[NUT-devel] Info packets in NUT stream (spec bugs?)

[Oded Shimon]

On Sun, Nov 05, 2006 at 09:32:44PM +0200, Oded Shimon wrote:
> On Sun, Nov 05, 2006 at 07:07:22PM +0100, Michael Niedermayer wrote:
> > On Sun, Nov 05, 2006 at 09:48:46AM +0200, Oded Shimon wrote:
> > > On Sun, Nov 05, 2006 at 12:19:53AM +0100, Michael Niedermayer wrote:
> > > > the big problem with simply allowing arbitrarily placed info is that it 
> > > > makes the info useless for the normal nut file case as the info cannot be
> > > > found its like a dvd with chapters but the information about where the
> > > > chapters begin is stored at the begin of the chapters, you end up with
> > > > a O(n) search ...
> > > > so ive some concerns with just saying its ok for streaming, as that
> > > > leads to nut files laying around which are encoded for streaming ...
> > > 
> > > The proposal I had for this is - info packets not written after main 
> > > headers are only allowed in real time streaming, and must have 
> > > chapter_id!=0, and any info packets written after main headers, both in 
> > > file and in streaming scenario, MUST be repeated together with all main 
> > > headers. No demuxer would have to search anything past main headers, any 
> > > info packets given during demuxing is "information update". In the file 
> > > scenario, all info must be written after the main headers, so no searching 
> > > necessary.
> > 
> > hmm, rich what is your oppinion about that? iam unsure if iam against it
> > or not ...
> 
> - ods15

Objections? Commit? 48 hour notice from now.

- ods15

> Index: DOCS/tech/nut.txt
> ===================================================================
> --- DOCS/tech/nut.txt	(revision 20666)
> +++ DOCS/tech/nut.txt	(working copy)
> @@ -180,11 +180,15 @@
>              packet_header, index_packet, packet_footer
>          }
>          if (!eof) while(next_code != main_startcode){
> -            if(next_code == syncpoint_startcode){
> -                packet_header, syncpoint, packet_footer
> +            packet_header, syncpoint, packet_footer
> +            do{
> +                frame
> +            }while(next_code == framecode);
> +            reserved_headers
> +            if (realtime_stream) while(next_code == info_startcode){
> +                packet_header, info_packet, packet_footer
> +                reserved_headers
>              }
> -            frame
> -            reserved_headers
>          }
>      }
>  
> @@ -836,9 +840,15 @@
>  Info:
>  -----
>  
> -If a info packet is stored anywhere then a muxer MUST also store an identical
> +All info packets stored after a main header set MUST also have an identical
>  info packet after every main-stream-header set
>  
> +All info packets not stored after a main header set MUST have
> +chapter_id!=0 .
> +
> +Info packets MUST be written after main header sets in non realtime
> +streams.
> +
>  If a demuxer has seen several info packets with the same chapter_id and
>  stream_id then it MUST ignore all but the one with the highest position in
>  the file