NewLC - Streaming audio input frame size implications - Comments

Re: Streaming audio input frame size implications

raghav_an — Mon, 31 Dec 2007 06:20:43 +0100

Hi,

The "ReadL()" method copies the data from H/W buffer (buffer used by DevSound and lower layers) to the user specified descriptor. The size of the buffer used by DevSound is platform and format dependent. I suppose the size of this buffer can not be chosen by the application.
It would be better to use frames of size same as size of the DevSound buffer.

If you are working on S60 V3, you can use "CErrorConcealment" custominterface to get data in frames rather than in buffers of multiple frames. However, I am not sure whether frame mode can be enabled for PCM record.

Re: Streaming audio input frame size implications

tunelabguy — Fri, 07 Dec 2007 20:57:43 +0100

inguvasheshu wrote:

you should maintain big buffers before operating on data. something like 5*4096 which is a multiple of 320 and 256. from which its easy to segment data and pack them out.

This will not work. If I deal only with big buffers, then I will have terrible latency. My application requires immediate analysis of the sound for feedback to the user. It is a piano tuning application. If the latency is more than 100 msec., then the user will complain that the device is reacting too slowly.

Robert Scott
Real-Time Specialties

Re: Streaming audio input frame size implications

sergiosnok — Tue, 17 Oct 2006 13:43:54 +0200

thank you!

Re: Streaming audio input frame size implications

inguvasheshu — Thu, 12 Oct 2006 07:26:12 +0200

you should maintain big buffers before operating on data. something like 5*4096 which is a multiple of 320 and 256. from which its easy to segment data and pack them out. Every time you get some data from MaiscBufferCopied, you need to add it to this buffer and from another thread you can dispatch the data.

Regards,
Sheshu Kumar Inguva.

Re: Streaming audio input frame size implications

sergiosnok — Wed, 11 Oct 2006 11:01:15 +0200

Hello all, please I'm trying same think using Nokia N70 and it allways return 256 bytes (MaiscBufferCopied), someone has same behavior?
And someone have test N70 phone and Nokia Audio Stream Example?

Re: Streaming audio input frame size implications

tunelabguy — Sat, 23 Sep 2006 18:47:50 +0200

Quote from: mudhalvan

Â Â Â Â Please refer to some of the previous posts by Andrew.hayes. Those are really good one. Those posts should help you a lot in understanding the frame size and their behaviour.

I have seen those postings, and they refer to FP2 and FP3 phones and to other codecs besides PCM. But I can tell you that the native frame size for streaming PCM input in a Nokia 6620 (Symbian 7.0s) is 2048 samples at 8000 samples per second.

Robert Scott
Ypsilanti, Michigan

Re: Streaming audio input frame size implications

mudhalvan — Thu, 21 Sep 2006 17:09:13 +0200

Hi,

Please refer to some of the previous posts by Andrew.hayes. Those are really good one. Those posts should help you a lot in understanding the frame size and their behaviour.

Streaming audio input frame size implications

tunelabguy — Fri, 15 Sep 2006 05:28:45 +0200