bug or feature by design when handle sdl callback?

[yexiangyu]

file: examples/common-sdl.cpp, line: 156

memcpy(&m_audio[0], &stream[n0], (n_samples - n0) * sizeof(float));

should change to

memcpy(&m_audio[0], &stream[n0 * sizeof(float)], (n_samples - n0) * sizeof(float));

https://github.com/ggerganov/whisper.cpp/blob/e2f0eba2d4dbe4ded5625cbd8a9c17e13f2482f6/examples/common-sdl.cpp#L156C1-L156C80

[bobqianic]

Indeed, you're correct. This appears to be a bug.
#1164

[bobqianic]

memcpy(&m_audio[0], &stream[n0 * sizeof(float)], (n_samples - n0) * sizeof(float));

The logic in this case isn't entirely flawless. Consider a scenario where your n_samples unexpectedly grows to be much larger than m_audio.size() – for instance, ten times larger. This could result in undefined behavior, as it involves attempting to write data beyond the bounds of the array.

whisper.cpp/examples/common-sdl.cpp

Lines 152 to 165 in e2f0eba

	if (m_audio_pos + n_samples > m_audio.size()) {
	const size_t n0 = m_audio.size() - m_audio_pos;
	memcpy(&m_audio[m_audio_pos], stream, n0 * sizeof(float));
	memcpy(&m_audio[0], &stream[n0], (n_samples - n0) * sizeof(float));
	m_audio_pos = (m_audio_pos + n_samples) % m_audio.size();
	m_audio_len = m_audio.size();
	} else {
	memcpy(&m_audio[m_audio_pos], stream, n_samples * sizeof(float));
	m_audio_pos = (m_audio_pos + n_samples) % m_audio.size();
	m_audio_len = std::min(m_audio_len + n_samples, m_audio.size());
	}

[ggerganov]

Thank you for spotting this!

Could you check #1523 - I think it should fix the issues