30 KiB
id | title | sidebar_label | sidebar_position | custom_edit_url |
---|---|---|---|---|
FFmpeg | Class: FFmpeg | FFmpeg | 0 | null |
Provides APIs to interact with ffmpeg web worker.
Example
const ffmpeg = new FFmpeg();
Hierarchy
-
EventEmitter
↳
FFmpeg
Constructors
constructor
• new FFmpeg()
Defined in
packages/ffmpeg/src/classes.ts:99
Properties
#rejects
• Private
#rejects: Callbacks
= {}
Defined in
packages/ffmpeg/src/classes.ts:95
#resolves
• Private
#resolves: Callbacks
= {}
#resolves and #rejects tracks Promise resolves and rejects to be called when we receive message from web worker.
Defined in
packages/ffmpeg/src/classes.ts:94
#worker
• Private
#worker: null
| Worker
= null
Defined in
packages/ffmpeg/src/classes.ts:88
loaded
• loaded: boolean
= false
Defined in
packages/ffmpeg/src/classes.ts:97
captureRejectionSymbol
▪ Static
Readonly
captureRejectionSymbol: typeof captureRejectionSymbol
Defined in
node_modules/@types/node/events.d.ts:291
captureRejections
▪ Static
captureRejections: boolean
Sets or gets the default captureRejection value for all emitters.
Defined in
node_modules/@types/node/events.d.ts:296
defaultMaxListeners
▪ Static
defaultMaxListeners: number
Defined in
node_modules/@types/node/events.d.ts:297
errorMonitor
▪ Static
Readonly
errorMonitor: typeof errorMonitor
This symbol shall be used to install a listener for only monitoring 'error'
events. Listeners installed using this symbol are called before the regular
'error'
listeners are called.
Installing a listener using this symbol does not change the behavior once an
'error'
event is emitted, therefore the process will still crash if no
regular 'error'
listener is installed.
Defined in
node_modules/@types/node/events.d.ts:290
Events
DOWNLOAD
▪ Static
Readonly
DOWNLOAD: "download"
Defined in
packages/ffmpeg/src/classes.ts:84
LOG
▪ Static
Readonly
LOG: "log"
Defined in
packages/ffmpeg/src/classes.ts:85
PROGRESS
▪ Static
Readonly
PROGRESS: "progress"
Defined in
packages/ffmpeg/src/classes.ts:86
Event Methods
on
▸ on(event
, listener
): FFmpeg
Listen to download progress events from ffmpeg.load()
.
Example
ffmpeg.on(FFmpeg.DOWNLOAD, ({ url, total, received, delta, done }) => {
// ...
})
Parameters
Name | Type |
---|---|
event |
"download" |
listener |
(data : DownloadProgressEvent ) => void |
Returns
Defined in
packages/ffmpeg/src/classes.ts:33
▸ on(event
, listener
): FFmpeg
Listen to log events from ffmpeg.exec()
.
Example
ffmpeg.on(FFmpeg.LOG, ({ message }) => {
// ...
})
Remarks
log includes output to stdout and stderr.
Parameters
Name | Type |
---|---|
event |
"log" |
listener |
(log : LogEvent ) => void |
Returns
Defined in
packages/ffmpeg/src/classes.ts:52
▸ on(event
, listener
): FFmpeg
Listen to progress events from ffmpeg.exec()
.
Example
ffmpeg.on(FFmpeg.PROGRESS, ({ progress }) => {
// ...
})
Remarks
The progress events are accurate only when the length of input and output video/audio file are the same.
Parameters
Name | Type |
---|---|
event |
"progress" |
listener |
(progress : Progress ) => void |
Returns
Defined in
packages/ffmpeg/src/classes.ts:69
FFmpeg Methods
exec
▸ exec(args
, timeout?
): Promise
<number
>
Execute ffmpeg command.
Remarks
To avoid common I/O issues, ["-nostdin", "-y"] are prepended to the args by default.
