[theora] Possible interference between two directshow encoder/mux instances

Andrew Bisson Andrew.Bisson at gossinteractive.com
Tue Jul 27 01:10:21 PDT 2010

-----Original Message-----
From: theora-bounces at xiph.org [mailto:theora-bounces at xiph.org] On Behalf
Of Cristian Adam
Sent: 26 July 2010 23:00
To: Andrew Bisson
Cc: theora at xiph.org
Subject: Re: [theora] Possible interference between two directshow
encoder/mux instances

On 26/07/2010 11:59, Andrew Bisson wrote:
> I have an application written in c# which uses two instances of the
> theora encoder in a single filtergraph. Each one is followed by an ogg
> multiplexer for output to separate files. When I run the filtergraph
> smaller video's buffer is intermittently written to the start of the
> larger video's buffer. I am using the latest filters from
> opencodecs_0.84.17338.exe and the smaller video is coming from
> preview filtergraph via a GMFBridge component that connects the
> preview/render graphs. There are currently no clear indications as to
> where the interference is occurring but a previous version using wmv
> encoders did not exhibit this problem so it seems possible that it
> in the encoder/mux. Is it possible that the encoder instances are
> sharing memory that they should not be?
> Thanks,
> Andy

Hi Andy,

I have made a test OpenCodecs version which has a fix in the encoder
(removed a static buffer) Please tell me how this version works for you.

You can download the software from:

theora mailing list
theora at xiph.org

Wow, that was quick! I can confirm that this fully resolves the problem
that I was seeing. 

Many thanks for your prompt reply


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