Excessive Bandwidth Usage

[SherlockLin 2]

Bug Report

 

• Product: Emby Server

• Version: 4.9.0.30

• Server Environment: Synology NAS (DSM 7.2)

• Issue: Excessive Bandwidth Usage

 

Problem Description

 

When the streaming bitrate is set to 4K on the client, the server’s upload bandwidth usage consistently reaches 4K, even when the actual video bitrate is much lower. This results in inefficient bandwidth usage on the server.

 

Steps to Reproduce

 

1. Set the streaming bitrate to 4K on the client.

2. Play a low-bitrate video.

3. Monitor server upload bandwidth—it remains close to 4K.

Edited October 7, 2024 by SherlockLin

[Abobader 3335]

Hello SherlockLin,

** This is an auto reply **

Please wait for someone from staff support or our members to reply to you.

It's recommended to provide more info, as it explain in this thread:

Thank you.

Emby Team

[ebr 15650]

Hi.  This is how data delivery works.  The client requests data and the server returns it.  Whatever bandwidth is available to do that will be used.

The limits you set just determine the bitrate of the content.

[SherlockLin 2]

The original video resolution is only 720P, the client requests 4K data, the bandwidth used should be the bandwidth of 720P data not 4K data, right?

[Happy2Play 9431]

3 hours ago, SherlockLin said:

The original video resolution is only 720P, the client requests 4K data, the bandwidth used should be the bandwidth of 720P data not 4K data, right?

Correct as the only time file bitrate is inflated is when say transcoding happens on HEVC and converted to H264 bitrate can potentially get double if possible per client set quality to maintain the quality of the compression per the codec.

So you really need to go over a specific example of the issue you are seeing.

[SherlockLin 2]

I'm sure there's no transcoding happening, the playback info says it's a direct playback

[Happy2Play 9431]

Without real information all anyone can do is guess. 

 

[Luke 40006]

4 hours ago, SherlockLin said:

I'm sure there's no transcoding happening, the playback info says it's a direct playback

@SherlockLin

 

Hi there, let's look at an example. Please attach the information requested in how to report a media playback issue. Thanks!

 

[ebr 15650]

On 10/7/2024 at 12:33 PM, SherlockLin said:

The original video resolution is only 720P, the client requests 4K data, the bandwidth used should be the bandwidth of 720P data not 4K data, right?

The player requests the file and it is sent at whatever speed the connection will allow and the player just buffers in the extra amount up to a certain point.  The data is not sent at the exact speed of the video.

[SherlockLin 2]

Played to media from 22:29 to 23:07 on 10.9, resolution is 720p and compression format is H.264.

Attached is the log file and the time period of the traffic anomaly.

embyserver-63864115200.txt

[SherlockLin 2]

During this time 2 videos were played, the total size was about 1.8G, but as shown in the chart, the upload was over 52G.

57 minutes ago, SherlockLin said:

Played to media from 22:29 to 23:07 on 10.9, resolution is 720p and compression format is H.264.

Attached is the log file and the time period of the traffic anomaly.

embyserver-63864115200.txt 40.89 MB · 1 download

 

[Carlo 4552]

Hi,

Are you sure this traffic is from Emby and not something else running on the computer?
Do you have any torrent programs or file share programs?

[SherlockLin 2]

10 minutes ago, Carlo said:

Hi,

Are you sure this traffic is from Emby and not something else running on the computer?
Do you have any torrent programs or file share programs?

Yes, I'm sure it's from emby server upload, there was no other upload traffic in the meantime and my torrent uploads are speed-limited to 4MB/s max.

[SherlockLin 2]

I've found that this issue doesn't seem to have anything to do with the quality of playback the client chooses. It only has to do with the video being played. When I play a 1080p video, it turns out that the bandwidth is lower than 720p. No transcoding, direct play mode , very strange, here is the data comparison:

[SherlockLin 2]

BTW, I'm using the iOS client to test this, if you play it on Chrome, the traffic is normal.

[SherlockLin 2]

1 hour ago, SherlockLin said:

BTW, I'm using the iOS client to test this, if you play it on Chrome, the traffic is normal.

To summarize, on my iPhone, Safari, Chrome, and the App, there are traffic anomalies when playing certain videos. On Android, no problem playing using the App, problem playing using Chrome. On Mac, no problem playing using Chrome. I think it's somehow a problem with the buffering logic that's causing it to constantly be buffering.