Example
const ffmpeg = new FFmpeg();
await ffmpeg.load();
await ffmpeg.writeFile("video.avi", ...);
// ffmpeg -i video.avi video.mp4
await ffmpeg.exec(["-i", "video.avi", "video.mp4"]);
const data = ffmpeg.readFile("video.mp4");
Parameters
Name | Type | Default value | Description |
---|---|---|---|
args |
string [] |
undefined |
ffmpeg command line args |
timeout |
number |
-1 |
milliseconds to wait before stopping the command execution. Default Value -1 |
Returns
Promise
<number
>
0
if no error, != 0
if timeout (1) or error.
Defined in
packages/ffmpeg/src/classes.ts:202
load
▸ load(config?
): Promise
<boolean
>
Loads ffmpeg-core inside web worker. It is required to call this method first as it initializes WebAssembly and other essential variables.
Parameters
Name | Type |
---|---|
config |
FFMessageLoadConfig |
Returns
Promise
<boolean
>
true
if ffmpeg core is loaded for the first time.
Defined in
packages/ffmpeg/src/classes.ts:171
terminate
▸ terminate(): void
Terminate all ongoing API calls and terminate web worker.
FFmpeg.load()
must be called again before calling any other APIs.
Returns
void
Defined in
packages/ffmpeg/src/classes.ts:223
File System Methods
createDir
▸ createDir(path
): Promise
<boolean
>
Create a directory.
Parameters
Name | Type |
---|---|
path |
string |
Returns
Promise
<boolean
>
Defined in
packages/ffmpeg/src/classes.ts:321
deleteDir
▸ deleteDir(path
): Promise
<boolean
>
Delete an empty directory.
Parameters
Name | Type |
---|---|
path |
string |
Returns
Promise
<boolean
>
Defined in
packages/ffmpeg/src/classes.ts:343
deleteFile
▸ deleteFile(path
): Promise
<boolean
>
Delete a file.
Parameters
Name | Type |
---|---|
path |
string |
Returns
Promise
<boolean
>
Defined in
packages/ffmpeg/src/classes.ts:299
listDir
▸ listDir(path
): Promise
<FSNode
[]>
List directory contents.
Parameters
Name | Type |
---|---|
path |
string |
Returns
Promise
<FSNode
[]>
Defined in
packages/ffmpeg/src/classes.ts:332
readFile
▸ readFile(path
, encoding?
): Promise
<FileData
>
Read data from ffmpeg.wasm.
Example
const ffmpeg = new FFmpeg();
await ffmpeg.load();
const data = await ffmpeg.readFile("video.mp4");
Parameters
Name | Type | Default value | Description |
---|---|---|---|
path |
string |
undefined |
- |
encoding |
string |
"binary" |
File content encoding, supports two encodings: - utf8: read file as text file, return data in string type. - binary: read file as binary file, return data in Uint8Array type. Default Value binary |
Returns
Promise
<FileData
>
Defined in
packages/ffmpeg/src/classes.ts:278
rename
▸ rename(oldPath
, newPath
): Promise
<boolean
>
Rename a file or directory.
Parameters
Name | Type |
---|---|
oldPath |
string |
newPath |
string |
Returns
Promise
<boolean
>
Defined in
packages/ffmpeg/src/classes.ts:310
writeFile
▸ writeFile(path
, data
): Promise
<boolean
>
Write data to ffmpeg.wasm.
Example
const ffmpeg = new FFmpeg();
await ffmpeg.load();
await ffmpeg.writeFile("video.avi", await fetchFile("../video.avi"));
await ffmpeg.writeFile("text.txt", "hello world");
Parameters
Name | Type |
---|---|
path |
string |
data |
FileData |
Returns
Promise
<boolean
>
Defined in
packages/ffmpeg/src/classes.ts:252
Other Methods
#registerHandlers
▸ Private
#registerHandlers(): void
register worker message event handlers.
Returns
void
Defined in
packages/ffmpeg/src/classes.ts:106
#send
▸ Private
#send(__namedParameters
, trans?
): Promise
<CallbackData
>
Generic function to send messages to web worker.
Parameters
Name | Type | Default value |
---|---|---|
__namedParameters |
Message |
undefined |
trans |
Transferable [] |
[] |
Returns
Promise
<CallbackData
>
Defined in
packages/ffmpeg/src/classes.ts:148
addListener
▸ addListener(eventName
, listener
): FFmpeg
Alias for emitter.on(eventName, listener)
.
