Is there a way to change the playback speed of audio in the browser? What is best to accomplish this task, html5 audio, or flash, or something else? Are there any specific libraries that would help with this?
Use the Web Audio API.
In the following code I answered your other question.
best way to loop audio in the browser?
Modify the code in my answer above as follows for a playback speed example.
Right below
source.loop = loopOnOff;
add
source.playbackRate.value = 1; // change number to between 0.10 to 10 (or larger/smaller) to test.
You can also run the html audio tag through the web audio api and add effects processing.
Interesting question there,
HTMl5 will have player speed control will have speed control..
A couple of noteworthy upcoming features are playbackRate and defaultPlaybackRate. As you can probably imagine, these fellas let us alter the speed and direction of playback. This functionality could be used for fast-forward and rewind functions or perhaps to allow users to tweak the playback speed so they can fit more podcasts into their day.
audio.playbackRate returns 1 at normal speed and acts as a multiple that is applied to the rate of playback. For example, setting playbackRate to 2 would double the speed, while setting it to -1 would play the media backwards.
audio.defaultPlaybackRate is the rate at which the audio will play after you pause and restart the media (or issue any event for that matter).
Flash Player may help( but it will be customized one you may create, with stream buffer, you need to define the player speed once buffer has the content to play.
Sound easy but will take a lot effort,
Refer VLC opesource for better Idea, its documented with ffmpeg which works with Audio,
and works with client software, in browser ti will be heavy, refer Just to have idea.
I hope this may help :)
Related
I'm developing an application, where it is necessary that a video is exactly at the playback position, where it should be if there were no lack of data, even if there is such.
eg. video.currentTime == timeSinceTheVideoWasStarted
The tolerance is about 0.1s and it is also possible to increase or decrease the playback speed a little bit to match the time.
All the media data is cached in a ObjectURL, but the decoding may be slow, because the application is very computation intensive.
I thought about setting the correct playback time at the playing event, but when data is present again and the currentTime is updated this will case the next lack of data.
I'm using the video element as a video texture source in WebGL as described here.
The fixed points are that the video is downloaded from a local server (for example http://localhost:8000/assets/foo.mp4) and displayed on WebGL. Your Soulutions may include different video decodings than the native <video>.
To reproduce it: Do something CPU intensive and play a video - it won't be smooth. (As you would expect)
I hope you can help me.
EDIT:
The main thing I worry about is the situation, I aleady experienced many times while nornaly working, likely windows itself is doing some sync disk IO, which causes everything to wait, even the mouse cursor...
I'll try it out to compensate small time differences (< 1s) by the playback speed
I'm currently helping a friend develop a web application in which I need ~6 audio tracks (all using the same time signature) to continuously loop and stay in sync. To give context, it is a typeface-music pairing application where as soon as a typeface is chosen, the associated audio loop starts playing and as the user keeps picking typefaces, the tracks layer and begin to resemble a song.
I've tried using SoundJS and the Buzz sound library, but I keep running into the same problem: there is always a slight delay between loops. This would be fine if all my audio tracks were the same length, but they aren't, so very quickly things go out of sync.
This seems to be a known problem, but I can't seem to find any answer to how to fix it. I came across Hivenfour's SeamlessLoop 2.0, but - unless I'm using it completely wrong - it doesn't actually seem to work (setting a volume returns an error).
If anyone has experience with this, I would truly appreciate any input! Thanks :)
SoundJS WebAudioPlugin uses a look ahead approach with web audio that will loop seamlessly, which is described here in a what will probably be a very helpful on audio timing.
Also be aware that some compression formats will insert white noise into sounds. I believe mp3 does this. WAV is supported broadly and does not.
As for HTMLAudioPlugin, we loop as smoothly as the browser will allow but it does not have the same precision as WebAudio.
Hope that helps.
I have limited knowledge on JS/JQuery but I am wondering if you can detect the end of a HTML5 video and then Play the video in reverse and then play it from the start so basically an endless loop playing forwards and then backwards?
