\begin{description}
\item[Quality Option when rendering:] FFmpeg responds variably to the quality option in the render option but seems to respond well to bitrate. The subranges used by quality even seem to vary somewhat depending on how old the codec is. Some use $0$ to $35$, some use $0$ to $500$ or so. The quality is supposed to cause the codec to output data until the noise level is below a limit determined by the quality setting. Your specific results may vary.
\item[Previous Changes when rendering:] With ffmpeg there are 2 cases that the defaults will be used. The first time when you have nothing set up and any other time when you reset the render File Format in the Render Menu. Otherwise with ffmpeg, if you change a video compression type for the render (for example \texttt{h264.mp4} to \texttt{h265.mp4}), the settings will be from the previous session settings.
\begin{description}
\item[Quality Option when rendering:] FFmpeg responds variably to the quality option in the render option but seems to respond well to bitrate. The subranges used by quality even seem to vary somewhat depending on how old the codec is. Some use $0$ to $35$, some use $0$ to $500$ or so. The quality is supposed to cause the codec to output data until the noise level is below a limit determined by the quality setting. Your specific results may vary.
\item[Previous Changes when rendering:] With ffmpeg there are 2 cases that the defaults will be used. The first time when you have nothing set up and any other time when you reset the render File Format in the Render Menu. Otherwise with ffmpeg, if you change a video compression type for the render (for example \texttt{h264.mp4} to \texttt{h265.mp4}), the settings will be from the previous session settings.