Mpeg2 mux overhead

[GZZ]

When you multiplex to streams, say an audio stream and a video stream in scenarist. Then you can calculate the Audio size and the video size, but when you multiplex them in scenarist the output size is a bit larger then the audio size + video size. I guess this is because scenarist add the packet header and other things to mpeg2 output stream. But are there anyway to calculate this 'overhead', so you can have a better way to tell the output size before you mux the streams in scenarist. ???


The reason I ask, is because I working on a calculator for DVD movies and I have found out if you don't calculate some sort of overhead, then your movie will be oversize. So if anyone can help me with a way to calculate this 'overhead' for mpeg2 streams, please help me.


GZZ

[jonjon51]

hello :)

I did few test some days ago, and I went to this conclusion:
(audio+video)*1.01995=audio+video(muxed)

I hope this can help
:)

[GZZ]

I did something like that, let me try out your result, it might be a bit better then mine. HEHE

[GZZ]

your number are lower the mine, I think its when you start using subs (they take more space) then just muxing video and audio. I think I have to calculate a mux overhead for both audio, video and subs (specially the subs). Because a sub might be 5 kb, but a sector are 2048 byte, so a sub will use 3 x 2048 byte = 6144 byte and thats a bit more then 5 kb. So if you do this for say 20000 sub files (10-20 languages), then it quite a bit, compared to audio and video which will not have this problem. Just an idea I have.

Maybe someone can verify it ?