将视频 stream 转换为音频 stream 无效

Question

I'm extracting audio from a video using ffmeg-fluent library

Actually when I save the audio in local it works. I get an audio file with data.

ffmpeg(recordedVideoStrm)
  .outputOptions([
    "-vn", // Discard the video
    "-acodec pcm_s16le", // Set the audio codec
    "-ar 44100", // Set the audio sample rate
    "-ac 2", // Set the number of audio channels
  ])
  .output("mp3")
  .on("error", function (err) {
    console.log("An error occurred: " + err.message);
  })
  .on("end", function () {
    console.log("Audio extraction completed");
  })
  .save("output.wav");

But when I try to convert the video stream to audio stream in order to save the file in my azure blob storage I get an empty file with 0 octet size.

const audioStream = ffmpeg(recordedVideoStrm)
  .outputOptions([
    "-vn", // Discard the video
    "-acodec pcm_s16le", // Set the audio codec
    "-ar 44100", // Set the audio sample rate
    "-ac 2", // Set the number of audio channels
  ])
  .on("error", function (err) {
    console.log("An error occurred: " + err.message);
  })
  .on("end", function () {
    console.log("Audio extraction completed");
  })
  .pipe(); 

const stream = await blobClient.uploadStream(audioStream);

Answer 1

• Here I have a work around were, instead of using the fluent-ffmpeg to pipe the data in the stream, we can store the audio to a file and read the file as stream and then upload it.

• here, I am writing the audio data to a novideo.mp3 file and then uploading the file as a stream.

code:

var  writeStream = Stream.Writable();
ffmpeg({source:'newtest.mp4'})
    .noVideo()
    .saveToFile("novideo.mp4");
writeStream = fs.createReadStream('novideo.mp4');
await  blockblobclient.uploadStream(writeStream);

output:

• Also, if you want to use the pipe() function then I think you have to pass a writable stream to the function along with option. refer these NPM- DOCS for it