Since
v0.1.26
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
listener |
(...args : any []) => void |
Returns
Defined in
node_modules/@types/node/events.d.ts:317
emit
▸ emit(eventName
, ...args
): boolean
Synchronously calls each of the listeners registered for the event namedeventName
, in the order they were registered, passing the supplied arguments
to each.
Returns true
if the event had listeners, false
otherwise.
const EventEmitter = require('events');
const myEmitter = new EventEmitter();
// First listener
myEmitter.on('event', function firstListener() {
console.log('Helloooo! first listener');
});
// Second listener
myEmitter.on('event', function secondListener(arg1, arg2) {
console.log(`event with parameters ${arg1}, ${arg2} in second listener`);
});
// Third listener
myEmitter.on('event', function thirdListener(...args) {
const parameters = args.join(', ');
console.log(`event with parameters ${parameters} in third listener`);
});
console.log(myEmitter.listeners('event'));
myEmitter.emit('event', 1, 2, 3, 4, 5);
// Prints:
// [
// [Function: firstListener],
// [Function: secondListener],
// [Function: thirdListener]
// ]
// Helloooo! first listener
// event with parameters 1, 2 in second listener
// event with parameters 1, 2, 3, 4, 5 in third listener
Since
v0.1.26
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
...args |
any [] |
Returns
boolean
Defined in
node_modules/@types/node/events.d.ts:573
eventNames
▸ eventNames(): (string
| symbol
)[]
Returns an array listing the events for which the emitter has registered
listeners. The values in the array are strings or Symbol
s.
const EventEmitter = require('events');
const myEE = new EventEmitter();
myEE.on('foo', () => {});
myEE.on('bar', () => {});
const sym = Symbol('symbol');
myEE.on(sym, () => {});
console.log(myEE.eventNames());
// Prints: [ 'foo', 'bar', Symbol(symbol) ]
Since
v6.0.0
Returns
(string
| symbol
)[]
Defined in
node_modules/@types/node/events.d.ts:632
getMaxListeners
▸ getMaxListeners(): number
Returns the current max listener value for the EventEmitter
which is either
set by emitter.setMaxListeners(n)
or defaults to defaultMaxListeners.
Since
v1.0.0
Returns
number
Defined in
node_modules/@types/node/events.d.ts:489
listenerCount
▸ listenerCount(eventName
): number
Returns the number of listeners listening to the event named eventName
.
Since
v3.2.0
Parameters
Name | Type | Description |
---|---|---|
eventName |
string | symbol |
The name of the event being listened for |
Returns
number
Defined in
node_modules/@types/node/events.d.ts:579
listeners
▸ listeners(eventName
): Function
[]
Returns a copy of the array of listeners for the event named eventName
.
server.on('connection', (stream) => {
console.log('someone connected!');
});
console.log(util.inspect(server.listeners('connection')));
// Prints: [ [Function] ]
Since
v0.1.26
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
Returns
Function
[]
Defined in
node_modules/@types/node/events.d.ts:502
off
▸ off(eventName
, listener
): FFmpeg
Alias for emitter.removeListener()
.
Since
v10.0.0
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
listener |
(...args : any []) => void |
Returns
Defined in
node_modules/@types/node/events.d.ts:462
once
▸ once(eventName
, listener
): FFmpeg
Adds a one-timelistener
function for the event named eventName
. The
next time eventName
is triggered, this listener is removed and then invoked.
server.once('connection', (stream) => {
console.log('Ah, we have our first user!');
});
Returns a reference to the EventEmitter
, so that calls can be chained.
