[MPlayer-dev-eng] Patches for NUT

[Rich Felker]

On Fri, Feb 03, 2006 at 01:05:36PM +0100, Michael Niedermayer wrote:
> > > 
> > > accurate compare_ts, 02-compare_ts.patch
> 
> there is something i dont like ...
> we should not force a specific implementation here which this more or less
> does, instead we should specify things more like:
> compare_ts
>     Compares timestamps from 2 different timebases, 
>     if a is before b then compare_ts(a, b) = -1
>     if a is after  b then compare_ts(a, b) =  1
>     else                  compare_ts(a, b) =  0
> care must be taken that this is done exactly with no rounding errors, simply
> casting to float or double and doing the obvious a*timebase >/<= b*timebase
> is not compliant or correct, neither is the same with integers, and
> a*a.ts.num*b.ts.den >/<= b*b.ts.num*a.ts.den will overflow
> one possible implementation which shouldnt overflow within the range of
> legal timestamps and timebases is:
> comare_ts(a, b){
>     if (convert_ts(a, a_timebase, b_timebase) < b) return -1;
>     if (convert_ts(b, b_timebase, a_timebase) < a) return  1;
>     return 0;
> }

I agree totally, this is basically what I said on irc.

> > > remove 2^n header restriction, 03-header-repeat.patch .
> 
> ok

IMO the wording is slightly confusing and makes it sound like the
headers must be repeated at EACH 2^n position.

> > > Regarding error recovery michael suggested, checksum for frame header etc.
> > > I dislike it, it complicates binary search when looking for startcodes.
> > > Rich already proposed a solution to prevent loosing the entire file - if
> > > you see a frame with abnormally high size immediately after a syncpoint,
> > > while reading the frame (which you have to anyway), linear search entire
> > > area for possible syncpoint. The worst that will happen is that you'll skip
> > > the entire damaged area in that single frame, and that's actually a good
> > > thing...
> 
> ok, but that still leaves the issue with abnormally high pts and damaged pts
> during binary search

Hmm..
I'm ok with having checksums but I'd like to hear other ideas too.

Rich