Ogg Vorbis random noises in decoded audio

[Zokhoi]

In my use case I have a bunch of ogg files, some of them decode to have random noises throughout the audio, while also having the decoded audio shorter than expected.

Upper: audio decoded with the ogg vorbis decoder
Lower: ogg file imported into Audacity directly

Here is the offending source audio file used for the example screenshot.

Code to produce the decoded audio:

import fs from "fs";
import path from "path";
import { OggVorbisDecoder } from "@wasm-audio-decoders/ogg-vorbis";
import wav from "node-wav";

/** Reads filename from command line input */
let filename = process.argv[2];
let dir = path.dirname(path.resolve(filename));

!(async ()=>{  
  let decoder = new OggVorbisDecoder();
  await decoder.ready;

  let fileBuf = fs.readFileSync(filename);
  let audio = await decoder.decodeFile(fileBuf);

  let buf = wav.encode(audio.channelData, {
    sampleRate: audio.sampleRate,
    float: true,
    bitDepth: audio.bitDepth,
  });
  fs.writeFileSync(path.resolve(dir, `test.wav`), buf);

  decoder.free();
})()

All ogg files in my collection should have been generated by the same encoder, because the collection was a pack of samples making up one entire song. However, only some of the files have this issue. The whole pack is available here (google drive).

[eshaz]

Thanks for posting this. I'll take a look. Which encoder are you using to write the Ogg Vorbis files?

[Zokhoi]

I didn't make the ogg files so I don't know the encoder for them. For saving the wave files in the sample code it was node-wav.

[eshaz]

I found the issue for this. There is a bug in the codec-parser Ogg parsing where if there are two continued packets in a row, the previous data is not appended. The else if condition below should be moved to an if condition above it, so the previous packet data is saved. I'll get a release published for codec-parser and all the other libraries that rely on it published here soon.

https://github.com/eshaz/codec-parser/blob/master/src/containers/ogg/OggParser.js#L129-L145

This could happen to any codec using Ogg, but it doesn't seem very common to have a bunch of continued packets in a row like in the example you provided. It's still valid Ogg Vorbis, just unusual. Thanks for reporting this and providing a good example.

[eshaz]

I just published a new release of @wasm-audio-decoders/ogg-vorbis. Testing locally worked just fine and looked just like your screenshot in Audacity. Let me know if something still isn't working.