Develop Reference

Plyr audio player muted for the first second of audio

I am using Plyr audio player for my Rails app, along with Simulus.js.
I dynamically add audio source when the user clicks on different audio buttons. Then I launch the audio player with the .play() method.
However, the beginning of the track can't be heard. You can try it out on this URL, by taping the first audio player. If you put back the audio cursor to the beginning, then you can hear the very beginning of the track.
Here is my HTML:
<audio class="player" controls data-dicteeModule-target="player">
<source class="player-source" src="<%= dictee_modules.first.audio_url %>" type="audio/mp3" />
</audio>
Here is how I initialize the player:
initialize() {
const players = document.getElementsByClassName('player');
var player = [];
Array.from(players).forEach(function (ele, i) {
player[i] = new Plyr(ele, {
controls: ['progress']
});
});
}
Here is my Stimulus onclick action:
var player = this.playerTarget;
var source = audio.getAttribute("data-audio-source");
var audioSource = player.getElementsByClassName("player-source")[0];
audioSource.src = source;
player.load();
player.addEventListener('canplay', (event) => {
player.play();
});
Any idea why the very beginning of the track is not heard?
Thanks.

This happens to me too on various websites that need to use audio after no audio was used for a while, even on YouTube. I'm using Chrome 104.0.5112.81 on Windows 10.
It's likely a driver issue you can't do much about (assuming YouTube would fix it if they could). It looks like Windows or Chrome ends up dimming the sound way too quickly, and takes too long turning it back on.
Unfortunately I couldn't find anything on Google yet. It seems hard to make Google understand this query, it only returned results about audio preventing PC sleep mode (or other unrelated common issues), no matter how I phrased it. Could also indicate it's just a very obscure issue with one or a few particular drivers.

Get notified when <video> time changes

I would like to display the current percentage of the video using a Firefox extension.
I know I can get the current time and the duration with the Youtube Player API:
player = document.getElementById('movie_player')
currentTime = player.getCurrentTime()
duration = player.getDuration()
And I can add a node to the DOM with appendChild or insertBefore.
But I don't understand how to update periodically the DOM as time goes by.
I tried to understand how the Youtube Player updates the time display using the inspector but it didn't help me:
I guess I should use events somehow but I don't know what event could be triggered periodically without user intervention (click, hover, ...).

Sounds like you're looking for the timeupdate Media Event:
The time indicated by the element's currentTime attribute has changed.
const vid = document.querySelector('video')
vid.addEventListener('timeupdate', e => {
console.log(vid.currentTime)
})
<video autoplay width="320" height="240" controls>
<source src="http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ForBiggerFun.mp4" type="video/mp4">
</video>

Javascript autoplay video (mp4) on Opera browser?

I have made a website which we use on a TV to welcome guests/customers to our business. There's a SQL database which we write their names to be presented on the screen, and there is also a video which is playing in a different frame on the same website.
This all works very well on desktop PC Chrome. But we use the built in browser in the TV (which is a business model used for stuff like this). The browser is Opera and it supports HTML5.
Problem is that after a while, can be 2 hours, can be a day, it will stop playing the video, and just show a black frame.
This is the code:
<source src="video/video1.mp4" type='video/mp4'/>
</video>
<script type='text/javascript'>
video_count =1;
videoPlayer = document.getElementById("video");
function run(){
video_count++;
if (video_count == 3) video_count = 1;
var nextVideo = "video/video"+video_count+".mp4";
videoPlayer.src = nextVideo;
videoPlayer.play();
videoPlayer.loop();
};
</script>
This will play the files named video1.mp4 and video2.mp4... etc. Right now there is only one file in this folder called video1.mp4, and it will autoplay and it will loop. But it will fail to autoplay after a while and just show a black frame.
Any ideas?
Thanks!

I'd recommend looking into video events with javascript in this case if you're starting to see bugs.
For example (from Detect when an HTML5 video finishes post) you could start playing your next video like this:
<script type='text/javascript'>
document.getElementById('myVideo').addEventListener('ended',myHandler,false);
function myHandler(e) {
// What you want to do after the event
}
</script>
You could simply move on to the next video, or seek back to 0 on its timeline and play it again. The other option if you're wanting to loop 1 video, you'd be better using the loop option in your <video> tag:
<video loop>
<source src="video/video1.mp4" type="video/mp4">
</video>

