Method GetSamplesPerFrame

src/Frame.cpp:456–481

Calculate the # of samples per video frame (for a specific frame number and frame rate)

// Calculate the # of samples per video frame (for a specific frame number and frame rate)
int Frame::GetSamplesPerFrame(int64_t number, Fraction fps, int sample_rate, int channels)
{
	// Directly return 0 for invalid audio/frame-rate parameters
	// so that we do not need to deal with NaNs later
	if (channels <= 0 || sample_rate <= 0 || fps.num <= 0 || fps.den <= 0) return 0;

	// Get the total # of samples for the previous frame, and the current frame (rounded)
	double fps_rate = fps.Reciprocal().ToDouble();

	// Determine previous samples total, and make sure it's evenly divisible by the # of channels
	double previous_samples = (sample_rate * fps_rate) * (number - 1);
	double previous_samples_remainder = fmod(previous_samples, (double)channels); // subtract the remainder to the total (to make it evenly divisible)
	previous_samples -= previous_samples_remainder;

	// Determine the current samples total, and make sure it's evenly divisible by the # of channels
	double total_samples = (sample_rate * fps_rate) * number;
	double total_samples_remainder = fmod(total_samples, (double)channels); // subtract the remainder to the total (to make it evenly divisible)
	total_samples -= total_samples_remainder;

	// Subtract the previous frame's total samples with this frame's total samples.  Not all sample rates can
	// be evenly divided into frames, so each frame can have have different # of samples.
	int samples_per_frame = round(total_samples - previous_samples);
	if (samples_per_frame < 0)
		samples_per_frame = 0;
	return samples_per_frame;
}

// Calculate the # of samples per video frame (for the current frame number)
int Frame::GetSamplesPerFrame(Fraction fps, int sample_rate, int channels)