playback video is choppy

Wowza Streaming Engine
1

I have a Mac running Wirecast and send the video via wireless internet back to the company’s Wowza server. I played back the video from Wowza server. The video is choppy: it play for a few seconds then freez a few seconds.

the video in Wirecast was set to output (flash, H.264 Video encoding, 720x480, 29.97fps, bitrate is 800Kbps. I didn’t send audio in the test.

The wireless internet most of the time can have 1Mbps upload speed.

What can I do to improve the video playback?

Thanks!

Emily

2

Emily,

I would try half that bitrate: 400kbs, and not much higher when you add audio.

Richard

3

It sounds like it is choking at 800kb/s, and that’s my experience too where the supposed up-speed, same as yours, seems adequate, but evidently isn’t. Lower bitrate means lower quality, but 400kb/s of h.264 video can be very good, depending on the input. In anycase, smooth playback is more important than resolution.

Richard

4

Have you looked at these options in the Application.xml:

Default:

<!-- suggested settings for video on demand applications -->
					<ReceiveBufferSize>24000</ReceiveBufferSize>
					<SendBufferSize>65000</SendBufferSize>
					<!-- suggest settings for low latency chat and video recording applications
					<ReceiveBufferSize>16000</ReceiveBufferSize>
					<SendBufferSize>16000</SendBufferSize>
					-->

I deleted the vod setting and uncommented the alternative settings. Better for you:

<!-- suggest settings for low latency chat and video recording applications -->
					<ReceiveBufferSize>16000</ReceiveBufferSize>
					<SendBufferSize>16000</SendBufferSize>

Richard

5

Sorry, VHost.xml (not Application.xml)

Richard

6

I’m not sure what else to do. Have you tried 600kbs?

Richard

7

We don’t need audio most of the time. Right now I just test video. If I lower the bitrate, do I still get the same quality of the video? I am pretty much satified with the video quality but it just didn’t playback continuously.

Thanks Richard.

Emily

8

Richard,

I would like to try to increase the buffer time. Can you please tell me what I should change in the configuration files? I don’t mind the delay. I need good video quality.

Thanks.

Emily

9

Is Application.xml or VHost.xml?

10

Thanks Richard.

I remember I saw one post said the default buffer time is 2 seconds. where can I find this line to modify it to a longer buffer time? I was thinking if I increase the buffer time in the server, when I playback the video, it may be smooth.

Emily