FlowPlayer - Quality Level Selection

[balderys]

Hi mangui,

could you please confirm that automatic bitrate switching is done after the current HLS segment is played and the next segment is from new bitrate? Or the algorithm is waiting while the buffer is empty?

[mangui]

automatic bitrate selection is performed each time a new segment needs to be downloaded, based on different params : current level, last dl bw, current buffer size, ...
it does not wait for the buffer to be empty to switch down

[balderys]

Thank you a lot.

Another question is what is the best way how to manually force switch to another bitrate? And if I switch manually, will be the behaviour the same as automatic switch -> switch is performed at next segment? Can I force the switch (does not matter if there is rebuffering) and continue from the same position in live stream (I expect that no)?

[mangui]

when manually switching (using hls.level = manual_level), switch will happen at next segment load, i.e. it will not interrupt any loading in progress.
if you want to force the switch at current pos, best is to force a seek after manually setting the level:

_hls.level = new_level;
_hls.stream.seek(current_pos);

[balderys]

Actually what does it mean "each time a new segment needs to be downloaded"? Does it mean next segment which is going to be played or in terms of HLS is it fourth segment because I have to have at least 3 segments in playlist prepared in advance?

[balderys]

Ok, but there is no current position in live stream if I'am correct?

[mangui]

hls.position will return the current media position (relative to playlist start)
it is also valid for live stream with flashls

[remizovvv]

Hello, mangui!
Could you tell about the manual switch mod of your plugin? And can I switch bitrate by clicking on the html element?
'Bitrateselect' plugin has onStreamSwitch method, which I can initialize by custom function. But does your plugin has a similar methods?

[mangui]

Hi @remizovvv
flashls provides API to trigger manual level switching, it is up to the player to use them.
if you are referring to FlowPlayer 'bitrateselect' plugin, it does not support flashls, a dedicated bitrate selection plugin would have to be written.

[remizovvv]

Thanks for the quick answer!
Yes, I use flowplayer) How can I use flashls API? Or this API for only connection between flashls and player ?

[mangui]

it is an ActionScript API, so obviously you need to do some Flash/AS3 coding to interface with it

[remizovvv]

I mean, can I call javascript function which applies directly to flashls and switches bitrate?
If no, and I must call only flowplayer API function, could you tell me what I should do in this case:

Flowplayer (in my project) gets stream link (.m3u8 file) from third-party-server (I can't influence on the formation of this file). This file contains three stream links (.m3u8 too) with the different bitrates. Flowplayer allows manual switch the bitrate with the 'bitrateselect' plugin, but your plugin doesn't work with it. What should I do to manual switch bitrate in this situation?

Thank you for explanation!

[mangui]

Hi @remizovvv
after relooking into it, it might be possible to use bitrateselect plugin straightaway, but it would require some modifications in flashlsFlowplayer.swf

basically flashlsFlowPlayer would have to report all available bitrates to FlowPlayer (it should fill bitrate info in Clip Object) , and also implement switchStream() method

[remizovvv]

Thanks for the answers, @mangui !
Now I know in what direction to think to solve my problem.

[mangui]

I dont have the bw to work on this now, but I just commited some commented codes that is reporting available bitrates to FlowPlayer.

with this code, FlowPlayer should in theory be able to detect available bitrates, and request bitrate switch,
then you need to implement switchStream()

https://github.com/mangui/flashls/blob/master/src/org/mangui/flowplayer/HLSStreamProvider.as#L468

NetStreamPlayOptions should indicate you the level on which you need to switch, through
NetStreamPlayOptions.streamName

see code triggering the level switch here : https://github.com/flowplayer/flash/blob/1caea54d3e7fa66b6496d556998052507a6d05a4/lib/common/src/actionscript/org/flowplayer/net/StreamSwitchManager.as#L73-L76

Cheers,
Mangui

[remizovvv]

What a surprise! Thank you very much!
Unfortunately, I'm not an expert on action script, but I'll try to understand.

[lerivin]

What are the parameters for bitrate switching? Our current player is always selecting the highest bitrate no matter the bandwidth available. Is there a previous setting that is remembered and always used?

my testing is done with Chrome's throttling and I've tried a few setting with no luck.

HLSSettings.capLevelToStage = true;
HLSSettings.startFromLevel = -1;

Any help/advice would be appreciative!