I wanted to record a sequence of sounds (using 8 channel mic array).
Matlab's audiorecorder system object does not support more than 2 channels async recording.
When I say async, I want to achieve the following:
The user will press some key (handled by event handler gui) it will start the recording and then again user will press a key then the system will save the current recording and user starts with next audio in the sequence.
I can record 8 ch from Matlab using audioDeviceReader system object but for that, I need to call it for each frame so I will have to create a parallel process that will have to communicate with the event handler and the audioDeviceReader.
I don't have much experience will parallel programming? Should I look into audiorecorder's code and see if can be trivially changed to support 8 ch (If that was the case I think they would have already done it). Or write code to spawn a parallel process which exposes record and stop functions wrapping over audioDeviceReader which can interface with event listener similar to audiorecorder? If so how should I proceed?
Well surprisingly removing the num channel error check in the library code worked. :)
Related
Im working on a STM32F411CEU6 using STM32CubeIDE, Im making a library that works whit UART interruption, inside the UART interruption Im using the HAL_GetTick function to keep track of time, when I use this function outside the interruption It work properly, but when I try to use it inside the interruption the uwTick halt.
I understand that uwTick is a global variable that is incremented on interruption, my first guess was that the UART interruption had greater priority over the System tick timer interruption (I'm guessing that this interruption is the one that trigger the uwTick increment), but the System tick timer interruption has a higher interruption in the pinout configuration UI.
What is going on?
Should I change my approach and use a timer (reading the counter inside)?
additional information:
-Im triggering the interruption whit the HAL_UART_Receive_IT(&huartx, &USART_receive[0], 1), where USART_receive is a receive buffer
-The function that use the HAL_GetTick function is being call in the void USART1_IRQHandler(void) handler after the HAL_UART_IRQHandler(&huart1) function
Thanks in advance!
A higher interrupt priority is represented by a lower number and vice-versa. Maybe you need to switch the priorities around to do what you want.
However, please note:
It is conventional for systick to be one of the lowest priority interrupts in the system, with only pendsv/svcall lower.
It is generally considered a bad idea to try to delay within an interrupt, especially for several milliseconds. It is probably better to set a flag or something in the interrupt and let your main context carry out the delayed action.
I am new to STM32 and freertos. I need to write a program to send and receive data from a module via UART port. I have to send(Transmit) a data to that module(for eg. M66). Then I would return to do some other tasks. once the M66 send a response to that, my seial-port-receive-function(HAL_UART_Receive_IT) has to be invoked and receive that response. How can I achieve this?
The way HAL_UART_Receive_IT works is that you configure it to receive specified amount of data into given buffer. You give it your buffer to which it'll read received data and number of bytes you want to receive. It then starts receiving data. Once exactly this amount of data is received, a callback function HAL_UART_RxCpltCallback gets called (from IRQ) where you can do whatever you want with this data, e.g. add it to some kind of queue for later processing in the task context.
If I was to express my experiences related to working with HAL's UART module is that it's not the greatest one for generic use where you don't know the amount of data you expect to receive in advance. In the case of M66 modem you mention, this will happen all the time.
To solve this you have two choices:
Simply don't use HAL functions at all in case of UART, other than the initialization functions. Implement your own UART interrupt handler (most of the code can be copied from handler in HAL) where upon receiving data you place received bytes in a receive byte queue handled in your RTOS task. In this task you implement protocol parsing. This is the approach I use personally.
If you really want to use HAL but also work with a module that sends varying amount of data, call HAL_UART_Receive_IT and specify that you want to receive 1 byte each time. This will work, but will be (potentially much) slower than the first approach. Assuming you'll later want to implement some tcp/ip communication (you mentioned M66 GPRS module) you probably don't want to do it this way.
You should try the following way.
Enable UARTX Rx interrupt in NVIC.
Set Interrupt priority.
Unmask Interrupt request in EXTI.
Then use USARTX Interrupt Handler Function Define in you Vector.
Whenever the data is received from USARTX this function get automatically called and you can copy data from USARTX Receive Data Register.
I would rather suggest another approach. You probably want to archive higher speeds (lets say 921600 bods) and the interrupt way is fat to slow for it.
