pub fn start_convert(opts: ConvertOptions) -> Arc<Progress>Expand description
Start a conversion; progress 0..1 by parsing ffmpeg -progress pipe:1 (out_time_us) against the
input duration from ffprobe. codec_args(ext, ...) from export.rs picks the codecs; gif gets
fps=<gif_fps>[,scale=...:flags=<scaler>],split[s0][s1];[s0]palettegen[p];[s1][p]paletteuse.