VirtualCapture with mkv format

[kenavolic]

Hi,

I've a compiled version of PlusToolkit and IGSIO that enables video streaming and VP9.

I run the server with the following configuration file:

<PlusConfiguration version="2.0" PlusRevision="Plus-2.9.0.098f54b7 - Win32">
<DataCollection StartupDelaySec="1.0">
    <DeviceSet Name="PlusServer: Compressed video using Media Foundation video capture device" Description="Broadcasting video frames compressed using VP9" />
    <Device Id="VideoDevice" Type="MmfVideo" FrameSize="640 480" VideoFormat="YUY2" CaptureDeviceId="0">
      <DataSources>
        <DataSource Type="Video" Id="Video" PortUsImageOrientation="MN" ImageType="RGB_COLOR" />
      </DataSources>
      <OutputChannels>
        <OutputChannel Id="VideoStream" VideoDataSourceId="Video" />
      </OutputChannels>
    </Device>
    <Device Id="CaptureDevice" Type="VirtualCapture" BaseFilename="RecordingTest.mkv" EnableCapturingOnStart="TRUE">
      <InputChannels>
        <InputChannel Id="VideoStream" />
      </InputChannels>
    </Device>
  </DataCollection>
  <PlusOpenIGTLinkServer MaxNumberOfIgtlMessagesToSend="1" MaxTimeSpentWithProcessingMs="50" ListeningPort="18944" SendValidTransformsOnly="true" OutputChannelId="VideoStream">
    <DefaultClientInfo>
      <MessageTypes>
        <Message Type="VIDEO" />
      </MessageTypes>
      <VideoNames>
        <Video Name="Video" EmbeddedTransformToFrame="Video">
          <Encoding FourCC="VP90" Lossless="FALSE" Speed="8" DeadlineMode="REALTIME" RateControl="Q" />
        </Video>
      </VideoNames>
    </DefaultClientInfo>
  </PlusOpenIGTLinkServer>
</PlusConfiguration>

I am unable to read the mkv with a regular reader because:

• Media player output: "the playback of this movie requires a video/x-unknown decoder"
• VLC player log: "the code id is not set"

Here is the output of media info:

General
Complete name                            : /media/cgarraud/SanDisk/TRANSWINCHU/RecordingTest_20231020_145222.mkv
Format                                   : Matroska
Format version                           : Version 4
File size                                : 14.1 MiB
Duration                                 : 14 s 960 ms
Overall bit rate                         : 7 886 kb/s
Writing application                      : libwebm-0.3.1.0
Writing library                          : libwebm-0.3.1.0

Video
ID                                       : 1
Duration                                 : 14 s 911 ms
Bit rate                                 : 7 729 kb/s
Width                                    : 640 pixels
Height                                   : 480 pixels
Display aspect ratio                     : 4:3
Frame rate mode                          : Constant
Frame rate                               : 1.006 FPS
Bits/(Pixel*Frame)                       : 25.010
Stream size                              : 13.7 MiB (98%)
Title                                    : Video
Default                                  : Yes
Forced                                   : No

Text
ID                                       : 2
Format                                   : UTF-8
Codec ID                                 : S_TEXT/UTF8
Codec ID/Info                            : UTF-8 Plain Text
Title                                    : Timestamp
Default                                  : Yes
Forced                                   : No

I see there is no setting for the encoding of the VideoCapture. Do we have to set it with MmfVideo VideoFormat or OpenCVVideo FourCC?

Thanks for your help!