Ngs2CalcWaveformBlock returned NGS2_ERROR_UNKNOWN_WAVEFORM_FORMAT with a
zeroed block for 16-bit PCM (0x12). The Binding of Isaac: Repentance
(PPSA03311) ignores the error and queues the zeroed blocks, which the
sampler skips, so the game had no audio at all. PCM frames have a fixed
size, so the block now starts at sample_pos frames and spans num_samples
frames.
Fixes#667
Co-authored-by: gl-ungus <notasecondemail63@gmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
