ffmpeg-stream
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0.7.0 • Public • Published

FFmpeg-Stream

Travis Codecov npm

Node bindings to ffmpeg command, exposing stream based API.

CHANGELOG

Note: ffmpeg must be installed and available in PATH.

Examples

const { Converter } = require("ffmpeg-stream")
const { createReadStream, createWriteStream } = require("fs")
 
async function convert() {
  const converter = new Converter()
 
  // get a writable input stream and pipe an image file to it
  const input = converter.createInputStream({
    f: "image2pipe",
    vcodec: "mjpeg",
  })
  createReadStream(`${__dirname}/cat.jpg`).pipe(input)
 
  // create an output stream, crop/scale image, save to file via node stream
  converter
    .createOutputStream({
      f: "image2",
      vcodec: "mjpeg",
      vf: "crop=300:300,scale=100:100",
    })
    .pipe(createWriteStream(`${__dirname}/cat_thumb.jpg`))
 
  // same, but save to file directly from ffmpeg
  converter.createOutputToFile(`${__dirname}/cat_full.jpg`, {
    vf: "crop=300:300",
  })
 
  // start processing
  await converter.run()
}

API

  • class Converter

    Creates a new instance of the ffmpeg converter class. Converting won't start until run() method is called.

    • method createInputStream(options: Options): stream.Writable

      Defines an ffmpeg input stream. Remember to specify the f option, which specifies the format of the input data. The returned stream is a writable stream.

    • method createInputFromFile(file: string, options: Options): void

      Defines an ffmpeg input using specified path. This is the same as specifying an input on the command line.

    • method createBufferedInputStream(options: Options): stream.Writable

      This is a mix of createInputStream and createInputFromFile. It creates a temporary file and instructs ffmpeg to use it, then it returns a writable stream attached to that file. Using this method will cause a huge delay.

    • method createOutputStream(options: Options): stream.Readable

      Defines an ffmpeg output stream. Remember to specify the f option, which specifies the format of the output data. The returned stream is a readable stream.

    • method createOutputToFile(file: string, options: Options): void

      Defines an ffmpeg output using specified path. This is the same as specifying an output on the command line.

    • method createBufferedOutputStream(options: Options): stream.Readable

      This is a mix of createOutputStream and createOutputToFile. It creates a temporary file and instructs ffmpeg to use it, then it returns a readable stream attached to that file. Using this method will cause a huge delay.

    • method input(file?: string, options: Options): stream.Writable | undefined

      DEPRECATED! Use one of 3 input methods above.

      This is the same as createInputFromFile when the file is specified, and createInputStream when it isn't, or createBufferedInputStream when also a magic option buffer is set to true.

    • method output(file?: string, options: Options): stream.Readable | undefined

      DEPRECATED! Use one of the 3 output methods above.

      This is the same as createOutputFromFile when the file is specified, and createOutputStream when it isn't, or createBufferedOutputStream when also a magic option buffer is set to true.

    • method run(): Promise<void>

      Starts the ffmpeg process. Returns a Promise which resolves on normal exit or kill, but rejects on ffmpeg error.

    • method kill(): void

      Kills the ffmpeg process.

  • type Options

    Object of options which you normally pass to the ffmpeg command in the terminal. Documentation for individual options can be found at ffmpeg site in audio and video category. For boolean options specify true or false. If you'd like to specify the same argument multiple times you can do so by providing an array of values. E.g. { map: ["0:v", "1:a"] }

FAQ

How to get video duration and other stats

You can use ffprobe command for now. It might be implemented in the library in the future, though.

Is there a progress or onFrameEmitted event

Currently, no.

Error: Muxer does not support non seekable output

When getting error similar to this:

  [mp4 @ 0000000000e4db00] muxer does not support non seekable output
  Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument
  Error initializing output stream 0:1 --
  encoded 0 frames
  Conversion failed!

    at ChildProcess.<anonymous> (<DirPath>\node_modules\ffmpeg-stream\lib\index.js:215:27)
    at emitTwo (events.js:106:13)
    at ChildProcess.emit (events.js:191:7)
    at Process.ChildProcess._handle.onexit (internal/child_process.js:215:12)

ffmpeg says that the combination of options you specified doesn't support streaming. You can experiment with calling ffmpeg directly and specifying - as output file. Maybe some other options or different format will work. Streaming sequence of JPEGs over websockets worked flawlessly for me (f: 'mjpeg').

