Test observations

[sipsorcery]

An observation note rather than an issue (27 Nov 2021):

• Tested with the WebRTCReceiver example.
  • Initial 640x480 stream from Chrome to the Windows FOrms application is decoded with very low latency.
  • In one test latency grew very noticeably with a lag of multiple seconds.
  • In other tests latency stayed low.
  • The video decoding did fail, see screenshot, but this corresponded with console message about missinf RTP packets so is more likely a result of mssing input frames rather than a decoder bug. Signal did come back after a minute or two, when Chrome generated the next key frame.
  • No segfaults or memory leaks observed.
  • CPU and memory use very low.

• Same test but requested Chrome video resolution of 1024x768:
  • Chrome initially sends 640 x 360
    • No noticeable latency on decoder.
  • Chrome change resolution to 960x540
    • Noticeable 1 to 2s latency on decoder.
    • RTP missing packets log meessages.
    • AccessViolation exception on decoder

Fatal error. System.AccessViolationException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.
   at Vpx.Net.filter.filter_block2d_first_pass(Byte*, Int32*, UInt32, UInt32, UInt32, UInt32, Int16* ByRef)
   at Vpx.Net.filter.filter_block2d(Byte*, Byte*, UInt32, Int32, Int16*, Int16*)
   at Vpx.Net.filter.vp8_sixtap_predict4x4_c(Byte*, Int32, Int32, Int32, Byte*, Int32)
   at Vpx.Net.vp8_rtcd.vp8_sixtap_predict4x4_c(Byte*, Int32, Int32, Int32, Byte*, Int32)
   at Vpx.Net.vp8_rtcd.vp8_sixtap_predict4x4(Byte*, Int32, Int32, Int32, Byte*, Int32)
   at Vpx.Net.reconinter.build_inter_predictors_b(Vpx.Net.BLOCKD, Byte*, Int32, Byte*, Int32, Vpx.Net.vp8_subpix_fn_t)
   at Vpx.Net.reconinter.build_inter4x4_predictors_mb(Vpx.Net.MACROBLOCKD ByRef)
   at Vpx.Net.reconinter.vp8_build_inter_predictors_mb(Vpx.Net.MACROBLOCKD ByRef)
   at Vpx.Net.decodeframe.decode_macroblock(Vpx.Net.VP8D_COMP, Vpx.Net.MACROBLOCKD, UInt32)
   at Vpx.Net.decodeframe.decode_mb_rows(Vpx.Net.VP8D_COMP)
   at Vpx.Net.decodeframe.vp8_decode_frame(Vpx.Net.VP8D_COMP)
   at Vpx.Net.onyxd.vp8dx_receive_compressed_data(Vpx.Net.VP8D_COMP, Int64)
   at Vpx.Net.vp8_dx.vp8_decode(Vpx.Net.vpx_codec_alg_priv_t, Byte*, UInt32, IntPtr, Int64)
   at Vpx.Net.vpx_decoder.vpx_codec_decode(Vpx.Net.vpx_codec_ctx_t, Byte*, UInt32, IntPtr, Int64)
   at Vpx.Net.VP8Codec.DecodeVideo(Byte[], SIPSorceryMedia.Abstractions.VideoPixelFormatsEnum, SIPSorceryMedia.Abstractions.VideoCodecsEnum)
   at Vpx.Net.Vp8NetVideoEncoderEndPoint.GotVideoFrame(System.Net.IPEndPoint, UInt32, Byte[], SIPSorceryMedia.Abstractions.VideoFormat)
   at SIPSorcery.Net.RTPSession.OnReceive(Int32, System.Net.IPEndPoint, Byte[])
   at SIPSorcery.Net.RTCPeerConnection.OnRTPDataReceived(Int32, System.Net.IPEndPoint, Byte[])
   at SIPSorcery.Net.RtpIceChannel.OnRTPPacketReceived(SIPSorcery.Net.UdpReceiver, Int32, System.Net.IPEndPoint, Byte[])
   at SIPSorcery.Net.UdpReceiver.EndReceiveFrom(System.IAsyncResult)
   at System.Net.LazyAsyncResult.Complete(IntPtr)
   at System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
   at System.Net.ContextAwareResult.Complete(IntPtr)
   at System.Net.Sockets.BaseOverlappedAsyncResult.CompletionPortCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)
   at System.Threading._IOCompletionCallback.PerformIOCompletionCallback(UInt32, UInt32, System.Threading.NativeOverlapped*)