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OpenDivX digest, Vol 1 #23 - 5 msgs

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Today's Topics:

   1. libdecore for BeOS (Jonathan Tarbox)
   2. live streaming to java? (Dan)
   3. OpenDivX Decoder ->OpenDivX Forum Digest (Darrius "Junto" Thompson)
   4. OpenDivX Encoder -> OpenDivX (Darrius "Junto" Thompson)
   5. using mpeg2 decoding hardware for divx decoding (zap twentyfive)


Message: 1
From: Jonathan Tarbox <[email protected]>
Reply-To: Jonathan Tarbox <[email protected]>
Date: Wed, 21 Feb 2001 11:06:48 -0800
To: [email protected]
Subject: [OpenDivX] libdecore for BeOS

going by a cvs update as of a few minutes ago, the only thing needed to be 
changed for this to work within the BeOS is to add a variant of the function 
clearblock() in mp4_block.c and to use non-mmx code  (BeOS uses GCC and it's 
inline is AT&T syntax).

For the clearblock() code, you could use the Linux code, but here is an 
inline asm variant of it in AT&T syntax:

#ifdef __BEOS__
static inline void clearblock (short *psblock) {
	asm ("
		movl	$-16, %%edx
		movl	%0, %%esi

		pxor	%%mm0, %%mm0
		movq	%%mm0, (%%esi)
		add		$8, %%esi
		inc		%%edx
		jnz		0b
		: /* no outputs */
		: "g" (psblock)
		: "edx", "esi"

static __inline void clearblock(short * psblock)
	int i;

	for (i = 0; i < 64; i++) {
		psblock[i] = 0;

#endif // __BEOS__

I just converted the WIN32 inline asm over to AT&T syntax, this should prolly 
work for Linux as well.

Jonathan Tarbox

note: my involvement in this is personal, has nothing to do with Be, Inc.


Message: 2
Date: Wed, 21 Feb 2001 16:13:17 -0800
To: [email protected]
From: Dan <[email protected]>
Subject: [OpenDivX] live streaming to java?

is it possible to hook up a vcr/vcd/dvd to a capture card and stream
the aud/vid live to regular browsers using java or something?

anyone have any suggestions?



Message: 3
Date: Wed, 21 Feb 2001 18:35:41 -0800
From: "Darrius \"Junto\" Thompson" <[email protected]>
To: <[email protected]>
Subject: [OpenDivX] OpenDivX Decoder ->OpenDivX Forum Digest

Daily OpenDivX Decoder Forum Digest

Topic:		How to feed DECORE.... I am lost!
Author:		e7abe7a
Posted:		 2001-02-21 14:58
OK. The document is on CVS, in the ./divxcore directory. It's in TXT
I hope it helps!

Topic:		How to feed DECORE.... I am lost!
Author:		e7abe7a
Posted:		 2001-02-21 14:59
Two postings!=20
Same answer... see above message.

Topic:		How to feed DECORE.... I am lost!
Author:		mindpower
Posted:		 2001-02-21 16:37
Hm, I get a "no such file" message ...

Error: /Codec Core Interface.txtCodec Core Interface.txt: no such file
or directory =20
[ This message was edited by: mindpower on 2001-02-21 17:06 ]

Topic:		How to feed DECORE.... I am lost!
Author:		czw
Posted:		 2001-02-21 17:42
Direct link to the CVSWeb page:

Topic:		How to feed DECORE.... I am lost!
Author:		mindpower
Posted:		 2001-02-21 18:29
The document mentiones a flag DecParam.output_format which does not
exist in the version of decore.h that is available for download on the
project page.

Using this version (old?) version... what is the pixel format? is it
RGBRGBRGB and so on or something entirely different?

BTW: I managed to "play" the divx showcase AVI in PocketPC emulation and
I could see a distorted DivX Logo. Because the shape was there I assume
that just my interpretation of the output date of decore is wrong.=20



Message: 4
Date: Wed, 21 Feb 2001 18:36:29 -0800
From: "Darrius \"Junto\" Thompson" <[email protected]>
To: <[email protected]>
Subject: [OpenDivX] OpenDivX Encoder -> OpenDivX

Daily OpenDivX Encoder Forum Digest

Topic:		Does anybody want this?
Author:		czw
Posted:		 2001-02-21 18:07
I happen to have some free time right now. Instead of spending it on
something constructive, like drinking beer, I decided to come up with
two ideas for speeding up video encoding: 3DNow assembler code and
distributed encoding.

By converting the critical parts of the encode code to AMD:s 3DNow
instruction set, one would see a speed increase. The same could be done
with SSE(2), but I can't test that since I only have an Athlon and a
K6-3 available.

Distributed encoding sounds even funnier: send unencoded data (in blocks
of about eight seconds) to two or more computers, who perform the video
encoding a and returns the finished DivX  video sequence. This way, you
may almost cut the encoding time in half if you have two equally fast
computers in a network.

Is there some work done on any of these projects, and/or do they sound
good to you? The second project would be great in local area networks
with lots of spare processing power.[ This message was edited by: czw on
2001-02-21 18:07 ]


Message: 5
From: "zap twentyfive" <[email protected]>
To: [email protected]
Date: Thu, 22 Feb 2001 13:12:00 +0100
Subject: [OpenDivX] using mpeg2 decoding hardware for divx decoding


I'm a software engineer working for Philips semiconductors and currently I'm 
looking into porting parts of divx to Philips Trimedia:
and Philips Nexperia:

Both platforms have hardware support for MPEG2 decoding as well as video 
coprocessor units which can do things like filtering and colorspace 

>From the limited MPEG knowledge I have I think I can use parts of the MPEG2 
decoding pipeline for divx accelleration, this includes:
-Variable length decoding
-Run length decoding/Inverse scanning
Then there's the image coprocessor which can do post-processing, it has 4- 
and 6 tap polyphase filters with up to 64 fases.

But again, I could be mistaken. I've been studying some documents on mpeg 
and it looks like mpeg2 and mpeg4 are much alike. But then again there must 
be some big difference between the both since divx is much more compact than 

I would be most thankful for anybody who can give me more insight in this. 
IF my initial ideas are correct I'll be able to make a PCI-card that does 
divx decoding wihout using the CPU, with an output to TV.


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