Using JQuery/Javascript
Streaming video codecs are optimised to be played forward so, while there is a playbackRate property of HTML5 video which you might be able to use to reverse the playback of your video (try setting it to -1), the result is probably not going to be particularly satisfactory.
A better approach would be to create an additional video at the encoding stage which runs in reverse. You could then use the video's ended event to toggle the source back and forward between the forward and reversed videos.
Or as Ken, has helpfully suggested in the comments, create a single video in which the sequence is played forward and then in reverse. You can then set the video to loop and you've got what you're after.
Just for your reference, the w3 have quite a handy example which allows you to explore in real time the various methods, properties and events available in HTML5 video.
There is a program at enounce.com that it will increase the play speed of a video in a browser. I think that 95% of videos on the internet run on flash therefore this tool can be useful. I am wondering how that program was created. Maybe they modify the html source in the browser? perhaps it looks for the swf video playing on your browser and it injects some JavaScript on that html element to increase the speed. I been researching on Google and I think it is possible to alter the playback speed of a video with JavaScript. If it is not modifying the html page then it will be nice to at least know how this can be achieved. Also if a video plays on your browser it has to be saved somewhere in your computer I believe. That's why you can seek back and forth once the video finished downloading. why is it that it is almost impossible to find it and the only way of getting that video will be by capturing the packages with a package sniffer? anyways that is not my question I am just really curious on how that program achieves doing what it does. it speeds up everything even Pandora songs.
MySpeed seems to intercept the media stream coming from the server into the Flash player that sits in your browser. It changes the speed on the fly, and sends the result to the Flash player.
PS: If you need to control the playing speed of your own videos I recommend looking into the VLC Browser Plug-in, or the QuickTime player, which also has very good speed control features (from Javascript). Or you could use the HTML5 <video> tag.
Afaik, Flash-based players like Longtail/JWPlayer and Nonverbla don't have very good support for this.
I'm building a video for my website with HTML5. Ideally, I'd have only one silent video file, and five different audio tracks in different languages that sync up with the video.
Then I'd have a button that allows users to switch between audio tracks, even as the video is playing; and the correct audio track would come to life (without the video pausing or starting over or anything; much like a DVD audio track selection).
I can do this quite simply in Flash, but I don't want to. There has to be a way to do this in pure HTML5 or HTML5+jQuery. I'm thinking you'd play all the audio files at 0 volume, and only increase the volume of the active track... but I don't know how to even do that, let alone handle it when the user pauses or rewinds the video...
Thanks in advance!
Synchronization between audio and video is far more complex than simply starting the audio and video at the same time. Sound cards will playback at slightly different rates. (What is 44.1 kHz to me, might actually be 44.095 kHz to you.)
Often, the video is synchronized to the audio stream, but the player is what handles this. By loading up multiple objects for playback, you are effectively pulling them out of sync.
The only way this is going to work is if you can find a way to control the different audio streams from the video player. I don't know if this is possible.
Instead, I propose that you encode the video multiple times, with the different streams. You can use FFMPEG for this, and even automate the process, depending on your workflow. Switching among streams becomes a problem, but most video players are robust enough to guess the byte offset in the file, when given the bitrate.
If you only needed two languages, you could simply adjust the balance between a left and right stereo audio channel.
If you're willing to let all five tracks download, why not just mux them into the video? Videos are not limited to a single audio track (even AVI could do multiple audio tracks). Then syncing should be handled for you. You'd just enable/disable the audio tracks as needed.
It is doable with Web Audio API.
Part of my program listens to video element events and stops or restarts audio tracks created using web audio API. This gives me an ability to turn on and off any of the tracks in perfect sync.
There are some drawbacks.
There is no Web Audio API support in Internet Explorers except for Edge.
The technique works with buffered audio only and that's limiting. There are some problems with large files: https://bugs.chromium.org/p/chromium/issues/detail?id=71704