<description>It can be used to force the decoder to return a certain number of frames. MPEGSource can not correctly create d2v files for MPEG-1 yet, so use this to input the correct number of frames. A value of -2 can also be written here. This means no d2v can be used and therefore only files can be inputed in the first parameter.</description>
<description>ff: forces film, nod2v: similar to the -2 command in that you can only specify files and nod2v is used or created. But it allows you to specify a number of frames in the "number of frames" parameter.</description>