fprintf(stderr, "pktdumper file [maxpkts]\n");
fprintf(stderr, "pktdumper [-nw] file [maxpkts]\n"); fprintf(stderr, "-n\twrite No file at all, only demux.\n"); fprintf(stderr, "-w\tWait at end of processing instead of quitting.\n");
static int usage(int ret){    fprintf(stderr, "dump (up to maxpkts) AVPackets as they are demuxed by libavformat.\n");    fprintf(stderr, "each packet is dumped in its own file named like `basename file.ext`_$PKTNUM_$STREAMINDEX_$STAMP_$SIZE_$FLAGS.bin\n");    fprintf(stderr, "pktdumper file [maxpkts]\n");    return ret;}