FyroxEngine/Fyrox · warning

error while setting decoder position

Error message

error while setting decoder position

What it means

For streaming sound buffers, set_playback_time seeks the underlying decoder to the requested time. If the decoder cannot seek (time_seek returns Err), the position is not applied and a warning is logged; playback position tracking still continues from the clamped value.

Solutions

1. Prefer loading the buffer as non-streaming (immutable) if seeking is required
2. Check the audio file is valid and its decoder supports seek
3. Clamp requested playback time within [0, duration] before building the source
4. Downgrade severity expectations: playback continues from current decoder position

Example fix

// before
let src = GenericSourceBuilder::new(buffer).with_play_time(desired_time).build()?;
// after
let time = desired_time.clamp(Duration::ZERO, buffer.duration());
let src = GenericSourceBuilder::new(buffer).with_play_time(time).build()?; // and consider non-streaming buffer if seek is essential

let t = requested.clamp(Duration::ZERO, buffer.duration());
// prefer non-streaming buffer when seek support matters
let buffer = SoundBuffer::from_file(path)?; // vs raw streaming

fn seekable(b: &SoundBuffer) -> bool { !matches!(b, SoundBuffer::Streaming(_)) }

When it happens

Trigger: Calling GenericSourceBuilder::build with a play time, or set_playback_time, on a streaming buffer whose decoder does not support seeking to that offset (or seek fails for format reasons).

Common situations: Streaming compressed audio (OGG/MP3) with decoders lacking full seek support; requesting a time beyond/near the buffer duration in edge cases; malformed audio files.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Zero duration buffer
• Malformed bus graph!
• Unable to initialize audio output device! Reason

AI-assisted analysis of FyroxEngine/Fyrox@76c91aad8e (2026-09-10). Data as JSON: /api/errors/a79446859f2f7a60. Report an issue: GitHub.

Appendix: source

Thrown at fyrox-sound/src/source.rs:474

            if let Some(buffer) = buffer.state().data() {
                return Duration::from_secs_f64(self.playback_pos / (buffer.sample_rate() as f64));
            }
        }

        Duration::from_secs(0)
    }

    /// Sets playback duration.
    pub fn set_playback_time(&mut self, time: Duration) {
        if let Some(buffer) = self.buffer.as_ref() {
            if let Some(buffer) = buffer.state().data() {
                if let SoundBuffer::Streaming(ref mut streaming) = *buffer {
                    // Make sure decoder is at right position.
                    if streaming
                        .time_seek(time.clamp(Duration::from_secs(0), streaming.duration()))
                        .is_err()
                    {
                        Log::warn("error while setting decoder position");
                    }
                }
                // Set absolute position first.
                self.playback_pos = (time.as_secs_f64() * buffer.sample_rate as f64)
                    .clamp(0.0, buffer.duration().as_secs_f64());
                // Then adjust buffer read position.
                self.buf_read_pos = match *buffer {
                    SoundBuffer::Streaming(ref mut streaming) => {
                        // Make sure to load correct data into buffer from decoder.
                        streaming.read_next_block();
                        // Streaming sources has different buffer read position because
                        // buffer contains only small portion of data.
                        self.playback_pos % (StreamingBuffer::STREAM_SAMPLE_COUNT as f64)
                    }
                    SoundBuffer::Generic(_) => self.playback_pos,
                };
                assert!(
                    self.buf_read_pos * (buffer.channel_count() as f64)

View on GitHub (pinned to 76c91aad8e)