By default, event listeners are invoked in the order they are added. Theemitter.prependOnceListener()
method can be used as an alternative to add the
event listener to the beginning of the listeners array.
const myEE = new EventEmitter();
myEE.once('foo', () => console.log('a'));
myEE.prependOnceListener('foo', () => console.log('b'));
myEE.emit('foo');
// Prints:
// b
// a
Since
v0.3.0
Parameters
Name | Type | Description |
---|---|---|
eventName |
string | symbol |
The name of the event. |
listener |
(...args : any []) => void |
The callback function |
Returns
Defined in
node_modules/@types/node/events.d.ts:377
prependListener
▸ prependListener(eventName
, listener
): FFmpeg
Adds the listener
function to the beginning of the listeners array for the
event named eventName
. No checks are made to see if the listener
has
already been added. Multiple calls passing the same combination of eventName
and listener
will result in the listener
being added, and called, multiple
times.
server.prependListener('connection', (stream) => {
console.log('someone connected!');
});
Returns a reference to the EventEmitter
, so that calls can be chained.
Since
v6.0.0
Parameters
Name | Type | Description |
---|---|---|
eventName |
string | symbol |
The name of the event. |
listener |
(...args : any []) => void |
The callback function |
Returns
Defined in
node_modules/@types/node/events.d.ts:597
prependOnceListener
▸ prependOnceListener(eventName
, listener
): FFmpeg
Adds a one-timelistener
function for the event named eventName
to the beginning of the listeners array. The next time eventName
is triggered, this
listener is removed, and then invoked.
server.prependOnceListener('connection', (stream) => {
console.log('Ah, we have our first user!');
});
Returns a reference to the EventEmitter
, so that calls can be chained.
Since
v6.0.0
Parameters
Name | Type | Description |
---|---|---|
eventName |
string | symbol |
The name of the event. |
listener |
(...args : any []) => void |
The callback function |
Returns
Defined in
node_modules/@types/node/events.d.ts:613
rawListeners
▸ rawListeners(eventName
): Function
[]
Returns a copy of the array of listeners for the event named eventName
,
including any wrappers (such as those created by .once()
).
const emitter = new EventEmitter();
emitter.once('log', () => console.log('log once'));
// Returns a new Array with a function `onceWrapper` which has a property
// `listener` which contains the original listener bound above
const listeners = emitter.rawListeners('log');
const logFnWrapper = listeners[0];
// Logs "log once" to the console and does not unbind the `once` event
logFnWrapper.listener();
// Logs "log once" to the console and removes the listener
logFnWrapper();
emitter.on('log', () => console.log('log persistently'));
// Will return a new Array with a single function bound by `.on()` above
const newListeners = emitter.rawListeners('log');
// Logs "log persistently" twice
newListeners[0]();
emitter.emit('log');
Since
v9.4.0
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
Returns
Function
[]
Defined in
node_modules/@types/node/events.d.ts:532
removeAllListeners
▸ removeAllListeners(event?
): FFmpeg
Removes all listeners, or those of the specified eventName
.
It is bad practice to remove listeners added elsewhere in the code,
particularly when the EventEmitter
instance was created by some other
component or module (e.g. sockets or file streams).
Returns a reference to the EventEmitter
, so that calls can be chained.
Since
v0.1.26
Parameters
Name | Type |
---|---|
event? |
string | symbol |
Returns
Defined in
node_modules/@types/node/events.d.ts:473
removeListener
▸ removeListener(eventName
, listener
): FFmpeg
Removes the specified listener
from the listener array for the event namedeventName
.
const callback = (stream) => {
console.log('someone connected!');
};
server.on('connection', callback);
// ...
server.removeListener('connection', callback);
removeListener()
will remove, at most, one instance of a listener from the
listener array. If any single listener has been added multiple times to the
listener array for the specified eventName
, then removeListener()
must be
called multiple times to remove each instance.
Once an event is emitted, all listeners attached to it at the
time of emitting are called in order. This implies that anyremoveListener()
or removeAllListeners()
calls after emitting and before the last listener finishes execution
will not remove them fromemit()
in progress. Subsequent events behave as expected.
const myEmitter = new MyEmitter();
const callbackA = () => {
console.log('A');
myEmitter.removeListener('event', callbackB);
};
const callbackB = () => {
console.log('B');
};
myEmitter.on('event', callbackA);
myEmitter.on('event', callbackB);
// callbackA removes listener callbackB but it will still be called.
// Internal listener array at time of emit [callbackA, callbackB]
myEmitter.emit('event');
// Prints:
// A
// B
// callbackB is now removed.
