Concentration camps
A concentration camp is generally a prison camp. However, the Nazis also made transit camps, work camps and extermination camps. All of these were also concentration camps.
In Germany itself there were never any extermination camps. The concentration camps at Dachau, Bergen-Belsen and Buchenwald were, of course, not pleasant places to be, but they were not equipped for industrial murder.
The extermination camps were all in Poland and some of the Baltic states. Poland had the most - Auchwitz-Birkenau, Treblinka and Sobibor, to mention the most notorious.
The camps shown in this film was shot, I believe, only by troops from the western Allies (UK, US, Canada). These show only concentration camps in Germany. The extermination camps in Poland and eastern Europe were liberated by Russian troops. They also took films, but I do not know if these films have ever been publicly released.
Unlike the German camps, I believe most of the extermination camps were emptied before the Russian troops arrived. I know the prisoners of Auschwitz-Birkenau were forced to march to another camp closer or in Germany before the troops arrived. Sobibor was closed and torn down after inmates killed half the Nazi guards and attempted a mass escape in 1943.