Please explain codecs to me: codecs within codecs?

[idsane]

Can someone tell me how this works and please correct anything I have wrong:

Dvds use MPEG2 codec, bluray MPEGpt10, which is AVC/h.264... am I right so far???

Ok... now for audio .... is there another codec within the above ones? So Ac3 codec for DVD and AAC codec for bluray???

Finally... is there yet a third codec within the last one? So AC3 can contain dolby digital and DTS, and AAC can contain those plus all the new dolby and DTS formats?

Thanks for you help!

[jagabo]

Video and audio use different codecs. DVD/Blu-ray can contain multiple audio streams, each compressed with a different codec.

[lordsmurf]

Single video stream
Multiple audio streams
Subtitles streams, NAV data, and other stream data
All wrapped inside a wrapper of some kind.

Example: DVD
- MPEG-2 video
- AC3 + PCM + DTS audio
- English + Spanish subtitles
- Wrapped in VOB files
- Disc can also hold data, such as the video thumbnails/wallpaper (hit STOP on DVD player), games and other DVD-ROM computer content, etc, outside the VIDEO_TS/AUDIO_TS DVD-Video format structure (ROM folder or anything else), even autoplay commands, software installers, etc.

It's complicated -- but it's not.
Of course, MAKING IT and UNDERSTANDING IT are different animals. Actually making such a complicated disc can have a learning curve. Even I'm still learning some of the things can can be made possible for a complex DVD structure.

[idsane]

Hey thanks for the explanation. So my VOB files on my DVDs have an MPEG2 video and an AC3/dolby digital signal wrapped into one file. The main reason I am asking is b/c I want to know how bluray format works. Right now I am re-encoding a lot of my dvds to h.264 courtesy of nero recode. So this is making one MP4 file containing a video and multiple audio streams in AAC. If, in the future, I want to package these together for a disc that will play on a bluray player, is this format going to allow me to do so without having to re-encode yet again. Are files on bluray discs mp4 files? I am concerned about the sound file in them also, since most new receivers decode all the dolby formats, but I don't see anything about AAC?

[minidv2dvd]

in the upper left of the screen click on "what is"/"blue-ray" . there you will find the specs. mp4 with aac audio is probably not going to play on a blue-ray disc as it's not a supported audio format.

[edDV]

There is standard Blu-Ray player support (upper left) and individual player issues that might allow a wider choice of codecs and encoding limits (e.g. PS3).