// Internal listener array [callbackA]
myEmitter.emit('event');
// Prints:
// A
Because listeners are managed using an internal array, calling this will
change the position indices of any listener registered after the listener
being removed. This will not impact the order in which listeners are called,
but it means that any copies of the listener array as returned by
the emitter.listeners()
method will need to be recreated.
When a single function has been added as a handler multiple times for a single
event (as in the example below), removeListener()
will remove the most
recently added instance. In the example the once('ping')
listener is removed:
const ee = new EventEmitter();
function pong() {
console.log('pong');
}
ee.on('ping', pong);
ee.once('ping', pong);
ee.removeListener('ping', pong);
ee.emit('ping');
ee.emit('ping');
Returns a reference to the EventEmitter
, so that calls can be chained.
Since
v0.1.26
Parameters
Name | Type |
---|---|
eventName |
string | symbol |
listener |
(...args : any []) => void |
Returns
Defined in
node_modules/@types/node/events.d.ts:457
setMaxListeners
▸ setMaxListeners(n
): FFmpeg
By default EventEmitter
s will print a warning if more than 10
listeners are
added for a particular event. This is a useful default that helps finding
memory leaks. The emitter.setMaxListeners()
method allows the limit to be
modified for this specific EventEmitter
instance. The value can be set toInfinity
(or 0
) to indicate an unlimited number of listeners.
Returns a reference to the EventEmitter
, so that calls can be chained.
Since
v0.3.5
Parameters
Name | Type |
---|---|
n |
number |
Returns
Defined in
node_modules/@types/node/events.d.ts:483
getEventListeners
▸ Static
getEventListeners(emitter
, name
): Function
[]
Returns a copy of the array of listeners for the event named eventName
.
For EventEmitter
s this behaves exactly the same as calling .listeners
on
the emitter.
For EventTarget
s this is the only way to get the event listeners for the
event target. This is useful for debugging and diagnostic purposes.
const { getEventListeners, EventEmitter } = require('events');
{
const ee = new EventEmitter();
const listener = () => console.log('Events are fun');
ee.on('foo', listener);
getEventListeners(ee, 'foo'); // [listener]
}
{
const et = new EventTarget();
const listener = () => console.log('Events are fun');
et.addEventListener('foo', listener);
getEventListeners(et, 'foo'); // [listener]
}
Since
v15.2.0, v14.17.0
Parameters
Name | Type |
---|---|
emitter |
EventEmitter | DOMEventTarget |
name |
string | symbol |
Returns
Function
[]
Defined in
node_modules/@types/node/events.d.ts:262
listenerCount
▸ Static
listenerCount(emitter
, eventName
): number
A class method that returns the number of listeners for the given eventName
registered on the given emitter
.
const { EventEmitter, listenerCount } = require('events');
const myEmitter = new EventEmitter();
myEmitter.on('event', () => {});
myEmitter.on('event', () => {});
console.log(listenerCount(myEmitter, 'event'));
// Prints: 2
Since
v0.9.12
Deprecated
Since v3.2.0 - Use listenerCount
instead.
Parameters
Name | Type | Description |
---|---|---|
emitter |
EventEmitter |
The emitter to query |
eventName |
string | symbol |
The event name |
Returns
number
Defined in
node_modules/@types/node/events.d.ts:234
on
▸ Static
on(emitter
, eventName
, options?
): AsyncIterableIterator
<any
>
const { on, EventEmitter } = require('events');
(async () => {
const ee = new EventEmitter();
// Emit later on
process.nextTick(() => {
ee.emit('foo', 'bar');
ee.emit('foo', 42);
});
for await (const event of on(ee, 'foo')) {
// The execution of this inner block is synchronous and it
// processes one event at a time (even with await). Do not use
// if concurrent execution is required.
console.log(event); // prints ['bar'] [42]
}
// Unreachable here
})();
Returns an AsyncIterator
that iterates eventName
events. It will throw
if the EventEmitter
emits 'error'
. It removes all listeners when
exiting the loop. The value
returned by each iteration is an array
composed of the emitted event arguments.
