I’m not aware of any footage of the actual meeting where the bomb was planted. There very well could be footage of other meetings where Stauffenberg was present.
The only time I saw it was in school. I've never seen it again. I believe it to have been some sort of reproduction movie. It was black and white. Silent if I remember correctly and the distiguishing feature was the captioning on the footage in and around the Wolf's Lair giving it the look of security camera footage.