You need to implement the DMA transmition with the data end detection features. Run your USART in the DMA mode in the circular mode. You will have two events to serve. The first one is the DMA end of thransmition interrupt (then you copy the data from the current tail pointer to the end of the buffer to avoid data override) and USART IDLE interrupt - this will detect the end of the receive.
This question already has an answer here:
Synthesia plays well midi file without any note off event?
(1 answer)
Closed 5 years ago.
I made a system that takes MIDI files and creates a graphical representation of the music.
Every NoteOnEvent is when a single note starts, and every NoteOffEventwith the same note code is when it ends.
This works well for most MIDI files.
However, I am now encountering files that do not have NoteOffEvent events at all, and so I keep playing them.
What is the correct behavior when seeing for example:
midi.NoteOnEvent(tick=0, channel=0, data=[65, 127])
midi.NoteOnEvent(tick=240, channel=0, data=[65, 0])
I think if a note "on" event happens on the same note it should be like a toggle event, but I am not sure what if it is justified, or does this even happen for every midi file or just a subset that act like this?
EDIT:
I don't think this matters, but I am using python-midi to extract the tracks from midi files
It is common for a note on with 0 velocity to be interpreted as note off. I am not sure if it's part of the standard or not.
I am modifying Apple's code from the AurioTouch2 example on their developer's site. Currently I am trying to fully understand the function of the App. I see that the App writes 0's to the buffers using the silenceData method when mute is on. However, it seems to me that the data has already been processed and when using the App I see no difference wether mute is on or off. What an I missing - what purpose does mute serve?
from the end of performThu method (the input callback)
if (THIS->mute == YES) { SilenceData(ioData); }
from aurioHelper.ccp
void SilenceData(AudioBufferList *inData)
{
for (UInt32 i=0; i < inData->mNumberBuffers; i++)
memset(inData->mBuffers[i].mData, 0, inData->mBuffers[i].mDataByteSize);
}
AurioTouch2 Sample Code
You are correct, all that's doing is zero-ing out the buffer. The reason it's important, is that it's possible for the mData member to be uninitialized (i.e. random), which would result in horribly loud buzzing noises if it was left alone. It's possible that it would make no difference, but you shouldn't really leave that to chance.
If you're ever in a situation where you'd like to produce silence, make sure you 0 your buffer (instead of just leaving it).
First, I found that the mute button does work. When I hold the phone up to my ear I can hear that the sound from the mic is being played through to the receiver. With mute off there is no sound. Before, I was expecting sound from the speaker (not the receiver). That part of the problem solved.
Second, the remote io unit puts the microphone input data in the ioData buffers. Before I was expecting that there would be another callback for the output to the speaker, but I think because there is not one the remote io unit just uses the same ioData and plays it out the receiver (speaker). Thus zeroing out the ioData (after processing the the microphone input data for use by the app) results in silence at the reciever(i.e. the mute function). Any confirmation or clarification is appreciated.
Hi all
I wrote a short program that displays an avi file. I need the program to get input from the keyboard while the movie is running (and not after it ends):
this is my code:
figure('MenuBar','none')
set(gcf,'Color', 'white')
set(gca,'Color','white');
set(gca,'XColor','white');
set(gca,'YColor','white');
m=aviread('c:/t1.avi')
a=30:1:100;
b=100:-1:30;
c=[a b a b a b a b a b] %to run the movie back and forth
movie(m,c) %runs the movie
Thank you for any help
Ariel
Maybe you can insert your video in an UIPanel (or another suitable GUI item) and use the KeyPressFcn callback.
Have a look on this : Callback Sequencing and Interruption (I don't know if it can works but it's probably worth trying).
As far as I know multi-threading or parallel processing capabilities in MATLAB are limited; however it appears as there are remedies. This article describes combining MATLAB and C++ code, with use of MEX files.
Now I have to admit that I have never tried this so I can't really claim that it would work in your case, but it would be a good place to start.
Unless movie() has been designed to watch for input I think you will have to multithread, which from one of the other answers sounds a bit complicated.
You could play a short section of the video, then run come code to check for inputs and then play the next bit of the video. I'm not sure if you can count on things that the user types whilst the video plays going into the input buffer though.
the solution is to use winopen('c:/filename.avi')
winopen('c:/filename.avi')
this command opens media player and runs following commands in the matlab script. it doesn't wait for the movie to end. it runs in the background.
thanks every one
ariel