[vdr] Re: vdr-1.0.0preX DVD addon v5 available

[Andreas Schultz <aschultz@cs.uni-magdeburg.de>]

Hi,

Sorry for the late answer,

Stefan Huelswitt wrote:
> On 24 Mar 2002 Andreas Schultz <aschultz@cs.uni-magdeburg.de> wrote:
> 
> 
>>A new version of the DVD add-on for the 1.0.0preX version of vdr is now
>>available at:
> 
> 
> I'm seeing a small (cosmetic, but annoing) problem in all your
> patches. As you are using a very big video buffer,
> forwarding/rewinding (specially slowmotion) is very inaccurate,
> this means there is a sudden jump of several seconds when the
> trickmode ist stopped.
> 
> I think this is because in trickmodes you only display I-frames
> and so the complete buffer is filled with i-frames. As every
> i-frame represents roughly half a second, this covers a big
> time. When stopping the trickmode, the buffer is cleared and you
> simply continues with your read pointer. This gives the jump.
> What have to be done is, to remember (or calculate) the read
> pointer for the front-most frame in the buffer and continue with
> that pointer. For more accuracy you will have to account the
> internal buffer on the card, too.
> 
> For normal replay I have done this in cBackTrace (dvbapi.c).
> Maybe you could make something like that for DVD replay, too.

You are right. For the DVD stuff to correctly identify the pickup point, a 
couple of additional information has to be attached to the frames. But i 
think the better and correct solution would be to change the buffer 
management altogether. I already have a version that uses libdvdnav, that 
will hopefully improve things. There are two thinks that currently stop me 
from releasing that version, 1. no ff/frew yet, 2. the API to libdvdnav 
will change real soon.

The libdvdnav based version will also solve some input/output thread timing 
related problems (like menus/subtitles too early...).

Andreas