BBB Video Quality & Bandwidth Question

[Luis Rosario]

So I want to understand at what point the settings that affect video quality & bandwidth kick in?  Video quality compresses the video, is this happening on the client side or on server side.  Same with bandwidth?  And it seems when enabling h264 you would be double compressing the video. Does that sound right?  It would be awesome to see a diagram as to when the compression and bandwidth limiting settings actually occur in the architecture. Thanks!

-Luis

[Fred Dixon]

Hi Luis,

> So I want to understand at what point the settings that affect video quality & bandwidth kick in?  

The options for different video resolution are presented to users when they elect to share their webcam.  The drop-down menu gives options such as

  Low Quality

  Medium Quality

  High Quality

  HD Quality

You can see the specifications for the various options in the profiles.xml file on a BigBlueButton server, such as

  https://demo.bigbluebutton.org/client/conf/profiles.xml

>  And it seems when enabling h264 you would be double compressing the video.

Your switching between h.263 and h.264 encoding in the client (there is no double encoding).  

> It would be awesome to see a diagram as to when the compression and bandwidth limiting settings actually occur in the architecture.

The bandwidth limitations are specific to each user.  If their are limitations in the user's upstream bandwidth, the BigBlueButton client (specifically Flash) will start dropping video frames in the upload.  If there are limitations in the user's downstream bandwidth, the BigBlueButton server (specifically red5) will start dropping frames it's trying to send to the user.

The bandwidth issues for one user do not affect the video performance of other users.

Regards,... Fred

On Thu, Sep 29, 2016 at 12:02 PM, Luis Rosario <lu...@groovetemple.tv> wrote:

So I want to understand at what point the settings that affect video quality & bandwidth kick in?  Video quality compresses the video, is this happening on the client side or on server side.  Same with bandwidth?  And it seems when enabling h264 you would be double compressing the video. Does that sound right?  It would be awesome to see a diagram as to when the compression and bandwidth limiting settings actually occur in the architecture. Thanks!

-Luis

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[Luis Rosario]

Thanks Fred for clarification.  And I'm aware of the profiles config files ect... Example case: If I have a webcam profile setting that targets HD and I limit bandwidth to a 2.5 Mb stream, the users on the other end will need at least have that much downstream to video view camera without decreased video quality?  And if they don't then playback is affected by what we set on the video quality & bandwidth settings, correct?

[Fred Dixon]

Hi Luis,

> Example case: If I have a webcam profile setting that targets HD and I limit bandwidth to a 2.5 Mb stream, the users on the other end will need at least have that much downstream to video view camera without decreased video quality?  

Correct.  If you run a network monitoring tool such as bmon on the server, and test it with just two yers, you can see the actual bandwidth coming in and out

> And if they don't then playback is affected by what we set on the video quality & bandwidth settings, correct?

The creation of a recording depends on the quality of incoming audio and video, so it's only the upstream bandwidth from a user to the BigBlueButton server that's going to affect the quality of the captured media (and thus the recording).

Regards,.. Fred

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[Luis Rosario]

Great!  Thank you for the feedback Fred!

-Luis

On Thursday, September 29, 2016 at 9:02:41 AM UTC-7, Luis Rosario wrote:

[Shahryar Razmjoo]

Hi Dear Fred

first of all, I want to thank you for all the kind support which you give us. you are a generous man. 

My BBB server is running on 12Core with 16Gb Ram with 100Mbyte/S internet speed and 1Gb/s Bandwith 

I need to have a very high-quality video when I'm as a moderator. I pick High Defenition but the video is still not having quality.

Could you please tell me which configuration can make my video high quality.

I also check the Profile.xml but all of the Profiles value is the same and just the size of the video is different 

for example, the wide Profile which is a high definition :

for getting high video quality which of these parameters should change to give me the highest video quality.

 <profile id="wide">

        <locale>

            <en_US>Widescreen</en_US>

           /locale>

        <width>1280</width>

        <height>720</height>

        <keyFrameInterval>5</keyFrameInterval>

        <modeFps>15</modeFps>     

        <qualityBandwidth>0</qualityBandwidth>

        <qualityPicture>90</qualityPicture>

        <enableH264>true</enableH264>

        <h264Level>2.1</h264Level>

        <h264Profile>main</h264Profile>

    </profile>

i really need some help to improve my video quality.

Best Regards

Shahryar Razmjoo

On Thursday, September 29, 2016 at 7:40:38 PM UTC+3:30, Fred Dixon wrote:

Hi Luis,

> So I want to understand at what point the settings that affect video quality & bandwidth kick in?  

The options for different video resolution are presented to users when they elect to share their webcam.  The drop-down menu gives options such as

  Low Quality

  Medium Quality

  High Quality

  HD Quality

You can see the specifications for the various options in the profiles.xml file on a BigBlueButton server, such as

  https://demo.bigbluebutton.org/client/conf/profiles.xml

>  And it seems when enabling h264 you would be double compressing the video.

Your switching between h.263 and h.264 encoding in the client (there is no double encoding).  

> It would be awesome to see a diagram as to when the compression and bandwidth limiting settings actually occur in the architecture.

The bandwidth limitations are specific to each user.  If their are limitations in the user's upstream bandwidth, the BigBlueButton client (specifically Flash) will start dropping video frames in the upload.  If there are limitations in the user's downstream bandwidth, the BigBlueButton server (specifically red5) will start dropping frames it's trying to send to the user.

The bandwidth issues for one user do not affect the video performance of other users.

Regards,... Fred

On Thu, Sep 29, 2016 at 12:02 PM, Luis Rosario <lu...@groovetemple.tv> wrote:

So I want to understand at what point the settings that affect video quality & bandwidth kick in?  Video quality compresses the video, is this happening on the client side or on server side.  Same with bandwidth?  And it seems when enabling h264 you would be double compressing the video. Does that sound right?  It would be awesome to see a diagram as to when the compression and bandwidth limiting settings actually occur in the architecture. Thanks!

-Luis

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