You can also use createBufferedOutputStream. That tells the library to save output to a temporary file and then create a node stream from that file. It wont start producing data until the conversion is complete, though.

How to get individual frame data

You have to set output format to mjpeg and then split the stream manually by looking at the bytes. You can implement a transform stream which does this:

const { Transform } = require("stream")
 
class ExtractFrames extends Transform {
  constructor(delimiter) {
    super({ readableObjectMode: true })
    this.delimiter = Buffer.from(delimiter, "hex")
    this.buffer = Buffer.alloc(0)
  }
 
  _transform(data, enc, cb) {
    // Add new data to buffer
    this.buffer = Buffer.concat([this.buffer, data])
    while (true) {
      const start = this.buffer.indexOf(this.delimiter)
      if (start < 0) break // there's no frame data at all
      const end = this.buffer.indexOf(this.delimiter, start + this.delimiter.length)
      if (end < 0) break // we haven't got the whole frame yet
      this.push(this.buffer.slice(start, end)) // emit a frame
      this.buffer = this.buffer.slice(end) // remove frame data from buffer
      if (start > 0) console.error(`Discarded ${start} bytes of invalid data`)
    }
    cb()
  }
}

And then use it like that:

const { Converter } = require("ffmpeg-stream")
 
const converter = new Converter()
 
converter
  .createOutputStream({ f: "image2pipe", vcodec: "mjpeg" })
  .pipe(new ExtractFrames("FFD8FF")) // use jpg magic number as delimiter
  .on("data", frame => {
    /* do things with frame (instance of Buffer) */
  })
  .on("end", () => {
    /* do things on complete */
  })
  .on("error", () => {
    /* do things on error */
  })

How to create an animation from a set of image files

I have images in Amazon S3 bucket (private) so I'm using their SDK to download those. I get the files in Buffer objects. Is there any way I can use your package to create a video out of it?

So far I've been downloading the files and then using the following command: ffmpeg -framerate 30 -pattern_type glob -i '*.jpg' -c:v libx264 -pix_fmt yuv420p out.mp4

But now want to do it from my node js application automatically.

const { Converter } = require("ffmpeg-stream")
 
const frames = ["frame1.jpg", "frame2.jpg", ...etc]
 
const converter = new Converter() // create converter
 
// create input writable stream
const input = converter.createInputStream({ f: "image2pipe", r: 30 })
// output to file
converter.createOutputToFile("out.mp4", {
  vcodec: "libx264",
  pix_fmt: "yuv420p",
})
 
// for every frame create a function that returns a promise
frames
  .map(filename => () =>
    new Promise((resolve, reject) =>
      s3
        .getObject({ Bucket: "...", Key: filename })
        .createReadStream()
        .on("end", resolve)
        .on("error", reject)
        // pipe to converter, but don't end the input yet
        .pipe(input, { end: false })
    )
  )
  // reduce into a single promise, run sequentially
  .reduce((prev, next) => prev.then(next), Promise.resolve())
  // end converter input
  .then(() => input.end())
 
converter.run()

How to stream a video when there's data, otherwise an intermission image

You can turn your main stream into series of jpeg images with output format mjpeg and combine it with static image by repeatedly piping a single jpeg image when there's no data from main stream. Then pipe it to second ffmpeg process which combines jpeg images into video.

const fs = require("fs")
const { Converter } = require("ffmpeg-stream")
 
// the combining ffmpeg process
const combine = new Converter()
const combineInput = combine.createInputStream({ f: "mjpeg" })
 
// remember if we are streaming currently
let streaming = false
 
// argument should be a WebM video stream
function streamVideo(stream) {
  streaming = true
 
  // the splitting ffmpeg process
  const split = new Converter()
 
  // pipe video to splitting process
  stream.pipe(split.createInputStream({ f: "webm" }))
 
  // get jpegs and pipe them to combining process
  split.createOutputStream({ f: "mjpeg" }).pipe(combineInput, { end: false })
 
  stream.on("end", () => {
    // video stream ended
    streaming = false
  })
 
  split.run()
}
 
setInterval(() => {
  // if we are streaming - do nothing
  if (streaming) return
 
  // pipe a single jpeg file 30 times per second
  // into the combining process
  fs.createReadStream("intermission_pic.jpg").pipe(combineInput, { end: false })
}, 1000 / 30)
 
// the final output
combine.createOutputStream({ f: "whatever format you want" }).pipe(/* wherever you want */)
 
combine.run()

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npm i ffmpeg-stream

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0.7.0

License

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