CC3200 WiFi Audio App

Hi Mohammad,

In wifi audio app mDNS service get register on pressing speaker button. Please look SpeakerControl() function in control.c.

Regards,

Aashish

Hi,

since registering of mDNS happens by pressing speaker button, does it mean that the board with the speaker on it advertises the service or listens to it?

and also, I was testing this example in a loopback mode (with only one launchpad), which means there was no WiFi connectivity in test condition. I realized there is a considerable amount of delay in audio, specially when you are looking at a video, such as news, etc. I thought that I can reduce that delay by reducing size of the buffer, but then when I was going below 50% of the default buffer size I was not getting any audio.

Regards,
Mohammad

Hi Mohammad,


Change PLAY_WATERMARK macro value for reducing latency. For more detail refer e2e.ti.com/.../1400223


Regards,
Aashish

Thanks for your response, Aashish. I changed PLAY_WATERMARK macro and saw that the latency was reduced. but there was some issues with it. the default value of this macro is 30*1024, and I can't go below 20*1024, whenever I do go under that value I lose the audio.

and also there is a very annoying problem with the audio coming out of line out. it is not clean audio, I here ticking noise. I don't know where it is coning from.

Regards,
Mohammad

Hi Mohammad,

Mohammadhossein Behgam said:

I changed PLAY_WATERMARK macro and saw that the latency was reduced. but there was some issues with it. the default value of this macro is 30*1024, and I can't go below 20*1024, whenever I do go under that value I lose the audio.

We had tried with 2K watermark without any loosing audio data or issue. Please review changes you made again. May be buffer size of play and record buffer is not enough. 

Mohammadhossein Behgam said:

also there is a very annoying problem with the audio coming out of line out. it is not clean audio, I here ticking noise. I don't know where it is coning from.

Seems like there is buffer underrun issue.

How do you measuring latency?

Regards,

Aashish

Hi Aashish,

I don't actually use any tools to measure latency, I put on a video on youtube which is mostly somebody in front of camera talking, so that I can see his/her mouth, then check if the audio matches with the video.

I did not remember what I had changed in the example so I deleted it from my workspace and imported it again, and I was able to go down to 4*1024, I couldn't go below since I was losing the audio again, and with 4*1024 PLAY_WATERMARK audio and video almost match together, but still my ears detect a very small latency.

however, Importing this example again to my workspace did not solve that ticking noise, and I don't know anything about buffer under-run, can you explain a little more?

Regards,
Mohammad

Hi Mohammad,


Buffer under-run means when there is no data for playback in buffer. In case of under run we are playing 0 that may cause ticking noise. To avoid under-run situation take buffer of enough size. But it will increase latency.

There will be always some latency because of buffering. And we are using buffering for smooth playback else there will be more ticking noise.


Regards,
Aashish

Hi Mohammad,


We are closing this thread, for follow up queries please open a new thread and add a link to this one for reference.


Regards,
Aashish