.

EDIT :

According to the suggestion of Budius from comments section, I tried to use setRectToRect method as follows but that didn't bring me much change.

            Bitmap bmp = decodeFile(new File(created_folder + File.separator + "pic00" + (k + 1) + ".jpg"));
            Matrix matrix = new Matrix();
             float scale = 1024/bmp.getWidth();
            float xTranslation = 0.0f, yTranslation = (720 - bmp.getHeight() * scale)/2.0f;
            RectF drawableRect = new RectF(0, 0, bmp.getWidth()-100,
                    bmp.getHeight()-100);

            RectF viewRect = new RectF(0, 0, bmp.getWidth(),
                    bmp.getHeight());

                matrix.setRectToRect(drawableRect, viewRect, Matrix.ScaleToFit.CENTER);
                matrix.setRotate(90, bmp.getWidth(), bmp.getHeight());
                matrix.postTranslate(xTranslation, yTranslation);
                matrix.preScale(scale, scale);

Applying setRectToRect after setRotate and postTranslate doesn't rotate the image but shows the same image in portrait mode. I want all images to be in landscape mode, if I apply rotation then my resulting image is like this. I just dont want it to be stretched. I want that image to look like a normal landscape image or like this. Any help would be much appreciated.