Audio Record Limitation

Legato Application Framework
1

Hello, I’m working on a project whereby we are playing audio files over the MDM connection to who we called. We have setup a Recorder to record the received modem audio to a file. I have noted on the page below that there is a limitation where the recorder cannot record both the MDM Rx audio and the MDM Tx audio (which is the audio file being played):

Audio - Legato Docs

Is there any way around this limitation via either software or hardware? We are running with 19.11.3 legato release on WP7611 chipset. Thanks.

2

have you tried the AT!AVAUDIO command?

Can you elaborate more on the use case?

do you mean you want to record the voice call?

3

Hi, thanks for suggestion.

I tried the AT command on WP7611 and it failed when my application was running. I ran my regular application which calls my cell phone, and plays some pre-recorded audio files. I was hoping that I could record the entire conversation to file (both the audio files that were playing along with my responses spoken to my cell phone).

root@swi-mdm9x28-wp:~# microcom /dev/ttyAT
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR
AT
OK
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR
AT!AVAUDIO=4,1,/usr/recording1.wav
ERROR

Using legato le_audio api, I have only been able to record the incoming audio from modem voice call, not the audio we are broadcasting outbound. I was hoping to have both channels of audio in one file.

4

I think you should put the recording in /tmp folder:

AT!AVAUDIO=4,1,/tmp/recording1.wav
OK
at!avaudio=3,1,/tmp/0-to-9.wav
OK
at!avaudio=3,0
OK
at!avaudio=4,0
OK

But I don’t think you can record both the audio file playing and the voice call together.

5

After using the new filepath that is writeable, I was able to get an OK response from the AT!AVAUDIO command but the only thing it did was create an empty wav file with header. There was no audio content. I’m thinking since the legato code of our app had active audio streams that it was the reason that an empty file was created? Are there finite amount of resources that can be used for audio streams or can there be duplicate streams going to different destinations?

6

I did the following and I can record the voice call.


atd1234567;
OK

CONNECT
AT!AVAUDIO=4,1,/tmp/recording1.wav
OK
at!avaudio=4,0
OK
ath
OK