fix-webm-duration
navigator.mediaDevices.getUserMedia
+ MediaRecorder
create WEBM files without duration metadata.
This library appends missing metadata section right to the file blob.
Usage
The library contains only one script fix-webm-duration.js
and has no dependencies.
Syntax:
ysFixWebmDuration(blob, duration, callback = undefined, options = {});
where
blob
is Blob
object with file contents from MediaRecorder
duration
is video duration in milliseconds (you should calculate it while recording the video)callback
is callback function that will receive fixed blob.
If omitted, a Promise
object will be returned instead.options
is an object of options:
options.logger
- a callback for logging debug messages or false
.
The callback should accept one argument - the message string.
By default, console.log
will be used for logging.
Passing false
will disable the logging.
ysFixWebmDuration
will parse and fix your file asynchronously and will call your callback once the result is ready.
If the original blob already contains duration metadata section and the duration value is not empty, the callback will receive it without any changes made.
Example:
var mediaRecorder;
var mediaParts;
var startTime;
function startRecording(stream, options) {
mediaParts = [];
mediaRecorder = new MediaRecorder(stream, options);
mediaRecorder.onstop = function() {
var duration = Date.now() - startTime;
var buggyBlob = new Blob(mediaParts, { type: 'video/webm' });
ysFixWebmDuration(buggyBlob, duration, function(fixedBlob) {
displayResult(fixedBlob);
});
ysFixWebmDuration(buggyBlob, duration, {logger: false})
.then(function(fixedBlob) {
displayResult(fixedBlob);
});
};
mediaRecorder.ondataavailable = function(event) {
var data = event.data;
if (data && data.size > 0) {
mediaParts.push(data);
}
};
mediaRecorder.start();
startTime = Date.now();
}
function stopRecording() {
mediaRecorder.stop();
}
function displayResult(blob) {
}
Note: this example is not a MediaRecorder
usage guide.