Video templating

[rumkin]

Hi. I'm searching for solution of video templating issue for web streaming.
I've got video which could be changed on the fly on demand and then streamed. I want to make it fast.
My goal is to split video file into small chunks (and store chunks in separate files) which will be a build blocks of final video, then change some of chunks (frame data only, no duration changes) on demand and concat chunks to get the result video.
My goal is to limit computations and simplify concatenation if it possible to simple cat.
So is it possible to do it this way with mp4Box?

[jeanlf]

1. what do you mean by "change some chunks (frame data only)" ? If you change frame data, you need re-encoding of the whole chunk. This may have impact on codec compatibility of the new encdoded data and the existing file , you need to mke sure the same codecs settings are used...

2. using simple cat may only be possible if the modified chunk has exactly the same duration as the source one. One way to do so is 👍

• to prepare the video as a set of fragmented files (say 1 sec), using for example "-dash" option of MP4Box in "live" profile
• whenever you have to edit one fragmented file, concat the init segment and the file (simple cat) and edit (if needed, unfrag the file using -inter 500). To refragment the result, use -dash option on the modified video, with the -tfdt N where N was the tfdt time of the edited segment (you can use -diso frag.m4s to find the tfdt).
• when you have to distribute the result, concat (simple cat) the init segments and all the fragmented files.

hope this helps

[rumkin]

Great thanks for your answer.

1. "Change some chunks (frame data only)" means that I want to change pixels. No audio channel or duration changes. Drawing only.
2. I will try this. Thank a lot.

[cconcolato]

@rumkin Can we close this issue?

[rumkin]

Nope, yet.