BIOS PSP realtime audio rendering issue

Paul Isaac

Other Parts Discussed in Thread: OMAPL138

Hi,

I'm working on OMAPL138 evm ,my requirement is to develop a low delay audio application with real time capture and rendering.

(Taking input from LineIn and output is giving to LineOut).For this I modified the audio sample application that I got as a part of pspdriver package.

In that sample application I just modified the following things

*sampling rate = 48000.

*BUFLEN = 128.

*NUM_BUFS = 2.

*Initial buffer issue reclaim order.

I'm attaching the source file here :

5187.audioSample_io.c

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/*
 * audioSample_io.c
 *
 * This file contains the test / demo code to demonstrate the Audio component 
 * driver functionality on DSP/BIOS 5.
 *
 * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
 *
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 *    Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

/*
 * audioSample_io.c
 *
 * This file contains the test / demo code to demonstrate the Audio component 
 * driver functionality on DSP/BIOS 5.
 *
 * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/
 *
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 *    Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the
 *    distribution.
 *
 *    Neither the name of Texas Instruments Incorporated nor the names of
 *    its contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 *  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 *  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 *  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 *  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
*/


/** \file     audioSample_io.c
 *
 *  \brief    sample application for demostration of audio playing
 *
 *  This file contains the implementation of the sample appliation for the
 *  demonstration of audio playing through the audio interface layer.
 *
 *             (C) Copyright 2009, Texas Instruments, Inc
 */

/* ========================================================================== */
/*                            INCLUDE FILES                                   */
/* ========================================================================== */

#include "stdio.h"
#include "std.h"
#include "sio.h"
#include "iom.h"
#include "mem.h"
#include "log.h"
#include "ti/pspiom/platforms/evmOMAPL138/audio/Audio.h"
#include "ti/pspiom/mcasp/Mcasp.h"
#include "ti/sdo/edma3/drv/edma3_drv.h"

/* ========================================================================== */
/*                          IMPORTED VARIABLES                                */
/* ========================================================================== */

extern Int edma3init();
extern EDMA3_DRV_Handle hEdma[];
extern LOG_Obj trace;

/* ========================================================================== */
/*                          MACRO DEFINITIONS                                 */
/* ========================================================================== */

/*
 * Buffers placed in external memory are aligned on a 128 bytes boundary.
 * In addition, the buffer should be of a size multiple of 128 bytes for
 * the cache work optimally on the C6x.
 */
#define BUFLEN                  128         /* number of samples in the frame */
#define BUFALIGN                128 /* alignment of buffer for use of L2 cache */


/** Number of serializers configured for record */
#define RX_NUM_SERIALIZER       (1u)
#define TX_NUM_SERIALIZER       (1u)

#define BUFSIZE                 (BUFLEN * sizeof(Ptr))

#define NUM_BUFS                2   /* Num Bufs to be issued and reclaimed */

/* inStream and outStream are stream handles created in main */
static SIO_Handle inStream, outStream;

/* Function prototype */
static Void createStreams();
static Void prime();

Ptr buf[NUM_BUFS * 2];

Mcasp_HwSetupData mcaspRcvSetup = {
        /* .rmask    = */ 0xFFFFFFFF, /* All the data bits are to be used     */
        /* .rfmt     = */ 0x000080F0, /*
                                       * 0 bit delay from framsync
                                       * MSB first
                                       * No extra bit padding
                                       * Padding bit (ignore)
                                       * slot Size is 32
                                       * Reads from DMA port
                                       * NO rotation
                                       */
        /* .afsrctl  = */ 0x00000000, /* burst mode,
                                       * Frame sync is one bit
                                       * Rising edge is start of frame
                                       * externally generated frame sync
                                       */
        /* .rtdm     = */ 0x00000001, /* slot 1 is active (DSP)               */
        /* .rintctl  = */ 0x00000003, /* sync error and overrun error         */
        /* .rstat    = */ 0x000001FF, /* reset any existing status bits       */
        /* .revtctl  = */ 0x00000000, /* DMA request is enabled or disabled   */
        {
             /* .aclkrctl  = */ 0x00000000,
             /* .ahclkrctl = */ 0x00000000,
             /* .rclkchk   = */ 0x00000000
        }
} ;

