[MPlayer-dev-eng] [PATCH] wmv9dmo - correct supported output formats

[John Koleszar]

Ivan Kalvachev wrote:

>I'm very against this patch!
>
>WMV3 decoder just like most of the modern decoders use internal planar format.
>This means that the other format require convertion by software.
>Even if we ignore the cpu computation needed for yv12->yuyv convertion
>(that is not much if done in mmx),  the yuyv packed formats are 16
>bits per pixel and this increase the required  memory thoughput.
>
>  
>
I'm well aware of all of this. Just because they're using a planar 
format internally, doesn't mean it's yv12 though. I have to imagine that 
it would be supported as a first class output type if it were.  The 
DMO_VideoDecoder code currently rounds 12bpp up to 16bpp for calculating 
the frame size while setting the output format, and without this step, 
it never is able to decode a frame. This makes me even more skeptical 
that the image is actually yv12.

 From what I've seen, it sort of looks like they could be using 
different chroma sampling in their internal buffers. In particular, it 
looks like the chroma's not subsampled in the vertical direction (like 
yv16?), resulting in a vertical chroma stretch. I'm at a loss to 
describe the horizontal direction though.. Could just be a bug in the 
routine that copies the data from the internal buffers to the external 
one. In any case, it seems to me that the problem is within the dll and 
not mplayer, which is why I patched it as I did. Wasn't trying to 
band-aid it.

If someone wants to look into it, a good starting point is the change 
made in this rev:
----------------------------
revision 1.7
date: 2003/09/20 00:52:51;  author: pl;  state: Exp;  lines: +3 -2
fix for the no video/black screen with some dmo/wmv9 movies
(for some videos: bits=12 and once /8 the allocated buffer is 50% too small)
----------------------------

Does anyone have a clip where this works right? I'd be curious to look 
into that.

>Provide sample and let us find out why it doesn't work.
>
>  
>
Enjoy:

ftp://opensource:opensource@ftp.on2.com/saturn_720x480_1000kbps_bestq_wmv3_5sec.avi

John