/// +=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
/// <summary>
/// Displays the video formats for the currently selected video device. This
/// is more complicated than it looks. We have to open the video source, convert
/// that to a Media Source and then interrogate the that source to find a list
/// of video formats.
///
/// NOTE: this function will throw exceptions - caller must trap them
/// </summary>
/// <history>
/// 01 Nov 18 Cynic - Started
/// </history>
private void DisplayVideoFormatsForCurrentCaptureDevice()
{
IMFPresentationDescriptor sourcePresentationDescriptor = null;
int sourceStreamCount = 0;
bool streamIsSelected = false;
IMFStreamDescriptor videoStreamDescriptor = null;
IMFMediaTypeHandler typeHandler = null;
int mediaTypeCount = 0;
List <TantaMFVideoFormatContainer> formatList = new List <TantaMFVideoFormatContainer>();
HResult hr;
IMFMediaSource mediaSource = null;
try
{
// clear what we have now
listViewSupportedFormats.Clear();
// reset this
listViewSupportedFormats.ListViewItemSorter = null;
// get the currently selected device
TantaMFDevice currentDevice = (TantaMFDevice)comboBoxCaptureDevices.SelectedItem;
if (currentDevice == null)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice currentDevice == null");
}
// use the device symbolic name to create the media source for the video device. Media sources are objects that generate media data.
// For example, the data might come from a video file, a network stream, or a hardware device, such as a camera. Each
// media source contains one or more streams, and each stream delivers data of one type, such as audio or video.
mediaSource = TantaWMFUtils.GetMediaSourceFromTantaDevice(currentDevice);
if (mediaSource == null)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to mediaSource == null");
}
// A presentation is a set of related media streams that share a common presentation time.
// we don't need that functionality in this app but we do need to presentation descriptor
// to find out the stream descriptors, these will give us the media types on offer
hr = mediaSource.CreatePresentationDescriptor(out sourcePresentationDescriptor);
if (hr != HResult.S_OK)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to mediaSource.CreatePresentationDescriptor failed. Err=" + hr.ToString());
}
if (sourcePresentationDescriptor == null)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to mediaSource.CreatePresentationDescriptor failed. sourcePresentationDescriptor == null");
}
// Now we get the number of stream descriptors in the presentation.
// A presentation descriptor contains a list of one or more
// stream descriptors.
hr = sourcePresentationDescriptor.GetStreamDescriptorCount(out sourceStreamCount);
if (hr != HResult.S_OK)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to sourcePresentationDescriptor.GetStreamDescriptorCount failed. Err=" + hr.ToString());
}
if (sourceStreamCount == 0)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to sourcePresentationDescriptor.GetStreamDescriptorCount failed. sourceStreamCount == 0");
}
// look for the video stream
for (int i = 0; i < sourceStreamCount; i++)
{
// we require the major type to be video
Guid guidMajorType = TantaWMFUtils.GetMajorMediaTypeFromPresentationDescriptor(sourcePresentationDescriptor, i);
if (guidMajorType != MFMediaType.Video)
{
continue;
}
// we also require the stream to be enabled
hr = sourcePresentationDescriptor.GetStreamDescriptorByIndex(i, out streamIsSelected, out videoStreamDescriptor);
if (hr != HResult.S_OK)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to sourcePresentationDescriptor.GetStreamDescriptorByIndex(v) failed. Err=" + hr.ToString());
}
if (videoStreamDescriptor == null)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to sourcePresentationDescriptor.GetStreamDescriptorByIndex(v) failed. videoStreamDescriptor == null");
}
// if the stream is not selected (enabled) look for the next
if (streamIsSelected == false)
{
Marshal.ReleaseComObject(videoStreamDescriptor);
videoStreamDescriptor = null;
continue;
}
// Get the media type handler for the stream. IMFMediaTypeHandler
// interface is a standard way of looking at the media types on an stream
hr = videoStreamDescriptor.GetMediaTypeHandler(out typeHandler);
if (hr != HResult.S_OK)
{
throw new Exception("call to videoStreamDescriptor.GetMediaTypeHandler failed. Err=" + hr.ToString());
}
if (typeHandler == null)
{
throw new Exception("call to videoStreamDescriptor.GetMediaTypeHandler failed. typeHandler == null");
}
// Now we get the number of media types in the stream descriptor.
hr = typeHandler.GetMediaTypeCount(out mediaTypeCount);
if (hr != HResult.S_OK)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to typeHandler.GetMediaTypeCount failed. Err=" + hr.ToString());
}
if (mediaTypeCount == 0)
{
throw new Exception("DisplayVideoFormatsForCurrentCaptureDevice call to typeHandler.GetMediaTypeCount failed. mediaTypeCount == 0");
}
// now loop through each media type
for (int mediaTypeId = 0; mediaTypeId < mediaTypeCount; mediaTypeId++)
{
// Now we have the handler, get the media type.
IMFMediaType workingMediaType = null;
hr = typeHandler.GetMediaTypeByIndex(mediaTypeId, out workingMediaType);
if (hr != HResult.S_OK)
{
throw new Exception("GetMediaTypeFromStreamDescriptorById call to typeHandler.GetMediaTypeByIndex failed. Err=" + hr.ToString());
}
if (workingMediaType == null)
{
throw new Exception("GetMediaTypeFromStreamDescriptorById call to typeHandler.GetMediaTypeByIndex failed. workingMediaType == null");
}
TantaMFVideoFormatContainer tmpContainer = TantaMediaTypeInfo.GetVideoFormatContainerFromMediaTypeObject(workingMediaType, currentDevice);
if (tmpContainer == null)
{
// we failed
throw new Exception("GetSupportedVideoFormatsFromSourceReaderInFormatContainers failed on call to GetVideoFormatContainerFromMediaTypeObject");
}
// now add it
formatList.Add(tmpContainer);
Marshal.ReleaseComObject(workingMediaType);
workingMediaType = null;
}
// NOTE: we only do the first enabled video stream we find.
// it is possible to have more but our control
// cannot cope with that
break;
}
// now display the formats
foreach (TantaMFVideoFormatContainer videoFormat in formatList)
{
ListViewItem lvi = new ListViewItem(new[] { videoFormat.SubTypeAsString, videoFormat.FrameSizeAsString, videoFormat.FrameRateAsString, videoFormat.FrameRateMaxAsString, videoFormat.AllAttributes });
lvi.Tag = videoFormat;
listViewSupportedFormats.Items.Add(lvi);
}
listViewSupportedFormats.Columns.Add("Type", 70);
listViewSupportedFormats.Columns.Add("FrameSize WxH", 100);
listViewSupportedFormats.Columns.Add("FrameRate f/s", 100);
listViewSupportedFormats.Columns.Add("FrameRateMax f/s", 100);
listViewSupportedFormats.Columns.Add("All Attributes", 2500);
}
finally
{
// close and release
if (mediaSource != null)
{
Marshal.ReleaseComObject(mediaSource);
mediaSource = null;
}
if (sourcePresentationDescriptor != null)
{
Marshal.ReleaseComObject(sourcePresentationDescriptor);
sourcePresentationDescriptor = null;
}
if (videoStreamDescriptor != null)
{
Marshal.ReleaseComObject(videoStreamDescriptor);
videoStreamDescriptor = null;
}
if (typeHandler != null)
{
Marshal.ReleaseComObject(typeHandler);
typeHandler = null;
}
}
}
