[MPlayer-dev-eng] [PATCH] YUV4MPEG2 mencoder output format

[D Richard Felker III]

On Sun, Jan 09, 2005 at 04:12:31PM +0100, Roine Gustafsson wrote:
> 
> On Sunday, Jan 9, 2005, at 12:54 Europe/Stockholm, Reimar Döffinger 
> wrote:
> >>
> >>- Filters don't work correctly
> >
> >Please be more precise, this should not be the case.
> 
> This is not a bugreport; I just didn't get several stacked filters to 
> work with mplayer (filmdint+some other), and they worked fine with 
> mencoder. But then I had to use raw output, which was so painful I 
> wrote the muxer instead...
> 
> >>- Automatic colorspace conversions break losslessness of y4m
> >
> >mencoder should be doing them at exactly the same places. The (almost) 
> >only
> >difference between mencoder and mplayer is the code in mencoder.c and
> >mplayer.c...
> 
> No, the -vo yuv4mpeg does that internally.

Huh? If so that needs to be removed. VO drivers are not allowed to do
internal conversions...

> >>- Doesn't write colorspace information
> >>- Doesn't support pixel aspect ratios
> >>- Subject to frame droppings as it is part of a player
> >
> >MPlayer will _never_ drop frames unless you tell it to! mencoder is the
> >one you have to bug hard not to drop frames.
> 
> Really? This is news to me. Why would mencoder drop frames?? It doesn't 
> have anything to catch up to.

Because it outputs fixed-fps file, and input may not be (entirely)
fixed-fps. Also the A-V sync code does ridiculous things that cause
frame drops or duplication.

> >>- Only output to file, not to a pipe
> >
> >Huh? There is no difference between file and pipe on *nices
> 
> the yuv4mpeg vo creates and writes the files itself. The only option is 
> to use a fifo. With mencoder you (should) be able to do
> mencoder <yadda> -of y4m -o - | y4mscaler [...]
> which I prefer.

Nope. Not possible. mencoder writes lots of crap with printf so it
will get mixed into your output and ruin it... :)

> >>- Annoyingly will open a dummy window if scripted, since it's part of 
> >>a
> >>player
> >
> >Sorry??? I've never ever seen that, and I used it in scripts (see e.g.
> >mplmult.sh in the TOOLS dir)
> 
> Correction: it doesn't open a window, it creates a dock icon on the Mac 
> (like taskbar on Win). This is necessary when you want UI elements 
> (keypresses and windows). mencoder doesn't, so I prefer it.

This is probably a matter of how you compiled it. Maybe you enabled
the weird mac finder stuff recently added to MPlayer...?

> IMO this is different functionality for mencoder.
> I'm not very well versed in mplayer internals, but I'm willing to try 
> to maintain the code.
> I'd like to add interlacing support, but I don't know how mplayer 
> stores interlacing information internally. Any pointers?

Very simple: it doesn't.

BTW, I agree this functionality belongs in mencoder, not mplayer. But
lots of your reasoning (and things you want to do) are based on bad
assumptions IMO.

Rich