Correct Video Settings for Webcasting

Conversations around originating a webcast for conference, including cameras and mixers.
richphillips
New Member
Posts: 15
Joined: Mon Sep 26, 2011 8:04 am

Correct Video Settings for Webcasting

Postby richphillips » Wed Mar 29, 2017 11:11 am

Brethren:

I have received a lot of valuable advice through this forum, so I thought I would return to the well again.

My webcasting setup is pretty simple. Sony DVI-70 PTZ camera: connected to the Extron IN1508 video switcher/scaler; video from the output port on the rack to an Atlona HD-AT-120 converter; hdmi video from the Atlona to a Terradek VidiU encoder; then off to the internet.

The camera is standard definition. While it is great to have the PTZ functions of pan, tilt, zoom, etc. the resolution is only 480i. All the remote receiving sites complain about the lack of resolution of the video picture. Eventually, I will make some camera changes, but in the mean time I am looking for some advice on the proper settings for the equipment which might improve the video quality sent and received.

I have the In1508 switcher set to output 720p. I have the Atlona set to output at 1280x720p. I have the VidiU set to output medium quality video. The VidiU does not recommend a higher resolution because of my upload bandwidth.

My upload speed is 4.5 Mbs. Most of my remote sires have plenty of download bandwidth, 5-12 Mbs.

Please let me know what you think.

Thanks

CalS201
New Member
Posts: 26
Joined: Fri Jan 28, 2011 3:59 pm
Location: Sunnyvale, CA

Re: Correct Video Settings for Webcasting

Postby CalS201 » Thu Mar 30, 2017 3:04 pm

I can suggest three things that affect the clarity of your picture.

1. The "medium" quality setting (700kbps) of the VidiU cannot encode the 720P signal and give a clean crisp result if there is any movement or noise in the picture. "Medium" quality setting is OK for a 480i or 480p signal. The "HD(2100kbps) setting is OK for a 720P signal.

2. Upscaling your camera signal (480i) with the IN1508 Switcher to 720P is counter-productive. It only forces you to use faster encoder "quality" settings without any increase in "real" resolution or clarity.

3. Any noise or ghosting (from low light conditions in chapel and mismatched coax cables) in the original camera signal can cause the Switcher, Atlona, and VidiU Encoder, to each give suboptimal results. Noise also consumes a excessive amount of encoder kbps which leaves even less kbps for the actual picture information. Increasing the light level in the chapel can have a very positive effect on the picture.


As a test on a Saturday morning, you could turn off the wifi, then setup a projector/receiving computer in the cultural hall, and setup your webcasting equipment in the chapel of the same bldg. Connect the camera directly to the projector's composite input and note the quality (look for noise and ghosting) - then move the camera outside and note the quality when using more light. Now connect the camera to the Atlona and program the Atlona to output a 480P HDMI signal to the VidiU. Setup the VidiU for "Medium" quality broadcast and do a test webcast to the receiving computer/projector - note the quality. Move the camera outside and note the quality. Change the Vidiu to "High" and repeat the process. Now add the Switcher into the signal path and look at the resultant quality using "upscaling" to 720P and without upscaling (480P). This process should help you see what affects the final picture quality at the projector.

Finally, if you can borrow someones HD camcorder, you can plug it into the VidiU, set the quality to "High" or "HD", and see the result on the projector. You should see a better quality picture.

Good luck.

richphillips
New Member
Posts: 15
Joined: Mon Sep 26, 2011 8:04 am

Re: Correct Video Settings for Webcasting

Postby richphillips » Thu Mar 30, 2017 3:43 pm

Thanks for the suggestions. The camera is mounted to the ceiling so I don't want to take it down. I should be able to plug a composite video cable in the back of it to do some testing though. I think our chapel has pretty good lighting. We have a building only 2 years old and they have added four large windows to let in lots of light. I will try your suggestions of direct inputs versus casted

Sounds like I need to set the switcher back to 480p and keep the encoder at medium for now.

However, we have a little Sony HDX-240CX handicam that I believe outputs 720p. It has an hdmi out port and a cable to adapt that to two rca audio outputs and one rca video output. If I connect this to the video in port in the rack, could I set the switcher to 720p, the atlona converter to 1280x720p and the vidiu to HD. Would that be optimal? I think my 4.5 Mbs upload would handle HD; just need to have a good HD video to get to it.

CalS201
New Member
Posts: 26
Joined: Fri Jan 28, 2011 3:59 pm
Location: Sunnyvale, CA

Re: Correct Video Settings for Webcasting

Postby CalS201 » Thu Mar 30, 2017 5:56 pm

If you use the RCA video output adapter of the HD camcorder you get 16:9 480i/p (720X480) video. Optimal settings would be the same as for your EVI-D70 camera and the quality would be similar.

If you use the HDMI output of the HD camcorder you get 16:9 720P or 1080i/p (1280X720 or 1920X1080) video. With HDMI you should connect directly to the VidiU and use the "HD". The picture quality should be better than your SD camera (or HD camcorder when using it's SD output).

richphillips
New Member
Posts: 15
Joined: Mon Sep 26, 2011 8:04 am

Re: Correct Video Settings for Webcasting

Postby richphillips » Tue Apr 18, 2017 7:32 am

Thanks CalS201:

Your response got me to dig a little deeper. I found that the switch has a DVI-D input. I am going to use an HDMI to DVI-D cable and input the Sony HDX-240CX camera into the switch. Then set the switch to upscale to 720p for the switch output. I can then take the switch output (after converting it back from RGB to HDMI) and put it directly into the VidiU and stream at 720p. That way I can still switch between cameras and other inputs if I have them. I am going to use the HD camera for tight shots of the speaker and use the PTZ camera for other shots.

I am hoping the 720p output will give the receive sites better picture quality; certainly for the tight shots. Testing it tonight and planning to try it for a special conference we are having this weekend.

If you have any comments, that would be appreciated.

CalS201
New Member
Posts: 26
Joined: Fri Jan 28, 2011 3:59 pm
Location: Sunnyvale, CA

Re: Correct Video Settings for Webcasting

Postby CalS201 » Tue Apr 18, 2017 4:43 pm

Rich,

If your Video Switcher supports DVI-D but not HDMI, then it may also be limited to maximum of 1024X768 resolution. Your camcorder can only output 1280x720 and 1920x1080. It might be worth checking your Switcher's specs. What model do you have?

Cal

richphillips
New Member
Posts: 15
Joined: Mon Sep 26, 2011 8:04 am

Re: Correct Video Settings for Webcasting

Postby richphillips » Tue Apr 18, 2017 5:03 pm

Cal:

It is an Extron IN1508. This is the link to the spec page......... http://www.extron.com/product/product.aspx?id=2131#spec


Return to “Webcasting”

Who is online

Users browsing this forum: No registered users and 1 guest