How does DOM operate when modifying an existing Project?
Posted: Thu Apr 12, 2018 6:20 am
First question: is there a proper name for what I'm calling a Project (I borrowed the name from Premiere)?
Now for some questions about how DCP-o-matic operates when modifying an existing Project.
Test 1
I have a test Project that contains six files:
• five ProRes 422 HQ files
• and a previously encoded DCP file from DoM, containing 90% of the total video material.
When I made a new DCP, the encode ran through very quickly because most of the encoding had already been done on the 90% material.
Test 2
Then I made another change: I added a 5-second video clip in the middle. I assumed that the encode would really fly this time because 99.5% of the encode had already been done. I also assumed that, during encoding, each individual clip would be stored as a separate encoded file, and then assembled together at the end. But no, the encode was slow.
So I went looking for all these video files in my Project folder, and found three large ones. Two were identical in size, but different in name. One of those files is in the "video" folder, the other in the folder destined for ingestion by the cinema. And there is another large file in the "video" folder, roughly the same size. I assume this one was the previously encoded DCP.
Ques 1
When making the DCP, I asked for the previous file to be overwritten. Yet I still have 5.6GB of the previous DCP in the "video" folder. Does it serve some purpose to keep the old version?
Ques 2
Why are there two copies of the new video file? What purpose is served by keeping the extra copy in the "video" folder? Any problems in deleting it?
Ques 3
If I make a minor change to a Project, such as a 5-second addition in the middle, does DoM make use of any previously-encoded video files in the "video" folder? Meaning: does DoM say to itself: "Hey, I encoded most of those clips last week, and they ended up inside a video file I made called 'XXX'. This bloke hasn't made any changes to the clips, so clever me -- I'll just extract the relevant frames and reuse them."
Ques 4
If I make a minor change to an already-encoded Project, is it possible to reduce encode time, given that most of the encoding has already been done?
Now for some questions about how DCP-o-matic operates when modifying an existing Project.
Test 1
I have a test Project that contains six files:
• five ProRes 422 HQ files
• and a previously encoded DCP file from DoM, containing 90% of the total video material.
When I made a new DCP, the encode ran through very quickly because most of the encoding had already been done on the 90% material.
Test 2
Then I made another change: I added a 5-second video clip in the middle. I assumed that the encode would really fly this time because 99.5% of the encode had already been done. I also assumed that, during encoding, each individual clip would be stored as a separate encoded file, and then assembled together at the end. But no, the encode was slow.
So I went looking for all these video files in my Project folder, and found three large ones. Two were identical in size, but different in name. One of those files is in the "video" folder, the other in the folder destined for ingestion by the cinema. And there is another large file in the "video" folder, roughly the same size. I assume this one was the previously encoded DCP.
Ques 1
When making the DCP, I asked for the previous file to be overwritten. Yet I still have 5.6GB of the previous DCP in the "video" folder. Does it serve some purpose to keep the old version?
Ques 2
Why are there two copies of the new video file? What purpose is served by keeping the extra copy in the "video" folder? Any problems in deleting it?
Ques 3
If I make a minor change to a Project, such as a 5-second addition in the middle, does DoM make use of any previously-encoded video files in the "video" folder? Meaning: does DoM say to itself: "Hey, I encoded most of those clips last week, and they ended up inside a video file I made called 'XXX'. This bloke hasn't made any changes to the clips, so clever me -- I'll just extract the relevant frames and reuse them."
Ques 4
If I make a minor change to an already-encoded Project, is it possible to reduce encode time, given that most of the encoding has already been done?