Repeated buffering with RTMP and JWPlayer 6

Wowza Streaming Engine
1

Hello,

We’re using Wowza and JWPlayer 6 with flash and RTMP.

We get reports that buffering occurs in the middle of a movie and also that sometimes the audio will continue to play, but the video will buffer or stop. This seems to be an intermittent problem, but occurs fairly regularly.

Are there any suggestions for how to resolve this or what we should look into that may effect this?

Thank you!

2

Just wanted to add, that the bitrate for one of the videos that experienced this is: 695364

3

That could easily be too high for many clients. Some clients’ bandwidth might fluctuate above and below that bitrate, causing intermittent problems: buffering and choppy playback, audio continuing with video frozen.

The best solution is ABR streaming. You encode 2 or more bit rate versions. They have to be key frame aligned with each other. Expression 4 Encoder can do this:

https://www.wowza.com/docs/how-to-encode-video-on-demand-content

ABR configuration is covered in the vod tutorial:

https://www.wowza.com/docs/how-to-set-up-video-on-demand-streaming#ABR

JW Player 6 handles does ABR (RTMP Dynamic Streaming), there is an example here:

https://www.wowza.com/docs/how-to-use-jw-player-with-wowza-streaming-engine

Richard

4

I assumed it as bps. So it is about 700kbs.

Richard

5

It is probably a waste of time with FFmpeg, as you noticed is noted in the article. If you are going to use Expression 4 Encoder or another one (maybe Handbrake works too, if I remember reports) that does key frame alignment correctly you can have whatever seems necessary. If some of your audience needs 200mbs streams, you can encode a 200mbs rendition. But not later, you have to encode all renditions at once to get alignment.

Richard

6

Yes, encode the different bitrate file renditions at the same time, as Richard directs, in order to ensure keyframe alignment.

Follow the examples that Richard links to above for JW player ABR playback.

Daren

7

rrlanham,

My mistake, that’s the bps, not kbps, but the actual bitrate.

8

Ah okay, so that bitrate is still probably too high?

We’re using ffmpeg to convert our videos into an mp4 container. After reviewing the link you provided, it looks like ffmpeg doesn’t support Multi-bitrate encoding. We have it setup similar to the example used for ffmpeg, with the following “thresholds”:

VIDEO_480P_MAX_BITRATE_TOLERANCE = 1800000;

VIDEO_480P_TARGET_BITRATE_REENCODE = 1400000;

VIDEO_720P_MAX_BITRATE_TOLERANCE = 3600000;

VIDEO_720P_TARGET_BITRATE_REENCODE = 2800000;

AUDIO_480P_MAX_BITRATE_TOLERANCE = 128000;

AUDIO_480P_TARGET_BITRATE_REENCODE = 96000;

AUDIO_720P_MAX_BITRATE_TOLERANCE = 192000;

AUDIO_720P_TARGET_BITRATE_REENCODE = 128000;

Should we lower these?

Thanks!

9

Hi Richard,

So, would you suggest be to encode our videos in multiple bitrates, then with JWPlayer specify the alternative bitrates so the client can switch between them?

Thank you