Mcasp_HwSetupData mcaspXmtSetup = {
        /* .xmask    = */ 0xFFFFFFFF, /* All the data bits are to be used     */
        /* .xfmt     = */ 0x000080F0, /*
                                       * 0 bit delay from framsync
                                       * MSB first
                                       * No extra bit padding
                                       * Padding bit (ignore)
                                       * slot Size is 32
                                       * Reads from DMA port
                                       * NO rotation
                                       */
        /* .afsxctl  = */ 0x00000000, /* burst mode,
                                       * Frame sync is one bit
                                       * Rising edge is start of frame
                                       * externally generated frame sync
                                       */
        /* .xtdm     = */ 0x00000001, /* slot 1 is active (DSP)               */
        /* .xintctl  = */ 0x00000007, /* sync error,overrun error,clK error   */
        /* .xstat    = */ 0x000001FF, /* reset any existing status bits       */
        /* .xevtctl  = */ 0x00000000, /* DMA request is enabled or disabled   */
        {
             /* .aclkxctl  = */ 0x00000000,
             /* .ahclkxctl = */ 0x00000000,
             /* .xclkchk   = */ 0x00000000
        },

};


/* McBsp channel parameters                                  */
Mcasp_ChanParams  mcasp_chanparam[Audio_NUM_CHANS]=
{
    {
        0x0001,                    /* number of serialisers      */
        {Mcasp_SerializerNum_12, }, /* serialiser index           */
        &mcaspRcvSetup,
        TRUE,
        Mcasp_OpMode_TDM,          /* Mode (TDM/DIT)             */
        Mcasp_WordLength_32,
        NULL,
        0,
        NULL,
        NULL,
        1,                        /* number of TDM channels      */
        Mcasp_BufferFormat_1SER_1SLOT,
        TRUE,
        TRUE
    },
    {
        0x0001,                   /* number of serialisers       */
        {Mcasp_SerializerNum_11,},
        &mcaspXmtSetup,
        TRUE,
        Mcasp_OpMode_TDM,
        Mcasp_WordLength_32,      /* word width                  */
        NULL,
        0,
        NULL,
        NULL,
        1,                        /* number of TDM channels      */
        Mcasp_BufferFormat_1SER_1SLOT,
        TRUE,
        TRUE
    }
};

Audio_ChannelConfig audioChanParamsIN =
{
    /*  channel 0 (RX)                         */
    (Ptr)&mcasp_chanparam[0], 
    {   /* codec [0]                           */
        {
            48000,  /* sampling rate for codec */
               0,  /* gain (%) for codec      */
             0x00,
             0x00
        }
    }
};

Audio_ChannelConfig audioChanParamsOUT =
{        
    /*  channel 1 (TX)                         */
    (Ptr)&mcasp_chanparam[1],      
    {
        /* codec [1]                           */
        {
             48000,  /* sampling rate           */
               100,  /* gain (%) for codec      */
             0x00,
             0x00
        }
    }
};

/*
 * ======== createStreams ========
 */
static Void createStreams()
{
    SIO_Attrs sioAttrs;

    sioAttrs       = SIO_ATTRS;
    sioAttrs.nbufs = NUM_BUFS;
    sioAttrs.align = BUFALIGN;
    sioAttrs.model = SIO_ISSUERECLAIM;

    mcasp_chanparam[0].edmaHandle = hEdma[0];
    mcasp_chanparam[1].edmaHandle = hEdma[0];
    
    printf("Stream Create function\n");

    /* open the I/O streams */
    outStream = SIO_create("/dioAudioOUT", SIO_OUTPUT, BUFSIZE, &sioAttrs);

    if (outStream == NULL)
    {
        LOG_printf(&trace,"\r\nCreate output stream FAILED.\n");
        return;
    }

    inStream = SIO_create("/dioAudioIN", SIO_INPUT, BUFSIZE, &sioAttrs);

    if (inStream == NULL)
    {
        LOG_printf(&trace,"\r\nCreate input stream FAILED.\n");
        return;
    }
}

/*
 * ======== prime ========
 */
static Void prime()
{
    Int32        count = 0;

    /* Allocate buffers for the SIO buffer exchanges                          */
    for(count = 0; count < (NUM_BUFS ); count ++)
    {
        buf[count] = (Ptr)MEM_calloc(0, BUFSIZE * RX_NUM_SERIALIZER, BUFALIGN);
        if(NULL == buf[count])
        {
            LOG_printf(&trace,"\r\nMEM_calloc failed.\n");
        }
    }
    /* Allocate buffers for the SIO buffer exchanges                          */
    for(count = NUM_BUFS; count < (NUM_BUFS * 2); count ++)
    {
        buf[count] = (Ptr)MEM_calloc(0, BUFSIZE * TX_NUM_SERIALIZER, BUFALIGN);
        if(NULL == buf[count])
        {
            LOG_printf(&trace,"\r\nMEM_calloc failed.\n");
        }
    }   

    for(count = 0; count < NUM_BUFS; count ++)
    {
        /* Issue the first & second empty buffers to the input stream         */
        SIO_issue(inStream, buf[count], BUFSIZE * RX_NUM_SERIALIZER, NULL);
    }

