Faster media start up

[mraavi]

Our application stream Live media.
Media Start up time is 4 to 5 sec.
I am looking for ways to reduce media start time up time in order to provide best user experience.
Following are the list of call during media start up.

You can observe that the call in the list
MPD
init.mp4 for audio
1st audio segment
init.mp4 for video
1st video segment
get License call
2nd audio segment
3rd audio segment
2nd video segment
Media start only after downloading 2nd video segment. Segment duration is 6 sec.
Following are the abr and streaming configurations

mPlayer.configure({
            abr: {
                defaultBandwidthEstimate: 1000000,
                switchInterval: 6
            },
            streaming: {
                bufferBehind: 6,
                bufferingGoal: 6
            }
        });

Following is the mpd,

<?xml version="1.0" encoding="utf-8"?>
<MPD xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:mobitv="urn:mobitv" xmlns="urn:mpeg:dash:schema:mpd:2011" xsi:schemaLocation="urn:mpeg:dash:schema:mpd:2011 DASH-MPD.xsd" profiles="urn:mpeg:dash:profile:isoff-live:2011,urn:com:dashif:dash264" maxSegmentDuration="PT6S" minBufferTime="PT2S" type="dynamic" timeShiftBufferDepth="PT20M" minimumUpdatePeriod="PT8760H" availabilityStartTime="1970-01-01T00:00:19Z" suggestedPresentationDelay="PT11S" id="5062" publishTime="2019-12-11T05:23:54Z">
   <ProgramInformation>
      <Title>Media Presentation Description by MobiTV.</Title>
   </ProgramInformation>
   <Period mobitv:publishTime="2019-12-11T05:23:54Z" id="precambrian" start="PT0S" mobitv:thumbnails="150_T;640_T">
      <AdaptationSet contentType="video" mimeType="video/mp4" mobitv:qualityLevel="SD" segmentAlignment="true" startWithSAP="1" par="16:9" minWidth="640" maxWidth="1280" minHeight="360" maxHeight="720" maxFrameRate="60/2">
         <Accessibility schemeIdUri="urn:scte:dash:cc:cea-608:2015"/>
         <Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"/>
         <SegmentTemplate startNumber="0" initialization="$RepresentationID$/init.mp4" duration="6" media="$RepresentationID$/$Number$.m4s"/>
         <ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" value="cenc"/>
         <ContentProtection schemeIdUri="urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed" value="Widevine: SD"/>
         <ContentProtection schemeIdUri="urn:uuid:9a04f079-9840-4286-ab92-e65be0885f95" value="Playready: SD"/>
         <Representation id="V2200_W" codecs="avc1.4d401f" bandwidth="2384800" mobitv:average-bandwidth="2205862" mobitv:peak-bandwidth="2361517" width="960" height="540" frameRate="60/2" sar="1:1"/>
         <Representation id="V5000_W" codecs="avc1.640020" bandwidth="5120000" mobitv:average-bandwidth="5001378" mobitv:peak-bandwidth="5284876" width="1280" height="720" frameRate="60/2" sar="1:1"/>
         <Representation id="V864_W" codecs="avc1.4d401e" bandwidth="884736" mobitv:average-bandwidth="871321" mobitv:peak-bandwidth="944708" width="640" height="360" frameRate="60/2" sar="1:1"/>
      </AdaptationSet>
      <AdaptationSet contentType="audio" mimeType="audio/mp4" lang="eng" mobitv:qualityLevel="SD" segmentAlignment="true" startWithSAP="1">
         <Role schemeIdUri="urn:mpeg:dash:role:2011" value="main"/>
         <SegmentTemplate startNumber="0" initialization="$RepresentationID$/init.mp4" duration="6" media="$RepresentationID$/$Number$.m4s"/>
         <ContentProtection schemeIdUri="urn:mpeg:dash:mp4protection:2011" value="cenc"/>
         <ContentProtection schemeIdUri="urn:uuid:edef8ba9-79d6-4ace-a3c8-27dcd51d21ed" value="Widevine: SD"/>
         <ContentProtection schemeIdUri="urn:uuid:9a04f079-9840-4286-ab92-e65be0885f95" value="Playready: SD"/>
         <Representation id="A96_ENG" codecs="mp4a.40.5" bandwidth="98304" mobitv:average-bandwidth="101359" mobitv:peak-bandwidth="102064" audioSamplingRate="48000">
            <AudioChannelConfiguration schemeIdUri="urn:mpeg:dash:23003:3:audio_channel_configuration:2011" value="2"/>
         </Representation>
         <InbandEventStream schemeIdUri="urn:mobitv:event" value="id3"/>
      </AdaptationSet>
   </Period>
</MPD>

How to start the media right after LICENSE response? First audio and video segments are downloaded before the License call . why to wait till 2nd video segment download ?

[theodab]

What happens if you set the bufferingGoal a bit lower, like 5 seconds? Or 5.5 seconds?

[mraavi]

i tried setting bufferingGoal lower than 6 sec. That didn't help.

[theodab]

I'm not sure if I can do much more without actually being able to try out your content. Could you please provide the information necessary to reproduce this (manifest URI, DRM keys, etc)? If anything is confidential, you can send the details to our mailing address: shaka-player-issues@google.com

[raskri]

This might help?
Ignore your minBufferTime="PT2S" by setting:
player.configure('manifest.dash.ignoreMinBufferTime', true);
player.configure('streaming.rebufferingGoal', 0);

[mraavi]

@raskri i have tried this. Didn't help.

[joeyparrish]

@mraavi, if you can't provide us with a way to reproduce your problem, we will not be able to diagnose the issue. A copy of your MPD text is not useful without the content. If you can send an accessible manifest URL to shaka-player-issues@google.com, we can help you further.

Alternately, if the issue is not specific to your content, you could provide us with repro steps using the content in our demo app, which is all public.

[mraavi]

@joeyparrish Here is the mpd
https://live-integration-msp-edge.connectcdn.net/mm/dash/live/67812/LIVESERVICE_1234/group=TG_WIFI_HD.mpd
The issue can be reproduced with Shaka demo player as well
https://shaka-player-demo.appspot.com/demo/#audiolang=en-US;textlang=en-US;uilang=en-US;panel=CUSTOM%20CONTENT;build=uncompiled

[TheModMaker]

When we start playing, we'll start playing in the middle of a segment, so although we download the first segment, it won't contribute the whole time to the bufferingGoal/rebufferingGoal. So after we download the first segment, we may have only buffered 2 seconds. So if you set the rebufferingGoal to 6 seconds, it will require us to always download two segments. You should set the rebufferingGoal to a small number like 2 seconds and the bufferingGoal to a larger number like 30 seconds.

By playing your asset and throttling the network, I see us playing after we download the first segment with the default settings. So try reducing the rebufferingGoal.

[shaka-bot]

@mraavi Does this answer all your questions? Can we close the issue?

[mraavi]

@TheModMaker I have tried reducing rebufferingGoal to 1. It didn't help.
Did the configuration as below
mPlayer.configure('manifest.dash.ignoreMinBufferTime', true);
mPlayer.configure('streaming.rebufferingGoal', 1);

In fact this can be observed with Demo Shaka player and with the mpd i have provided.
Tested on Mac - Chrome Version 79.0.3945.88
I have uploaded a video with screen recording.
https://youtu.be/KnEKneQNigU
You can clearly see that, the video started after 2nd segment download.

It requires 3 segments on Samsung TV - Chrome Version 56.0.2924.0