Is decoder automaticly added between two filter?

0
votes

I have created a c++ dll where it shows camera live streaming at panel handle with DirectShow API. My Camera is Logitech c920 Webcam. My camera offers H264 codec on the 3rd output pin.

When I use graphEdit, if I connect the Logitech Webcam 3rd output Pin to Video Mixing Render 9 1st input pin, it automaticly adds the DTV-DVD microsoft decoder between the connection like this :

Logitech HD Pro Webcam C920 [Capturer] => [VMR Input0] Video Mixing Renderer 9

(When connected become)

Logitech HD Pro Webcam C920 [Capturer] => [video Input1] Microsoft DTV-DVD Video Decoder [video Output 1] => [VMR Input0] Video Mixing Renderer 9

The quality is very nice and I have a fast video streaming rates on the active movie window.

This is where it's getting incorrect. In my code, I have directly connected the 3rd pin of capture source to vmr7 input pin (without adding dt-dvd decoder). I have also set the video settings as 1600x896 and H264 Mediatype with IAMStreamConfig.

I readed on msdn (if i have understand correctly) that directshow will automaticly put the necessary filter between two connected pins. It's working but the video quality is terrible.It looks like theres lot pixels mixed or corrupted. I also don't have any evidence that the filter as been added. Is it because i haven't programmaticaly put the decoder between them? And if it could be, how do I add this filter?

Thanks in advance and sorry for the english.

1
c++winapivideowebcamdirectshow

1 Answers

1
votes

The problem is here:

if I connect the Logitech Webcam 3rd output Pin to Video Mixing Render 9

versus

I have directly connected the 3rd pin of capture source to vmr7 input pin

VMR-9 vs. VMR-7. The former is backed by Direct3D surfaces, with frames scaled smoothly by hardware. The latter, on the opposite, uses DirectDraw surfaces with scaling unavailable since Windows Vista, and the picture quality is terrible.

Use EVR as video renderer (or VMR-9) to get best picture quality.