Rockbox General > Rockbox General Discussion

VU Meter in FM radio (Sansa Fuze v2)

(1/1)

Datman:
May I use VU Meter in FM radio without recording? I've tried to put %pm in a .fms, but I see only the scale dots. How can I send radio audio to the VU Meters? I've found very few info's about VU Meters in the manual...

It needs an A/D converter, then it have to be similar to a stand-by radio recording but displaying the radio screen.

pixelma:
On the software codec targets (anything other than the currently supported Archos devices), the signals take a different route in radio "mode" (from the tuner chip to your headpones) and there just is no data for drawing the peakmeters correctly in the radio screen.

I'm not sure but I think that with the current system it's not possible to change that.

gbl08ma:

--- Quote from: pixelma on January 22, 2011, 04:04:22 AM ---I'm not sure but I think that with the current system it's not possible to change that.

--- End quote ---

AFAIK, if the system was changed to take FM audio to software (like it does while recording) and only then sent to headphones/line out, it would be possible to draw VU meters as well as use any other thing that analyses the audio. But, this implementation would take more resources (CPU at least), and the audio quality would be worse (at least, this is what I've read on another thread).

Apart from this problem - and this is just brainstorming - having FM chip send output to software instead of directly to the headphones could (eventually) open the doors to other fancy features, such as pausing the live emission (the emission gets saved on music buffer until it is full), rewind the emission (again, the emission would have to be constantly saved on the buffer) and fast-forward it (this would imply that the emission is not live, and already stored on the buffer - something that would happen when you pause the emission). To resume, perhaps (just a possibility, need developer feedback on this) it would be possible to implement timeshift functions (like what happens on many DTV tuner and recorder boxes, but this would be for FM radio).

[end of brainstorming]

Datman:
In FM radio analog audio comes from the tuner chip, then it doesn't require CPU power. Do you agree?
CPU only have to send frequency data when it is changed. For the VU meter function audio have to be sent to the analog input and converted to drive the VU meter. The same audio analog signal can go straight to the headphone amp.

Navigation

[0] Message Index