CODEWITHSUNDEEP
javalibvlcvlcj
foolo
foolo

Reputation: 958

Extract audio data to memory using vlcj

I want to extract audio data to memory using vlcj (https://github.com/caprica/vlcj, version 4.2.0). I don't want to play the video on the same time, just extract the audio data, as fast as the performance allows.

Right now I'm using a workaround based on this: https://github.com/caprica/vlcj/blob/master/src/test/java/uk/co/caprica/vlcj/test/rip/RipAudioTest.java, i.e. output the data to a file first, and then read the file. While this solution is working, it's not optimal and it takes disk space.

Maybe the example above can be modified to direct the audio to a callback instead.

A second example is:

https://github.com/caprica/vlcj/blob/master/src/test/java/uk/co/caprica/vlcj/test/directaudio/DirectAudioPlayerTest.java

In that example, the audio data is extracted to memory, which is what I want. But it also plays the video in a window, which is not what I want. Maybe that example can be modified to turn off the video somehow, and make it run as fast as possible?

Upvotes: 3

Views: 230

Answers (1)

caprica
caprica

Reputation: 4146

There's no perfect answer here, sadly.

Using the DirectAudioPlayerTest.java that you found already, you can change the media player factory creation to pass this parameter to prevent the video window being opened:

factory = new MediaPlayerFactory("--novideo");

You will receive the audio into a memory buffer at the rate at which VLC decodes it, so if you have a 5 minute video it will take 5 minutes to extract the audio - not ideal.

This is the only way with vlcj that you can grab the audio data in memory.

The RipAudioTest.java that you found, IIRC, extracts the audio as quickly as possible, which may be a lot faster than the normal playback speed - but here you can't grab the decoded audio directly into your Java application.

So the solution you already have, ripping the track to disk first, might actually be the best solution you can achieve with vlcj here (since it could be considerably quicker than using the direct audio player).

Upvotes: 2

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