[NUT-devel] a few things about nut.txt

[Michael Niedermayer]

Hi

On Fri, Nov 24, 2006 at 11:14:58AM -0500, Rich Felker wrote:
> On Fri, Nov 24, 2006 at 01:34:44PM +0100, Michael Niedermayer wrote:
> > > 3.) There is no explanation of what EOR actually means.
> > 
> > end of relevance pretty much marks the start of a gap in a stream (no video
> > or no audio or no subtitles until the next keyframe) it is (with the
> > exception of a EOR after the very last frame) AFAIK relatively nut specific
> > (= will probably never be used by anyone)
> 
> It's absolutely needed for subitles or seeking performance will be
> utterly abysmal. Consider a movie with 5 subtitles at 5minutes and 5
> subtiles at 70 minutes and none in between (yes I actually have a
> movie like this). We wouldn't have added it if it weren't actually
> needed.
> 


[...]
> 
> > * nut files with EOR cannot be converted to other containers or more
> >   correctly you cannot seek correctly in the resulting file
> 
> Not true.

wait, EOR is "absolutely needed" and it works in containers which dont have
EOR, how can both be true?

just try:

Sub: K                                   K
Vid: KFFFFKFF..1hour..KFFFFKFF..1hour..KFFF

you can either
A. ignore the subs and seek purely based on the video stream (will not
   display subs after seeking)
B. seek to previous keyframe of all streams (will not allow you to seek
   into the 2 hour segment without sub keyframes


> 
> > * lav* does not support it (and i dont plan to change that), for lav*
> >   gaps are not allowed, you will have to encode black/silence/no subs
> >   keyframes (which require only negligible storeage anyway)
> 
> The nut muxer should automatically generate EOR for subtitles and not
> use it anywhere else (except perhaps eof). Just repeating an 'empty'
> subtitle every few seconds is an ugly hack.

IMHO EOR is a ugly hack, puting keyframes where you want to seek to is
the correct thing to do

also if you have a special case for "whole screen transparent" then why
not for black frames or no audio? or gray frames or white frames ...
this does make at least as much sense as for subtitles, think of a audio
stream with music, one with actors voices, one with commentary, one with
special effects, ...
having this split would be VERY nice, and these streams would have alot
of large gaps which would benefit from EOR


[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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