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Encapsulation Method and Transcoding...

Posted: 04 Jan 2006 18:18
by TaskyZZ
Can someone enlighten me a little more on this?

Encapsulation is the method the data is transmited, is that correct? Even if it is just being streamed to a file, it is still transmitted in this format before actually getting written.

Then it gets written to disk. And the Transcoding Options decide how that is done. So, if I choose mp4v then it is written to disk in the mp4v format.

Does the Encapsulation Method affect the quality of the final file? Is Mpeg TS or PS better or worse than MOV or MP4, or does it not affect final quality? How do we choose what bitrate and whatnot the Encapsulation Method is using, or does that not matter?

And just to give a little more info, I am doing a capture from a video capture card, not streaming a file from somewhere like network or file. I am capturing video from a video capture card and writing it to disk.

Thanks for any help, I am just trying to understand this all a little better.

Posted: 05 Jan 2006 13:08
by dionoea
encapsulation only affects the way in which the data is ordered in your stream/file. Quality is depends 'only' on the codecs you choose, not the encapsulation.

For example, if you have 1 video elementary stream (es) VVVVVV and 1 audio es AAAAAAA, you could "mux" them this way:
VAVAVAVAVAVA
or this way:
VVVVVVAAAAAA

This is of course really simplified.

Posted: 11 Jan 2006 06:33
by cyberfunk
After reading this, I'm still confused, and had the same question I think:

Allow me to rephrase part of the question: Is the encapsulation setting regarding the format for the INPUT stream or the OUTPUT stream ? I seem to think it's the output stream, because doesnt VLC auto-detect the input one ?

Posted: 11 Jan 2006 13:41
by dionoea
the input encapsulation method is automatically detected by VLC. You can set the output encapsulation method (and no, it won't affect quality)

Posted: 11 Jan 2006 17:33
by TaskyZZ
I see, so it affects how the data is arranged to be transmitted, but it doesn't effect the content of the data... Is this correct? That makes sense.

Thanks.

hello

Posted: 11 Jan 2006 18:19
by h2g2bob
As I see it, the encapsulation works like a box, into which you put your audio and video - you make your audio and video formats what you want (like DivX, Mp4v, etc).

Then you put the video and audio in a box - this holds them together, and can also hold things liek a name and copyright message and stuff.

Certain encapsulation methods only suppost certain file formats - the "Muxer / audio and video formats matrix" bit of http://www.videolan.org/streaming/features.html has a list of what video and audio can be put in what box.

Muxer is (I think) another name for encapsulation

mpeg4 for Ipod

Posted: 15 Jan 2006 07:45
by maxdas
sorry to disturb the ongoing discussion but i'm new to VLC and this seemed like the right forum place to ask about mpeg 4 format for ipod.

what do i have to do to make an avi file become an mpeg4 ipod video file?

any help is appreciated.

Thanks in advance.