[mad-user] dual-thread libmad

[Steve Spano]

Hi John,

Thanks for the reply.

I did more tracking into this, the mad_decoder_buffer creates the
instances on the frame/stream/sync data. I already created two instances
of the mad_decoder_buffer so I could link them to each RTOS thread.

It looks like the samples are getting mixed up at the output stage. It
turns out that one of the MP3s playing is a 1-channel and the other MP3
is a 2-channel. Any thoughts perhaps on how mixing of sample data,
between RTOS tasks, could occur on the output stages? 

I figured this part out, that it is occurring at the output stage,
Friday ~ 5pm. I have to look at it some more.

Thanks

Steve Spano, President
Finger Lakes Engineering


-----Original Message-----
From: john cooper [mailto:john.cooper at third-harmonic.com] 
Sent: Friday, December 07, 2007 10:09 AM
To: Steve Spano
Cc: mad-user at lists.mars.org; john cooper
Subject: Re: [mad-user] dual-thread libmad

Steve Spano wrote:

> I have a simple RTOS which has two threads. Each thread starts lib mad

> with a dedicated mad_decoder buffer for each thread. I am now able to 
> "read" data correcting into the decoders (i.e. I don't see decoding 
> errors streaming everywhere on the debug trace) but the output audio
is 
> mixed up. Meaning that the audio from the two threads is being mixed 
> (actually shuffled) during playback.

It is built into the API.  You'll need to keep separate
frame/stream/synth data structures for each instance of
a decode operation.  Sounds like you are rendering to the
same set of structures multiplexed by the task scheduler.

-john

-- 
john.cooper at third-harmonic.com