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OpenDivX digest, Vol 1 #32 - 2 msgs



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Today's Topics:

   1. I want to implement a 2 pass vbr encoder ([email protected])
   2. Re: I want to implement a 2 pass vbr encoder (Andrew Woznytsa)

--__--__--

Message: 1
From: [email protected]
To: [email protected]
Date: Thu, 08 Mar 2001 12:29:22 +0100 (MET)
Subject: [OpenDivX] I want to implement a 2 pass vbr encoder

Hi,

I have a lot of spare time and would like to implement a 2 pass VBR encoding 
algorithm in encore. In order to do that I'm reading this:

http://www.research.ibm.com/journal/rd/434/westerink.html

This document describes an implementation of a 2 pass MPEG-2 vbr encoder. For 
that it first does a first CBR pass, gathering statistics, processes them in 
order to obtain control parameters for the second pass. Then during the second 
pass there is a bitrate control process that takes into account the prediction 
error.

I also grabbed the encore sources and I'm looking into rc_q2.c and rc_q2.h.

I have noticed that the bitrate modelling algorithm in the encore sources is 
not a CBR algorithm but rather an ABR algorithm (Average Bit Rate). In order to 
implement a 2 pass encoder I need to first implement a true CBR rate control, a 
strong one like in MPEG-1 or MPEG-2.

I will go and grab rate control sources for MPEG-1 and MPEG-2 CBR and implement 
them into encore. Then I will implement the statistics processing and VBR 
control process.

I begin in this video compression field but I have a lot of time and I have C 
programming skills on Unix.

Where can I find good documentation about MoMuSys MPEG-4 implementation and 
MPEG-4 standard? Could Adam Li, the author of rc_q2.c help me a little by 
explaining me how it works so that I don't begin at 0.



--__--__--

Message: 2
From: "Andrew Woznytsa" <[email protected]>
To: <[email protected]>
Subject: Re: [OpenDivX] I want to implement a 2 pass vbr encoder
Date: Thu, 8 Mar 2001 13:42:48 +0200

Hi,

Official MPEG4 reference software :
http://isotc.iso.ch/livelink/livelink/fetch/2000/2489/Ittf_Home/PubliclyAvai
lableStandards.htm

there is momosys, ms fdis and some std.(too old, 1998 year.. as i know
updates is not publicly available..).

regards,

Andrew

----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Thursday, March 08, 2001 1:29 PM
Subject: [OpenDivX] I want to implement a 2 pass vbr encoder


> Hi,
>
> I have a lot of spare time and would like to implement a 2 pass VBR
encoding
> algorithm in encore. In order to do that I'm reading this:
>
> http://www.research.ibm.com/journal/rd/434/westerink.html
>
> This document describes an implementation of a 2 pass MPEG-2 vbr encoder.
For
> that it first does a first CBR pass, gathering statistics, processes them
in
> order to obtain control parameters for the second pass. Then during the
second
> pass there is a bitrate control process that takes into account the
prediction
> error.
>
> I also grabbed the encore sources and I'm looking into rc_q2.c and
rc_q2.h.
>
> I have noticed that the bitrate modelling algorithm in the encore sources
is
> not a CBR algorithm but rather an ABR algorithm (Average Bit Rate). In
order to
> implement a 2 pass encoder I need to first implement a true CBR rate
control, a
> strong one like in MPEG-1 or MPEG-2.
>
> I will go and grab rate control sources for MPEG-1 and MPEG-2 CBR and
implement
> them into encore. Then I will implement the statistics processing and VBR
> control process.
>
> I begin in this video compression field but I have a lot of time and I
have C
> programming skills on Unix.
>
> Where can I find good documentation about MoMuSys MPEG-4 implementation
and
> MPEG-4 standard? Could Adam Li, the author of rc_q2.c help me a little by
> explaining me how it works so that I don't begin at 0.
>
>
> _______________________________________________
> OpenDivX mailing list
> [email protected]
> http://lists.projectmayo.com/mailman/listinfo/opendivx


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