Save any DPX with PAL Resolutions

-(void)saveAsPAL:(id)sender
{
    NSSavePanel* dlg = [NSSavePanel savePanel];
    [dlg setCanCreateDirectories:TRUE];
    [dlg setAllowedFileTypes:[NSArray arrayWithObject:@"dpx"]];
    [dlg setShowsHiddenFiles:NO];
    [dlg setTitle:@"Save As DPX File"];
    if ([dlg runModal] != NSOKButton)
        return;

    /*
     * First we should create CGBitmapContext as a layer to draw scaled bitmap,
     * and then take the result as bitmap data,
     * transfer it into 10-Bit RGB format.
     */
    CGColorSpaceRef rgbColorspace = CGColorSpaceCreateDeviceRGB();
    CGContextRef palBitmap = CGBitmapContextCreate(NULL,
                    720, 576,
                    8, 720*4,
                    rgbColorspace,
                    kCGImageAlphaPremultipliedFirst|kCGBitmapByteOrder32Little);
    CFRelease(rgbColorspace);
    CGFloat scaledHeight = (720*[image size].height)/[image size].width;
    CGFloat yOffset = 0;
    if (scaledHeight < 576)
        yOffset = (576-scaledHeight)/2;

    CGContextSetFillColorWithColor(palBitmap, CGColorCreateGenericRGB(0, 0, 0, 1));
    CGContextFillRect(palBitmap, CGRectMake(0, 0, 720, 576));
    CGContextDrawImage(palBitmap,
            CGRectMake(0, yOffset, 720, scaledHeight),
            [image CGImage]);
    uint32_t* pImgData = (uint32_t*)CGBitmapContextGetData(palBitmap);

    size_t iLen = sizeof(DPXHeader) + sizeof(DPXImageHeader) +
        sizeof(DPXImageOrientation) + sizeof(DPXFilmHeader) +
        sizeof(DPXTVHeader) + 32;

    int bmSize = 720*576*4;
    iLen += bmSize;

    uint8_t* pData = (uint8_t*)malloc(iLen);
    memset(pData, 0xFF, iLen);

    DPXHeader* hdr = (DPXHeader*)pData;
    DPXImageHeader* imgHdr = (DPXImageHeader*)(hdr+1);
    DPXImageOrientation* orient = (DPXImageOrientation*)(imgHdr+1);
    DPXFilmHeader* filmHdr = (DPXFilmHeader*)(orient+1);
    DPXTVHeader* tvHdr = (DPXTVHeader*)(filmHdr+1);
    hdr->magic = SDPX_MAGIC;
    hdr->image_offset = iLen - bmSize;
    strcpy((char*)hdr->version, "v2.0");
    hdr->version[4] = 0;
    hdr->file_size = iLen;
    hdr->ditto_key = 0;
    hdr->generic_hdr_size = sizeof(DPXHeader)+sizeof(DPXImageHeader)+sizeof(DPXImageOrientation);
    hdr->industry_hdr_size = sizeof(DPXFilmHeader) + sizeof(DPXTVHeader);
    hdr->user_data_size = 32;
    hdr->encrypt_key = 0;
    strcpy((char*)hdr->file_name,
           [[[[dlg URL] path] lastPathComponent] UTF8String]);

    NSDate* strNow = [NSDate date];
    NSCalendar* calendar = [NSCalendar currentCalendar];
    NSDateComponents* components =
        [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|
            NSDayCalendarUnit|NSHourCalendarUnit|
            NSMinuteCalendarUnit|NSSecondCalendarUnit
                fromDate:strNow];
    NSString* strTest = [NSString stringWithFormat:@"%i:%i:%i:%i:%i:%i",
                         [components year],
                         [components month],
                         [components day],
                         [components hour],
                         [components minute],
                         [components second]];
    strcpy((char*)hdr->creation_date, [strTest UTF8String]);
    strcpy((char*)hdr->creator, "Adi");
    strcpy((char*)hdr->project, "Test PAL");
    strcpy((char*)hdr->copyright, "2012, FX. J. Adi Lima");
    imgHdr->orientation = 0;
    imgHdr->number_of_elements = 1;
    imgHdr->img_width = 720;
    imgHdr->img_height = 576;

    imgHdr->img_element[0].data_sign = 0;
    imgHdr->img_element[0].data_offset = hdr->image_offset;
    imgHdr->img_element[0].eo_image_padding = 0;
    imgHdr->img_element[0].eol_padding = 0;
    imgHdr->img_element[0].bit_size = 10;
    strcpy((char*)imgHdr->img_element[0].description, "TESTING");
    imgHdr->img_element[0].descriptor = 50;
    imgHdr->img_element[0].packing = 2; // 10 Bit DPX Method B
    imgHdr->img_element[0].encoding = 0;
    strcpy((char*)filmHdr->format, "PAL Method B");
    filmHdr->framerate = 25;
    filmHdr->shutter_angle = 180.0f;
    //strcpy((char*)tvHdr->timecode, "00:00:00:01");
    tvHdr->timecode.value = 1;

    int nCount = 720*576;
    uint32_t* pDest = (uint32_t*)(pData+hdr->image_offset);
    uint32_t* pSrc = pImgData;
    int i;
    uint32_t nVal = 0;
    uint32_t rgbVal;
    for (i = 0; i < nCount; i++)
    {
        nVal = *pSrc++;
        // Alpha Premultiplied First means ARGB (same as BGRA_Interleaved)
        // Has to be saved the same order, but minus alpha.
        rgbVal = (VALUE_8_TO_10(nVal)) | (VALUE_8_TO_10(nVal>>8)<<10) |
            (VALUE_8_TO_10(nVal>>16)<<20);
        *pDest++ = rgbVal;
    }
    NSData* pRes = [[NSData alloc] initWithBytes:pData length:iLen];
    [pRes writeToURL:[dlg URL] atomically:YES];
    [pRes release];

    NSRunAlertPanel(@"Report",
            [NSString stringWithFormat:@"Saving %@ completed.\n", [[dlg URL] path]],
            @"OK", NULL, NULL);

    CGContextRelease(palBitmap);
    free(pData);
}