*** GMX Spamverdacht *** [MPlayer-dev-eng] Re: [PATCH] support for On2 vp6.2 video codec

Reimar Döffinger Reimar.Doeffinger at stud.uni-karlsruhe.de
Mon Mar 15 17:19:02 CET 2004


>>You shouldn't compress such a small patch - like this at least I can't 
>>simply read it in the mail client but instead have to save, uncompress, 
>>open - too much work.
> I apologize but it was the only way I could send an email without the lines
> wrapping.
Ok, just thought maybe you didn't know what you were doing ;-)

>>In addition I would suggest a modified version that does some checks. It 
>>would be also nice if we could get On2's agreement for this...
> I did not know we needed their agreement since we did not supply any codecs,
> make any enhancements or build anything to sell.
> The end user is the one who is downloading codecs from their site. 
> Does it matter if you use personal edition codecs on linux versus windows to
> play their media files. 
Maybe we don't need it, but that code actually modifies data for which 
they have the copyright. So it might be illegal to use that code part...

>>Any comments on this?
> I like the checks which you added making it much better. 
> I cant test the vp5 or older vp6 codecs myself but it looks good.
> Info the vp5 files on the ON2 website seemed to be non standard in their header
> slightly, MPlayer did not realize they were an AVI and did not read them.
> Only issue I see in the patch might be if someone has the 6.1 version of codec
> installed and tries to play a 6.2 encoded file since both versions have the 
> same filename vp6vfw.dll and VP62 fourcc is enabled in codecs.conf.
> I am thinking it will just not play.
No, it will crash with a segmentation fault (sig11). I added a comment, 
maybe this is enough.

> Other things I am working on currently.
> I havent been able to get the sound to work on any of the On2 vp5-6 
> encoded files except the .vpz samples from iraq using mpeg audio.
> the audio format is reported as 0x501. Believe this to be using the AVM
>  codec they have mentioned on their site.
They call it AVC, I think. A decoder for this format is contained in the 
RealPlayer VP4 codec pack, but the format of this codec isn't supported 
by MPlayer (It seems Real switched to an object-oriented format for 
their plugins some time).

> I also havent been able to get the Windows Media 9 speech codec wmspdmod to 
> work. format reported as 0xA.
> (Some online radio stations etc use this format apparently)
> audiocodec wmaspdmo
>   info "Windows Media 9 Speech DMO"
>   status untested
>   format 0xA
>   driver dmo
>   dll "wmspdmod.dll"
>   guid 0x874131cB, 0x4ecc, 0x443b, 0x89, 0x48, 0x74, 0x6B, 0x89, 0x59,
>  0x5d, 0x20
> Repeated error and no audio.
> Win32 Warning: Unlocking unlocked Critical Section 0x83c09b8!!
> Problems like this have been mentioned on mailing list before I believe.
Simply commenting out this message doesn't help?

> My latest codec attempt is on a Video codec which has two Dlls A and B.
> I load A.dll in codecs.conf using the dshow driver.
> I was able to implement the missing advapi32.dll function RegCreateKeyA 
> inside win32.c from the wine source code for this dll.
> (used to Store a key something about the company in registry)
I would have thought a simple stub implementation might have worked as 
well, but that's not so important...

> but the decompress frame function is in the B dll and is also unknown.
> (B dll just has two functions compress and decompress frame)
> obviously at this point since it cant decompress frames the playing fails.
> Unsure how to proceed. I cant implement the function myself as the codec
> algorithm is unknown to me.
> And I am unsure how to allow the exported function in B.dll to be called
> from A.dll.
> Any tips would be welcomed.
How does this A.dll try to use B.dll? If it uses static imports it 
should work automatically (have a look at loader/pe_image.c, line 293 
and following).

Reimar Döffinger

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