An AbortSignal
can be used to cancel waiting on events:
const { on, EventEmitter } = require('events');
const ac = new AbortController();
(async () => {
const ee = new EventEmitter();
// Emit later on
process.nextTick(() => {
ee.emit('foo', 'bar');
ee.emit('foo', 42);
});
for await (const event of on(ee, 'foo', { signal: ac.signal })) {
// The execution of this inner block is synchronous and it
// processes one event at a time (even with await). Do not use
// if concurrent execution is required.
console.log(event); // prints ['bar'] [42]
}
// Unreachable here
})();
process.nextTick(() => ac.abort());
Since
v13.6.0, v12.16.0
Parameters
Name | Type | Description |
---|---|---|
emitter |
EventEmitter |
- |
eventName |
string |
The name of the event being listened for |
options? |
StaticEventEmitterOptions |
- |
Returns
AsyncIterableIterator
<any
>
that iterates eventName
events emitted by the emitter
Defined in
node_modules/@types/node/events.d.ts:217
once
▸ Static
once(emitter
, eventName
, options?
): Promise
<any
[]>
Creates a Promise
that is fulfilled when the EventEmitter
emits the given
event or that is rejected if the EventEmitter
emits 'error'
while waiting.
The Promise
will resolve with an array of all the arguments emitted to the
given event.
This method is intentionally generic and works with the web platform EventTarget interface, which has no special'error'
event
semantics and does not listen to the 'error'
event.
const { once, EventEmitter } = require('events');
async function run() {
const ee = new EventEmitter();
process.nextTick(() => {
ee.emit('myevent', 42);
});
const [value] = await once(ee, 'myevent');
console.log(value);
const err = new Error('kaboom');
process.nextTick(() => {
ee.emit('error', err);
});
try {
await once(ee, 'myevent');
} catch (err) {
console.log('error happened', err);
}
}
run();
The special handling of the 'error'
event is only used when events.once()
is used to wait for another event. If events.once()
is used to wait for the
'error'
event itself, then it is treated as any other kind of event without
special handling:
const { EventEmitter, once } = require('events');
const ee = new EventEmitter();
once(ee, 'error')
.then(([err]) => console.log('ok', err.message))
.catch((err) => console.log('error', err.message));
ee.emit('error', new Error('boom'));
// Prints: ok boom
An AbortSignal
can be used to cancel waiting for the event:
const { EventEmitter, once } = require('events');
const ee = new EventEmitter();
const ac = new AbortController();
async function foo(emitter, event, signal) {
try {
await once(emitter, event, { signal });
console.log('event emitted!');
} catch (error) {
if (error.name === 'AbortError') {
console.error('Waiting for the event was canceled!');
} else {
console.error('There was an error', error.message);
}
}
}
foo(ee, 'foo', ac.signal);
ac.abort(); // Abort waiting for the event
ee.emit('foo'); // Prints: Waiting for the event was canceled!
Since
v11.13.0, v10.16.0
Parameters
Name | Type |
---|---|
emitter |
NodeEventTarget |
eventName |
string | symbol |
options? |
StaticEventEmitterOptions |
Returns
Promise
<any
[]>
Defined in
node_modules/@types/node/events.d.ts:157
▸ Static
once(emitter
, eventName
, options?
): Promise
<any
[]>
Parameters
Name | Type |
---|---|
emitter |
DOMEventTarget |
eventName |
string |
options? |
StaticEventEmitterOptions |
Returns
Promise
<any
[]>
Defined in
node_modules/@types/node/events.d.ts:158
setMaxListeners
▸ Static
setMaxListeners(n?
, ...eventTargets
): void
const {
setMaxListeners,
EventEmitter
} = require('events');
const target = new EventTarget();
const emitter = new EventEmitter();
setMaxListeners(5, target, emitter);
Since
v15.4.0
Parameters
Name | Type | Description |
---|---|---|
n? |
number |
A non-negative number. The maximum number of listeners per EventTarget event. |
...eventTargets |
(EventEmitter | DOMEventTarget )[] |
- |
Returns
void
Defined in
node_modules/@types/node/events.d.ts:280