4.9GB Vid + 2.1GB Aud = 8.6GB?!?!?

[BurkettC]

Please forgive me if this has been answered before, but I had trouble phrasing the problem in a search (and boy did I try):

I am succcessfully creating an AVCHD structure from:

4.9GB .264 Video
2.1GB .ac3 TrueHD+AC3 Core Audio

Simple math would suggest that this would clock in AROUND 7GB....maybe 7.5GB..... But 8.6GB?!?!?

I think I narrowed it down to the audio stream as I created an m2ts with just the audio. It went from 2.1GB to 3.4GB. What the heck is that?

GB, in this case is just the simple, inaccurate removal of the extra numbers (2,143MB=2.1GB)

Thanks!

- Colby

[bmo]

The AVCHD/Blu-Ray structure has a bit of overhead built in so the increased file sizes you're seeing is normal.

[BurkettC]

Thanks for the reply bmo. I hear you on the overheard part, but 70% on one file? That actual m2ts is increasing by 70%. My other muxing successes have not gone anywhere near that figure. I just did a 530MB 640Kbps AC3 DD track and the m2ts came out to 620MB.... about 20%.

I am going to extract a different TrueHD track and mux it (by itself) to see what happens. This is just bizarre.

Thanks!

- Colby

[BurkettC]

This is disgusting. I just did another TrueHD+AC3 Core track and a similar thing happened. The file is 3.8GB by itself, but muxed to an m2ts (alone), it is 4.9GB.

That doesn't sound like overhead, that sounds like blatant robbery. Granted, the difference, this time, is around 25%, but what the heck is happening that is requiring 1.1GB of wrapper for THD audio streams? Is it some kind of spaced-out structure for buffering reasons or easier processing on the playback equipment? I am just trying to figure out why >1GB is lost in neverland..... and it's not predictable, so I can't tell what kind of bitrate to employ on the h.264 stream.... unless I pre-mux the audio stream to find out the end result.

There has to be a technical explanation for this.... anyone?

Thanks!

- Colby

[jman98]

I don't know the answer. If nobody else here does, maybe you should ask on the forums at http://www.doom9.net. Doom9 has some heavy duty people who probably do know the answer, the only question will be whether any of them care enough to respond or not (Doom9's forums are not always friendly).

[Baldrick]

I guess you are using tsmuxer?

[BurkettC]

Yep, tsMuxeR 1.10.6.

I'll check doom9 as well......

Thanks!

- Colby