[Carlo 4552]

@ebrLooking at the server log posted above I see the requests showing the requested range that's jumping all around. Could this be the source of the excessive bandwidth use?

Range=bytes=212983045-1381435201
Range=bytes=55050240-55574527,
Range=bytes=56196832-206929919
Range=bytes=211845120-212860927
Range=bytes=212983045-1381435201
Range=bytes=55115776-55574527
Range=bytes=56196832-206929919
Range=bytes=212041728-21286092

[Luke 40006]

3 hours ago, Carlo said:

@ebrLooking at the server log posted above I see the requests showing the requested range that's jumping all around. Could this be the source of the excessive bandwidth use?

Range=bytes=212983045-1381435201
Range=bytes=55050240-55574527,
Range=bytes=56196832-206929919
Range=bytes=211845120-212860927
Range=bytes=212983045-1381435201
Range=bytes=55115776-55574527
Range=bytes=56196832-206929919
Range=bytes=212041728-21286092

No, this is just the video player downloading pieces of the file at a time. Very normal.

One thing that can cause excessive bandwidth usage is users running improperly configured reverse proxies where the whole file gets sent back on every single partial request.

[SherlockLin 2]

3 hours ago, Luke said:

No, this is just the video player downloading pieces of the file at a time. Very normal.

One thing that can cause excessive bandwidth usage is users running improperly configured reverse proxies where the whole file gets sent back on every single partial request.

I'm not using a reverse proxy.

[Luke 40006]

On 10/9/2024 at 12:17 PM, SherlockLin said:

Played to media from 22:29 to 23:07 on 10.9, resolution is 720p and compression format is H.264.

Attached is the log file and the time period of the traffic anomaly.

embyserver-63864115200.txt 40.89 MB · 4 downloads

Hi, how do you know the bandwidth is all from emby server?

[SherlockLin 2]

On 10/10/2024 at 3:41 AM, SherlockLin said:

I've found that this issue doesn't seem to have anything to do with the quality of playback the client chooses. It only has to do with the video being played. When I play a 1080p video, it turns out that the bandwidth is lower than 720p. No transcoding, direct play mode , very strange, here is the data comparison:

The screenshot is the data I retested and monitored using ntopng, 8920 is the port Emby is listening on. First image shows the amount of data buffered in about three minutes under normal conditions (284MB), and second image shows the amount of data buffered in three minutes under abnormal conditions (1.63GB).

This problem can be reproduced 100%, if you need any help I can test it for you guys.

Edited October 14, 2024 by SherlockLin

[Carlo 4552]

Hi, would you be able to supply a 5-minute test sample for us to use to try and reproduce this issue?

Out of curiosity, if possible, could you try turning off HW transcoding, just to see if there is any difference in bandwidth used?

Thanks,
Carlo

[visproduction 275]

Is the original media 24 fps and the conversion with 720P 30 fps?  That's not needed.  Keep it at the original fps.  That would work a lot better and faster.  Changing 24 to 30 is really a bad idea.

Converting from AC3 Surround to Stereo, takes more effort than you would imagine.  It's probably also faster to convert to surround, although the file size would be larger.

[SherlockLin 2]

On 10/15/2024 at 12:34 AM, Carlo said:

Hi, would you be able to supply a 5-minute test sample for us to use to try and reproduce this issue?

Out of curiosity, if possible, could you try turning off HW transcoding, just to see if there is any difference in bandwidth used?

Thanks,
Carlo

HW transcoding is always off on my server, because my NAS doesn't support hardware decoding.

I tried to cut the video to 5 minutes, but the cut did not have the problem I described. Is it ok to give you the original video? It's about 1G.

[SherlockLin 2]

On 10/15/2024 at 5:18 AM, visproduction said:

Is the original media 24 fps and the conversion with 720P 30 fps?  That's not needed.  Keep it at the original fps.  That would work a lot better and faster.  Changing 24 to 30 is really a bad idea.

Converting from AC3 Surround to Stereo, takes more effort than you would imagine.  It's probably also faster to convert to surround, although the file size would be larger.

This is a video downloaded from Youtube, the original fps is 30.

Edited October 16, 2024 by SherlockLin