Roku Developer Program

[dynamicmindset]

I have an application for live streaming using roVideoScreen.
After powering Roku and starting the application live streams start almost instant, but after a couple of opening/closing the video screen the buffer time increases dramatically.
It also happens with other Roku applications.
What could be the problem?

[mihaimarian]

We are seeing the same exact problem. The video stream goes from starting almost instantly to as long as 20 to 30 seconds. After a reboot of the Roku box it starts instantly again.
Can someone please help.

[RokuMarkn]

You can use the debug screen to check the network bandwidth that your unit is detecting. Perhaps what's happening is initially after a reboot it thinks your network is fast but after some use it recalculates it as a slower speed that takes longer prebuffering time.

--Mark

[RokuKevin]

Debug bandwidth settings screen:
Bitrate Debug Info on screen: Home 5x, Rew 3x, FF 2x

Note that there is currently a bug that makes it not interact with HLS streams properly.

--Kevin

[mihaimarian]

"RokuKevin" wrote:
Debug bandwidth settings screen:
Bitrate Debug Info on screen: Home 5x, Rew 3x, FF 2x

Note that there is currently a bug that makes it not interact with HLS streams properly.

--Kevin

So does this mean that this behavior I am seeing is normal due to the bug ?

[RokuKevin]

No. My post was just telling you how to get to the bandwidth screen that RokuMark was referring to. I also wanted to let you know that the bandwidth screen does not currently interact with StreamFormat="hls" streams....

The bandwidth screen should help you measure the bandwidth your box is seeing, which may be cause of the longer buffer time you are seeing.

--Kevin

[mihaimarian]

We are testing with the roku box hooked up to the same network that the streaming server is on. This behaviour happens no matter how much bandwidth it has. Also the behaviour always repeats. When you restart the roku you get very fast video start times, then after a few times that you play some live streams, it slows down drastically. We will do the testing with the debug however I do not think it is a available bandwidth issue.

[mihaimarian]

We have done some testing in debug. Below are our findings. As you can see it is clear that there is something going on that is not due to network bandwidth going down. As I have specified the stream server and roku are in the same network, and this behavior happens with other channels live streams as well.

Roku
Software: 2.9 - build 1529
Hardware version: model N1101
Serial number : D0D029016644

Network: roku + streaming server
Bandwidth: 100mbps
Speedtest: download -> 37222; upload -> 39956

Roku with playback debug enabled:

FIRST TESTS ON OUR PRIVATE CHANNEL
Max speed: 10 mbps when powering Roku
The speed decreases in time after playing live streams: 5.6 mbps, 1.2 mbps, 0.8 mbps
If the HLS bandwidth is set to 932 and Roku calculates the network bandwidth lower than 0.9:
Debug message: Cannot play 0.9 mbps stream on your 0.5 -> 0.9 mbps network because starting at 5:30 the stream needs 0.7 mbsp in the next 6 seconds (0.9 mbps).
If the HLS bandwidth is set to 640 and Roku calculates the network bandwidth greater than 0.6 (eg: 0.8-) : the stream plays instantly


OTHER TESTS ON Spacevidcast and OUR CHANNEL
Spacevidcast (live)
19:10 -> 10 mbps
19:15 -> cannot play 0.8 mbps stream on your 0.6 mbps network because starting at 1:28, the streams needs ...
19:16 -> 1.1, 1.3 mbps
loading, please wait -> makes buffer when playing and stays a lot (more than 5 minutes - it doesn't start again)
19:22 -> cannot play ... on your 0.1 mbps network
19:23 -> cannot play ... on your 0.2 mbps network ... 0.3 mbps
19:24 -> cannot play ... on your 0.4 mbps network

OUR CHANNEL
19:25 -> 1mbps -> plays instantly
19:30 -> 0.7 mbps
19:34 -> 1.1 mbps

Starting from a difference of 0.1 mbps between the bandwidth needed by the stream and the network calculated bandwidth the stream stays longer on the buffering phase (eg: 0.6 (or lower) mpbs stream on your 0.7 mbps network)

--reset ROKU --
OUR CHANNEL
19:48 -> 10mbps

Spacevidcast
19:48 -> 10mbps
19:53 -> Cannot play 0.6 mbps on your 0.7 mbps network
19:40 -> Cannot play 0.6 mbps on your 0.7 mbps network
19:41 -> 0.8 mbps
19:56 -> Cannot play 0.3 mbps on your 0.7 mbps network

Conclusions:
When powering/reseting ROKU the speed is 10mbps.
After playing some live streams the speed decreases. When it calculates the network bandwidth as beeing with 0.1 greater than the stream bandwidth, or lower the buffer time is longer.
The network speed eventually increases again and decreases again but not very significantly.

[RokuMarkn]

Well, it certainly looks to me like network bandwidth is the issue. Initially Roku thinks the network is 10 mbps because it hasn't seen any traffic yet. As you start playing, it gradually homes in on the correct speed, which seems to be down below 1 mbps. The long startup times confirm this, since if it were erroneously measuring a low bandwidth which was actually much higher, the stream would start quickly. So the question is why your Roku is getting such low bandwidth from your network.

Is the Roku connected wirelessly? If so perhaps there's some wifi interference.

--Mark

[mihaimarian]

IT IS NOT THE NETWORK.
This roku box is connected with a wire to our core switch a CIsco 6509.
Our stream server is on the same network.
We have multiple Gigabit fiber pipes to the internet.
It is not the network.
As you saw in our test we did a speed test from a laptop connected to the same switch as the roku box.
This is not a network issue.
Also if i fake set the stream size below what the roku "thinks" the network speed is it starts instantly and never buffers. There is another root cause here.

PS.

I am more then willing to give you a an account on our private channel to test yourselves.
But this is happening with not just our cahnnel, and not just on one roku player.