Hi,

The audio driver on the DM6446 is capable of full duplex operation. The only issue really is that it is stereo only regardless of the ioctl that sets the number of channels.

If you search the Davinci mail list you should find some simple test programs that I posted a while back that can be used to demonstrate the audio capability. If you can't find them then let me know and I will see if I can dig them out again.

The 'garbled' voice could be a symptom of under/overrunning, that is your application has not written enough data in one go to keep the output buffer full of enough data till the next write. Similarly on the read, if you do not empty the input buffer it will fill up and then drop input.

You did not describe how your application 'ticks' to perform the non-blocking operation...you can use SIGALRM to interrupt a select for example (or 'nanosleep' in a loop). You can use the ioctl to check for samples before the read and similarly the output space ioctl before the write. This will prevent the read or write blocking as you simply skip the read or write if no data or space for data is present.

Regards

Phil Q


Venkatachala Upadhya wrote:

Hello all,

I am using DM6446 EVM board. Using DVSDK 1.20.00.10 version. Running gstreamer on the board. I am 
trying to use the device "/dev/dsp" for both recoding and playback simultaneously.  I am 
un-able to do so after setting the device to full-duplex mode using the ioctl call 
"ioctl(soundFd, SNDCTL_DSP_SETDUPLEX );"

If I use the device in non-blocking mode for recording and playback I am getting the 
voicce as garbled. Is "recording and playback simultaneously" possible?
Can any one share the experience?

With best regards,
Venkat.
--

This message (including attachment if any) is confidential and may be 
privileged. If you have received this message by mistake please notify the 
sender by return e-mail and delete this message from your system. Any 
unauthorized use or dissemination of this message in whole or in part is 
strictly prohibited. E-mail may contain viruses. Before opening attachments 
please check them for viruses and defects. While MindTree Limited (MindTree) 
has put in place checks to minimize the risks, MindTree will not be responsible 
for any viruses or defects or any forwarded attachments emanating either from 
within MindTree or outside.

Please note that e-mails are susceptible to change and MindTree shall not be 
liable for any improper, untimely or incomplete transmission.

MindTree reserves the right to monitor and review the content of all messages 
sent to or from MindTree e-mail address. Messages sent to or from this e-mail 
address may be stored on the MindTree e-mail system or else where.

_______________________________________________
Davinci-linux-open-source mailing list
[email protected]
http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source



_______________________________________________
Davinci-linux-open-source mailing list
[email protected]
http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source

Reply via email to