}

/*
 * ======== echo ========
 * This function copies from the input SIO to the output SIO. You could
 * easily replace the copy function with a signal processing algorithm.
 */
Void Audio_echo_Task()
{
    volatile int i32Count;
    Int nmadus = 0;
    Ptr rcv,xmt;
    Int count = 2;

    /* initialise the edma library                                            */
    edma3init();

    /* Call createStream function to create I/O streams                       */
    createStreams();

    /* Call prime function to do priming                                      */
    prime();


    do{
    	   /* Reclaim full buffer from the input stream */
           nmadus = SIO_reclaim(inStream, (Ptr *)&rcv, NULL);
           if (nmadus < 0)
           {
               LOG_printf(&trace,"\r\nError reclaiming full buffer from the input stream\n");
           }
           memcpy(buf[count],rcv,BUFSIZE * RX_NUM_SERIALIZER);
    
           /* Issue full buffer to the output stream */
           if (SYS_OK != SIO_issue(outStream, buf[count], BUFSIZE * TX_NUM_SERIALIZER, NULL))
           {
               LOG_printf(&trace,"\r\nFailed to issue empty buffer to stream\n");
           }
    
           /* Issue an empty buffer to the input stream                          */
           if (SYS_OK != SIO_issue(inStream, rcv, BUFSIZE * RX_NUM_SERIALIZER, NULL))
           {
               LOG_printf(&trace,"\r\nFailed to issue empty buffer to stream\n");
           }          
           count++;
           
    }while(count < 4);
  
    /* Forever loop to continously receviec and transmit audio data           */
    for (i32Count = 0; i32Count >= 0; i32Count++)
    {
        nmadus = SIO_reclaim(inStream, (Ptr *)&rcv, NULL);
        
        /* Reclaim full buffer from the input stream                          */
        if (nmadus < 0)
        {
            LOG_printf(&trace,"\r\nError reclaiming full buffer from the input stream\n");
        }

        /* Reclaim empty buffer from the output stream to be reused           */
        nmadus = SIO_reclaim(outStream, (Ptr *)&xmt, NULL);
        if (nmadus < 0)
        {
            LOG_printf(&trace,"\r\nError reclaiming empty buffer from the output stream\n");
        }

        /* copy the receive information to the transmit buffer                */
        memcpy(xmt,rcv,BUFSIZE * RX_NUM_SERIALIZER);

        /* Issue full buffer to the output stream                             */
        if (SYS_OK != SIO_issue(outStream, xmt, BUFSIZE * TX_NUM_SERIALIZER, NULL))
        {
            LOG_printf(&trace,"\r\nFailed to issue empty buffer to stream\n");
        }

        /* Issue an empty buffer to the input stream                          */
        if (SYS_OK != SIO_issue(inStream, rcv, BUFSIZE * RX_NUM_SERIALIZER, NULL))
        {
            LOG_printf(&trace,"\r\nFailed to issue empty buffer to stream\n");
        }
    }
}

For this application I measured the delay between first input sample and first output sample(using oscilloscope),its found to be

4.5 milliseconds, but the delay I'm expecting is just over 2.6 milliseconds(i.e,time to fill 128 samples in 48000 Hz sampling rate + Time for one memcopy)

I analysed the code part for EDMA processing, McASP and codec initialization,but I cannot figure out the reason for extra delay.

I'm suspecting is there any inherent delay in driver modules(EDMA3 lld and bios psp),can anyone suggest a solution for this.

Any suggestions will be appreciated...

over 13 years ago

0 Rahul Prabhu over 13 years ago

TI__Guru** 116020 points

Paul,

Here are some suggestions to tuning the audio latency. The wiki was create for C6747 devices but the suggestions made should apply to the OMAPL138 PSP driver as well.

http://processors.wiki.ti.com/index.php/Tuning_Audio_Latency_on_C6747

Basically the wiki makes recommendations to reduce the number of McASP buffer used for buffering, makes suggestions for tradoff between performance and buffer Size and recommends disabling of MCASP FIFO so that audio data is directly moved by the EDMA without requiring it to be moved in the FIFO.

Hope this helps.

Regards,

Rahul

0 Paul Isaac over 13 years ago in reply to Rahul Prabhu

Intellectual 340 points

Hi Rahul,

Thanks very much for your quick reply. That link was really helpful.

I disabled the FIFO in McASP, and got a reduction around 1.2milli seconds :)

Regards,

Paul

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BIOS PSP realtime audio rendering issue