In the Pacino film The Merchant of Venice, when Shylock begins "I am a Jew", to whom are his words addressed, and is he provoked into these words?
In 3.1.46, is Shylock in a calm or a distracted mood when he encounters Salerio and Salanio, and should he appear bruised and bloodied?
Shylock is an extremely complex character rather than the sterotype as he is often portrayed. First and foremost, he is a human being. As a Jew in Venice at this time he is a second class citizen and he has felt the prejudices aimed at him all his life. He loves his daughter and she has betrayed him by running off with a Christian (the enemy) and taking valuables including a ring given to him by his dead wife, Leah.
When he is taunted by Salerio and Salanio, it is the straw that breaks the camel's back so to speak. The speech is not a plea for sympathy. The speech is beautifully built as Shylock compares Jews and Christians. The speech is a logical justification of his intenstion to get revenge.
As for him being bruised and bloodied, I find that unnecessary. It seems gratuitous.
Since we're limited to answering one question at a time, I'll address your question about Shylock's "I Am a Jew" speech. While in the play and in Al Pacino's film version, Shylock is talking to Salerio and Salanio, his speech is really a lesson from Shakespeare to his Elizabethan audience and, more specifically, is an expression of Shylock's desperate desire to be taken seriously by Venetian society.
When Salerio and Salanio approach Shylock, he is already agitated and most likely has a poor history with Antonio's friends. So, while they do not necessarily cause him to voice his frustration about how he is treated, running into them is rather like the last straw for Shylock. He is at his breaking point. His daughter has absconded with a Christian and with his jewels, and he is anxiously excited about the possibility of revenge upon his rival Antonio. Thus, when Salerio and Salanio approach him, all of those emotions poor forth in his speech. Of course, Shylock's eloquent outburst does not win him sympathy or fans. Those who hear his speech mock him and feel that his behavior gives credence to their pre-existing disdain for him.
In regards to the versions portraying him bloodied and beaten, I personally don't care for them because they provide immediate motivation for Shylock's speech. However, Shakespeare develops early on in the play a history of constant verbal abuse directed toward Shylock. I think that a more accurate portrayal of Shylock's volatile state is Al Pacino's version.