Game development: restart the sound(<audio> element) before it ended playing

I ran into some issues regarding my small-web-game project:
I have some sound files, given in HTML like this:
<audio id="shotSound" preload="auto">
<source src="../sound/shot.mp3" type="audio/mpeg">
Your browser does not support the audio element.
</audio>
the preload="auto" should load the content immediately on page init right?
Now I'm using javascript to trigger the sound when I need to (key press):
var audio = document.getElementById("shotSound");
audio.play();
This works, but if I try to shot continuously or just faster(one shot after another) it won't work for shots after the first one. So, what happens if I hold the "shot" button: the sound is heard like it would be on repeat - which is obviously wrong.
Any ideas/suggestions are very welcome!
If I was unclear, please do let me know.
Thank you

Don't put the audio-tag into the HTML document. Preload the sound-effect in Javascript using
shotSound = new Audio();
shotSound.src = "../sound/shot.mp3";
shotSound.load();
Keep the shotSound variable in scope, so it doesn't get garbage-collected. Then, when you need to play a sound, create a new Audio object:
new Audio("../sound/shot.mp3").play();
It will play immediately because the sound-file will already be cached. And because it's a new audio-object, it won't interrupt other instances of the same effect playing in parallel.

Dynamically using the first frame as poster in HTML5 video?

I'm wondering if there's any straightforward way to achieve this effect, without needing backend code to extract a frame, save it as a jpg and database it somewhere.
An effect whereby the first frame of the video just shows up as the poster when the video loads would be so helpful (it would only work if the browser can play back the video obviously, which might be a little different from how poster traditionally works, but that is not a concern.

Did you try the following?
just append time in seconds #t={seconds} to source URL:
<video controls width="360">
<source src="https://test-videos.co.uk/vids/bigbuckbunny/mp4/h264/1080/Big_Buck_Bunny_1080_10s_1MB.mp4#t=0.1" type="video/mp4" />
</video>
I have chosen a fraction of second (0.1) to keep number of frames small, because I have the suspect that if you put 1 second, it would "preload" the first 1 second of video (i.e. 24 frames or more ....). Just in case ...
Works fine on Chrome and Firefox on desktop :)
Works not on Android mobile, though :(
I did not test on iOS, iPhone, IE yet ??
Edit May 2021:
I realized that many modern browsers now show automatically a poster of first frame.
Seems like they heard us :-)

To make it simple you can just add preload="metadata" to your video tag and the second of the first frame #t=0.5 to your video source:
<video width="400" controls="controls" preload="metadata">
<source src="https://www.w3schools.com/html/mov_bbb.mp4#t=0.5" type="video/mp4">
</video>
Best of luck!

There is a Popcorn.js plugin called Popcorn.capture which will allow you to create posters from any frame of your HTML5 video.
There is a limitation that is imposed by the browser that prohibits reading pixel data of resources requested across domains (using the canvas API to record the current value of a frame). The source video must be hosted on the same domain as the script and html page that is requesting it for this approach to work.
The code to create poster using this plugin is quite simple:
// This block of code must be run _after_ the DOM is ready
// This will capture the frame at the 10th second and create a poster
var video = Popcorn( "#video-id" );
// Once the video has loaded into memory, we can capture the poster
video.listen( "canplayall", function() {
this.currentTime( 10 ).capture();
});

I recently did this for a recent project that works on desktop and mobile. The trick was getting it to work on iPhone.
Setting preload=metadata works on desktop and android devices but not iPhone.
For iPhones I had to set it to autoplay so the poster image automatically appears on initial load. iPhones will prevent the video from auto playing, but the poster image appears as the result.
I had to do a check for iPhone using Pavan's answer found here. Detect iPhone Browser. Then use the proper video tag with or without autoplay depending on the device.
var agent = navigator.userAgent;
var isIphone = ((agent.indexOf('iPhone') != -1) || (agent.indexOf('iPod') != -1)) ;
$videoTag = "";
if(isIphone()) {
$videoTag = '<video controls autoplay preload="metadata">';
} else {
$videoTag = '<video controls preload="metadata">';
}

You can set preload='auto' on the video element to load the first frame of the video automatically.

Solution for #2, #3 etc. frames. We need attach disposable handler .one() for resetting default frame.
<video width="300" height="150" id='my-video'>
<source src="testvideo.mp4#t=2" type="video/mp4" />
</video>
$(function () {
let videoJs = videojs('my-video');
videoJs.one('play', function () {
this.currentTime(0);
});
});

I found a great way to dynamically add poster to a video!
To show the desired frame from video (in my case it's the frame at 1.75 seconds) - add preload="metadata" to the video element and #t=1.75 to the end of source URL.
Add eventListener to the video element that will listen for play event only once.
Once the event is emitted reset the video time.
<video width="100%" controls="controls" preload="metadata" id="myVid">
<source src="path/to/your/video#t=1.75" type="video/mp4">
</video>
<script>
var el = document.getElementById('myVid');
el.addEventListener('play', () => {
el.currentTime = 0;
}, { once: true });
</script>