<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">Hello all,<div><br></div><div>I am currently examining avf_showspectrum.c and I have a few questions that I am hoping you guys can clarify for me:</div><div><br></div><div>(This is the command I am running, BTW: ./ffmpeg -i input.mp3 -filter_complex showspectrum=mode=separate:color=intensity:slide=0:scale=cbrt -y output.avi)</div><div><br></div><div>1) First it is about the output: I am assuming the plotted image has time horizontally, the frequency range vertically, and the intensity of color as the amplitude. Is that correct?</div><div><br></div><div>2) In plot_spectrum_column() function, the code copies some amount of the data to the rdft_data:</div><div><blockquote type="cite"> s->rdft_data[ch][start + n] = p[n] * s->window_func_lut[start + n];</blockquote><br></div><div>and then performs a av_rdft_calc() on the data. But it's never clear the s->rdft_data array, does this mean the plot is cumulative over time?</div><div><br></div><div><br></div><div>Thanks in advance.</div></body></html>