Not an issue - Looking for an example of writing encoded Opus data to a file

I have opus encoded bytes and I’d like to write them to an opus file; since the only example I found uses an existing opus file to read from then write to a new file, it doesn’t fit my need. I don’t have a source file, I am taking pcm samples and encoding them with an Opus encoder, so I tried to do this and it didn’t work:

    OggPacket pkt = new OggPacket((byte[]) outBuf.getData());
    OpusAudioData oad = new OpusAudioData(pkt);
    opusFile.writeAudioData(oad);

As well as this

    OpusAudioData oad = new OpusAudioData((byte[]) outBuf.getData());
    opusFile.writeAudioData(oad);

When I tried using the OggPacket, I get this exception:

java.lang.NullPointerException: null
	at org.gagravarr.ogg.OggPacket.getGranulePosition(OggPacket.java:74)
	at org.gagravarr.ogg.OggStreamAudioVisualData.<init>(OggStreamAudioVisualData.java:28)
	at org.gagravarr.ogg.OggStreamAudioData.<init>(OggStreamAudioData.java:21)
	at org.gagravarr.opus.OpusAudioData.<init>(OpusAudioData.java:29)

My file creation looks like so:

        Path opus = Paths.get("target/test-classes/out.opus");
        // clean up existing output files
        try {
            Files.deleteIfExists(opus);
        } catch (IOException e1) {
        }
        OpusFile opusFile = null;
        try {
            // set opus out
            OpusTags ot = new OpusTags();
            OpusInfo oi = new OpusInfo();
            oi.setSampleRate(48000);
            oi.setNumChannels(2);
            //oi.preSkip = 3840
            opusFile = new OpusFile(new FileOutputStream(opus.toFile()), oi, ot);

Any examples or clues as to how to accomplish what I need would be greatly appretiated.

[mondain]

@andrm I pulled the PR https://github.com/Gagravarr/VorbisJava/pull/33 into my fork and the granule warnings disappeared and the duration is exactly correct now in ffprobe and opustool Playback length: 00:01:00.00

[andrm]

@mondain Please see https://tools.ietf.org/html/rfc7845.html on how to calculate granule position and pre-skip.

core/src/main/java/org/gagravarr/opus/OpusStatistics.java has also instructive code, you see where the errors are coming from.