konowebcodecs/apps/website/docs/getting-started/usage.md
2023-07-26 00:23:09 +08:00

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# Usage
Learn the basics of using ffmpeg.wasm.
:::note
It is recommended to read [overview](/docs/overview) first.
:::
## Transcoding AVI video to MP4 video
:::tip
`Load ffmpeg-core` might take a few minutes to complete as it downloads
a ~31 MB ffmpeg-core.wasm.
:::
```jsx live
function() {
const [loaded, setLoaded] = useState(false);
const ffmpegRef = useRef(new FFmpeg());
const videoRef = useRef(null);
const messageRef = useRef(null);
const load = async () => {
const ffmpeg = ffmpegRef.current;
ffmpeg.on("log", ({ message }) => {
messageRef.current.innerHTML = message;
});
await ffmpeg.load();
setLoaded(true);
}
const transcode = async () => {
const ffmpeg = ffmpegRef.current;
await ffmpeg.writeFile(
"input.avi",
await fetchFile('/video/video-15s.avi')
);
await ffmpeg.exec(['-i', 'input.avi', 'output.mp4']);
const data = await ffmpeg.readFile('output.mp4');
videoRef.current.src =
URL.createObjectURL(new Blob([data.buffer], {type: 'video/mp4'}));
}
return (loaded
? (
<>
<video ref={videoRef} controls></video><br/>
<button onClick={transcode}>Transcode avi to mp4</button>
<p ref={messageRef}></p>
</>
)
: (
<button onClick={load}>Load ffmpeg-core</button>
)
);
}
```
## Transcoding AVI video to MP4 video (multi-thread)
:::tip
`Load ffmpeg-core` might take a few minutes to complete as it downloads
a ~31 MB ffmpeg-core.wasm.
:::
```jsx live
function() {
const [loaded, setLoaded] = useState(false);
const ffmpegRef = useRef(new FFmpeg());
const videoRef = useRef(null);
const messageRef = useRef(null);
const load = async () => {
const baseURL = 'https://unpkg.com/@ffmpeg/core-mt@0.12.0-alpha.2/dist/umd'
const ffmpeg = ffmpegRef.current;
ffmpeg.on("log", ({ message }) => {
messageRef.current.innerHTML = message;
});
await ffmpeg.load({
coreURL: await toBlobURL(`${baseURL}/ffmpeg-core.js`),
wasmURL: await toBlobURL(`${baseURL}/ffmpeg-core.wasm`),
workerURL: await toBlobURL(`${baseURL}/ffmpeg-core.worker.js`),
thread: true,
});
setLoaded(true);
}
const transcode = async () => {
const ffmpeg = ffmpegRef.current;
await ffmpeg.writeFile(
"input.avi",
await fetchFile('/video/video-15s.avi')
);
await ffmpeg.exec(['-i', 'input.avi', 'output.mp4']);
const data = await ffmpeg.readFile('output.mp4');
videoRef.current.src =
URL.createObjectURL(new Blob([data.buffer], {type: 'video/mp4'}));
}
return (loaded
? (
<>
<video ref={videoRef} controls></video><br/>
<button onClick={transcode}>Transcode avi to mp4</button>
<p ref={messageRef}></p>
</>
)
: (
<button onClick={load}>Load ffmpeg-core</button>
)
);
}
```