[MPlayer-dev-eng] [PATCH] Alternative RealAudio decoder

Florian Schneider flo-mplayer-dev at gmx.net
Thu Jun 13 16:26:56 CEST 2002


Arpi wrote:
> Hi,
> 
> i really didn't want to duplicate your work :(
> i've just found it easy to implement based on your docs, of course it turned
> out at the end that it is not so easy (interleaving etc) but i didn't gave
> it up then ;)
> 

I have only understood parts of the interface at that time. This 
interleaving had been an interesting thing - it took some time to 
understand what they really want.

> 
> yes, i see it in your patch now
> anyway it's more difficult imho, there is the lotr_trailer2.rm, it plays
> well with 20fps, but actually it uses 30fps, but lots of skipped frames
> 

How (and why) did they do that? When I understand you correctly, the 
player gets the information that the frame rate is 20 fps, but then 
playing we get 30 frames per second and we have to remove several frames 
by ourselves.

There are some other problematic files (Pen3.rm on the ftp server) - it 
plays mostly garbage with sunday's cvs. Maybe it is fixed by now.


> anyway the trick i use is not perfect, when there are more B frames than the
> encoder predicted (when encoded the next reference frame), the timestamp is
> bad (behind the previous in time). in such cases i have to re-calc it, by
> adding 1/fps to the previous valid timestamp
> 
> i've found what the numbers in transform_out[5] means:
> [0] - number of decoded frames (zero for first P frame after I)

counted from the last I-frame? sorry, but I've never tried to understand 
the values (except the last two)

> [1] - flags: keyframe, predicted frame (frame type I/P/B can be determined)
> [2] - timestamp (it's calculated from that 12 bits in video data and the
> packet timestamp you pass in transin1[])
> [3] - w
> [4] - h
> 
> so, realplayer probably gets the accurate timestamp (so fps is not used)

When I understand you correctly, the problem still persists. Can't check 
it here (windoze machine).

>>from the video decoder.
> 
> anyway rv30 is nice, it uses 2..6 B frames between P frames
> 

Is the problem only in rv20?

BTW: Does anyone know a Region 2 DVD (sold in Germany) that uses 
multiple angle extensivly (not only "präsentiert" <-> "presents") and is 
no adult movie? I'd like to have different views or un-cut scenes, i.e. 
different versions of the movies.

Regards

Flo




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