[linux-dvb] Re: Cutting

[Christoph Ackermann <ackermann@cms.tecmath.com>]

Hi Matthias,

MPEG2 is defined by a "Group of Pictures" similar to IBPBBPBBPBBP. A GOP
starts wihth an I-Frame wich is displayable "standalone". The next
pictures are B- and P-Frames. These pictures  contain only the
differences between the original frame and the I-Frame and are not
displayeble "standalone". You have to reencode the whole GOP and extract
the desired frame(s).
If you want to connect two clips with reencoded starts/ends you have a
problem, because the GOP-sequence is not circular and you get a "jitter
effect" at the editpoint.
One way to a "clean" solution is to reencode the whole clip an cutting
in a transparent (uncompressed) mode. Be aware -> Each frame needs 1,2
MByte (RGB). For one hour of Video you need 108 GB space on your
harddisk.
Second way is to reencode in "I-Frame only" mode with 50 Mbit/s and cut
your movie at any point  you like. This mode needs only 30 GByte/hour
and is used by most profesional NLE´s (Non-Linear-Editing) 
 

Matthias Queisler wrote:
> 
> Is it possible too make the editing more exactly? Half a second is to much.
> I know the prob with the I-Frames etc. but isn't it possible?
> About the commands.conf. Is it only possible to make an outpu with it or can
> you make input like a number or another sub menu?
> cu


Regards,
Christoph 
________________________________________________________________________

Christoph Ackermann                                    ] t e c m a t h [
System Integration Engineer          Content Management Systems Division
phone +49 6301 606-200      Sauerwiesen 2, 67661 Kaiserslautern, Germany
fax   +49 6301 606-209                            http://www.tecmath.com
________________________________________________________________________


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