[FFmpeg-devel] MOD support for FFmpeg (My GSoC 2010 task starts tomorrow)

Michael Niedermayer michaelni
Fri Jun 11 02:02:37 CEST 2010


On Fri, May 28, 2010 at 03:43:49PM +0200, Sebastian Vater wrote:
> Michael Niedermayer a ?crit :
> > On Fri, May 28, 2010 at 02:13:37PM +0200, Sebastian Vater wrote:
> >   
> >> Peter Ross a ?crit :
> >>     
> >>> On Fri, May 28, 2010 at 12:54:46PM +0200, Sebastian Vater wrote:
> >>>   
> >>>       
> >>>> Michael Niedermayer a ?crit :
> >>>>     
> >>>>         
> >>>>> Its also a long standing feature request to make encode/decode_audio() work
> >>>>> with AVFrame or a similar structure instead of int16_t*
> >>>>>   
> >>>>>       
> >>>>>           
> >>>> For MOD, AVFrame could then point to an AVModule/AVSequencer/AVComposer
> >>>> structure which contains everything else needed.
> >>>>     
> >>>>         
> >>> In regular audio/video files, an AVFrame refers to a specific slice of
> >>> time (a frame of video, or as michael suggests, a chunk of audio).
> >>> In the context of Module files, what would an AVFrame refer to?
> >>>
> >>> If an AVFrame refers to a single pattern, how would this affect my ability
> >>> to seek through the tracker file.
> >>>   
> >>>       
> >> Normal audio players do time based seeking...I'm not sure right now if
> >> FFmpeg does support both types of seeking: time based as well as frame
> >> based seeking.
> >>
> >> If it supports frame based seeking, too. I would assign frame => order
> >> list number.
> >>     
> >
> > the API supports it (AVSEEK_FLAG_FRAME) i dont think anything uses it
> > though
> >   
> 
> Very fine. Then there's finally a reason to use them. ;-)
> 
> Since for tracker writers, exact frame (row based) seek is important, at
> least I use it pretty often while composing in IT (select row in pattern
> to start playback at and jam SHIFT-F6) ;-)
> 
> I also just reviewed my idea again by recognizing that it's a better
> idea to assign frame => order list number * pattern_size instead of just
> order_list.
> Let's say, we have a module with a order list length of 32 entries and
> each has a pattern with always the same size 64. Then the module would
> have 32*64 (=2048) frames instead of just 32. So seeking to order #5,
> row 32 would mean seeking to frame 5*64+32 = 352. What do you think
> about this?

I think you know these things better than i do and can decide these things
also better than i could :)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

I am the wisest man alive, for I know one thing, and that is that I know
nothing. -- Socrates
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