title: Change video stream resolution in YoloV4 demo
body: <p>Here's what shows when loading the live stream demo for Yolov4:</p>
  
  <p>Webcam index: 2
  [ WARN:0] global ../modules/videoio/src/cap_gstreamer.cpp (935) open OpenCV | GStreamer warning: Cannot query video position: status=0, value=-1, duration=-1
  Video stream: 2304 x 1536 
  Objects:</p>
  
  <p>Then it starts finding objects with 2 fps.</p>
  
  <p>How do I change the video stream resolution to 1080p or 720p? The frame rate is very slow and this appears to be the fix.</p>
  
  <p>Can't find it within the makefile or cfg folder. Any thoughts? Is this an opencv problem? </p>
  
  <p>Thanks!</p>
  
  <p>cfg settings:</p>
  
  <pre><code>[net]
  batch=64
  subdivisions=8
  # Training
  #width=512
  #height=512
  width=320
  height=320
  channels=3
  momentum=0.949
  decay=0.0005
  angle=0
  saturation = 1.5
  exposure = 1.5
  hue=.1
  
  learning_rate=0.0013
  burn_in=1000
  max_batches = 500500
  policy=steps
  steps=400000,450000
  scales=.1,.1
  </code></pre>
  
  <p>I tried with the built-in camera and connected my phone(IP) and got 1080 on both with smooth results. I didn't find anywhere to change the webcam settings which are stuck on 2304x1536. Where would camera settings be located?</p>