VS1053b - Speed of switching between Play and Record

Writing software that inputs and/or outputs audio and performs DSP algorithms such as filters, new codecs or audio effects.
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MoltenVoltage
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VS1053b - Speed of switching between Play and Record

Post by MoltenVoltage » Fri 2017-05-26 5:34

Hi there,

I have a project that requires an audio module that can switch very quickly between playback and record and vice-versa. Can the VS1053b switch seamlessly between the two or does it pause after recording for formatting or other reasons as the other modules I have tested do?

Thanks!

- Bill

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Panu
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Re: VS1053b - Speed of switching between Play and Record

Post by Panu » Fri 2017-05-26 8:36

Hi!

Creating a file is an intensive operation that takes relatively long time, dozens of milliseconds at least. What you need is a device which can play and record simultaneously. Which audio format do you need to support? VS1005 could probably do it, at least with WAV.

What is the definition of "seamless"? Do the play and record sample rates need to be locked together? How about handling of incoming and outgoing sample buffers? If we knew what you were trying to achieve exactly, e.g. what your final application is, we might be able to answer these questions.

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MoltenVoltage
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Re: VS1053b - Speed of switching between Play and Record

Post by MoltenVoltage » Fri 2017-05-26 16:36

Hi Panu,

Thank you for the response.

It sounds like the VS1053b is far too slow.

The application is a "looper" where a musician records audio, then when they stop recording, the device immediately starts playing back that same audio, so yes, the play and record samples must be locked since the playback must begin immediately following recording (or within less and 1ms).

- Bill

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pasi
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Re: VS1053b - Speed of switching between Play and Record

Post by pasi » Fri 2017-07-14 13:42

The storage and its handling will set the limits more than any vs10xx chip, because I think you would want to save in uncompressed format.

In itself, using the DAC and ADC at the same time would not be an issue, vs1063a has a codec mode which does that.

But you're right that with vs1053b you would probably run out of program memory because there is much more than just the audio path. The firmware would need to handle user interface and the storage, and depending on the storage there may be too little data memory to use as buffers to manage the write latencies of the storage.
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MoltenVoltage
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Re: VS1053b - Speed of switching between Play and Record

Post by MoltenVoltage » Fri 2017-07-14 18:55

So can the 1063 record audio then switch to playback mode of that same audio within 1ms?

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pasi
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Re: VS1053b - Speed of switching between Play and Record

Post by pasi » Mon 2017-07-17 11:43

MoltenVoltage wrote:
Fri 2017-07-14 18:55
So can the 1063 record audio then switch to playback mode of that same audio within 1ms?
If you use an external controller to handle the storage and data transfer, and you use PCM WAV (or maybe g.722), you can keep vs1063a in codec mode the whole time and your storage sets the limit of how quickly you can switch.

I would expect that you also want to save the ADC data while you play back the loop? You would be reading data from storage and sending it to vs1063 for playback, and at the same time read the data from vs1063 and writing it to storage. During the first "loop" you would only be writing, not reading.

(We are designing this kind of recorder app for vs1005, although I can't estimate when the first release will come out.)
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