Short answer: you don't need the cutscenes packs on that page to play the two Broken Sword games you mention.
Long answer: The original games contain cutscenes in
Smacker format. This is a proprietary format and initially we decided not to support it in ScummVM as the legality of doing so was questionable. So instead we reencoded the cutscenes, and with the benediction from the Broken Sword games creators made them available on our web site in DXA (for the video part) and either flac or ogg (for the audio part) formats. We provide the audio in both flac and ogg because while the former has better quality (it is a lossless encoding) it is not supported in ScummVM on all platforms. So ogg audio files are available as an alternative for those platforms on which we do not support playing flac audio files.
Nowadays however we support playing the original Smacker files. Thus the cutscene files on our website are no longer needed. If you still want to use them you just need to keep the dxa file and one set of either flac or ogg files (the ones for the language you want).
Note 1: Some re-release of the Broken Sword games use mpeg videos. This is because those re-release use ScummVM and initially we used mpeg and not flag to replace smacker cutscenes. Those re-release date back from that period. We still support reading those mpeg files, but the DXA ones from our web site may be slightly better quality (less encoding artefact - I think DXA is supposed to be lossless).
Note 2: Also we do provide a subtitle pack (I assume this is the one you mean when you mention .txt files). The original game didn't have subtitles for the videos, and this is an optional feature added by ScummVM. If you want to have subtitles just place the .txt files for the language you want in the same place where you have the video files (smk, dxa or mpg).
We should probably update that download page to avoid confusion from users...
