B4A Library Audio library v1.5 - New AudioStreamer object

Discussion in 'Additional libraries, classes and official updates' started by Erel, Jun 26, 2013.

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  1. Erel

    Erel Administrator Staff Member Licensed User

    This version includes a new AudioStreamer type. Note that this is a beta version (for this type only).

    The purpose of AudioStreamer is to make it simple to stream audio from the microphone and to the speakers. Internally it is based on AudioTrack and AudioRecord.

    Next week I plan to create an example of streaming audio between two devices (walkie-talkie app).

    Recording is done by calling StartRecording. The RecordBuffer event will be raised multiple times during the recording:
    Sub streamer_RecordBuffer (Buffer() As Byte)
    'collect the recording data
    End Sub
    You can write this data to a file or as done in this example, collect the buffers in a list. Later we will use this list to play the recording:
    Sub btnPlay_Click
       btnStartRecording.Enabled = 
    For Each b() As Byte In buffers
    Null'when this "message" will be processed, the player will stop.
    End Sub
    Note that the player has an internal queue. The write method will not block the main thread. The data is just added to the queue. It is processed by another thread.


    As this is a beta version, it will be great if you can run the small example and test it on your device...

    An example of saving the recording to a wave file is available in post #10.
    Walkie-Talkie example is available here.

    Installation instructions:
    This library should be copied to the internal libraries folder.

    Unzip the attached file and copy both files to (default):
    C:\Program Files (x86)\Anywhere Software\Basic4android\Libraries

    V1.62 is attached. It adds an Error event. This event will be raised when an error happens during recording.
    New method: AudioStreamer.Initialize2.
    It allows you to set the audio source. The value should be one of the values listed here: http://developer.android.com/reference/android/media/MediaRecorder.AudioSource.html
    For example to set the audio source to the voice call channel you will use the value 4.

    Attached Files:

    Last edited: Sep 6, 2018
  2. Nizze

    Nizze Active Member Licensed User

    Great !!

    To be able to do a walkie-talkie app is a great thing that i have been waiting for a long time to be reality

  3. NJDude

    NJDude Expert Licensed User

  4. drachmad

    drachmad Member Licensed User

    Hi Erel, it is a nice feature.
    I try to download the example but it seem it is not format properly (the Audio.zip is ok)
    Using Chrome like it will never finish, using firefox with Fdm, I can not unzip it.
    And btw the size seem like around 30 KB while in you thread it should be around 7.7 KB?
  5. Erel

    Erel Administrator Staff Member Licensed User

    I've just tried it with FireFox and it opens fine here... I will remove the attachment and upload it again.
  6. drachmad

    drachmad Member Licensed User

    the download name is:
    if it helps.
  7. Erel

    Erel Administrator Staff Member Licensed User

    Are you still unable to download it?

    Are other members able to download?
  8. drachmad

    drachmad Member Licensed User

    Now its working, thanks.
    Your sample works perfectly on Galaxy Tab II 7.
    It give message in the log:
    sending message to waiting queue (streamer_recordbuffer)
    if the screen is going to sleep mode and it stop recording.
    I think it is nicer if there is a sound it will still recording until stop recording is pressed
    or keep the screen alive while the stop recording is not pressed.

    It is possible to give an example to save the stream to a file in the example?
    Last edited: Jun 26, 2013
  9. Erel

    Erel Administrator Staff Member Licensed User

    This is just a simple example. It is better to move the recording code to a service.

    In order to save the stream to a file you should open an OutputStream with File.OpenOutput and then write the bytes with OutputStream.WriteBytes. When the record is complete you should close the file.

    Note that the file will not be a valid wav file because it doesn't include the wav headers.

    To play the file you need to open an InputStream and then read chunks of data from the file. The buffer size used for writing should not be larger than streamer.PlayerBufferSize.
  10. Erel

    Erel Administrator Staff Member Licensed User

    The attached example saves the recording to a wave file. First it creates the wave header. Then the data is saved and the last step is to write two additional fields that depend on the data size.

    This time we use MediaPlayer to play the recorded file.

    This is a good example of using RandomAccessFile to implement a specific file format.

    Attached Files:

  11. drachmad

    drachmad Member Licensed User

    Hi Erel, thanks for the sample.
    When you wrote just add the WAV header, I am lost because all in the B4A has only library for WAV file.
    AudioRecorder Library V1.00 by XverhelstX
    AudioRecord Library V1.01 by stevel05
    Now I think a newbie can see the structure of the WAV header.
    I have change your sample into a service may be it is a good start for a newbie like me to experience with the lib. So that it is easier to combine with other application that needs recording.

    Now the only problem is converting/recording to MP3. It seem in B4A its still not mature the libs or classes.

    Attached Files:

  12. moster67

    moster67 Expert Licensed User

  13. drachmad

    drachmad Member Licensed User

    Hi moster67, thanks.
    I have read that, he himself wrote it is not stable. Thats why I wrote is not mature yet. But thanks anyway.
  14. thedesolatesoul

    thedesolatesoul Expert Licensed User

    Hi Erel,
    Thanks for this :)
    The library docs here are still showing ver 1.32 docs.
    Basic4android - Audio
    omo likes this.
  15. Zeev Goldstein

    Zeev Goldstein Active Member Licensed User

    something must be wrong with me, please do not be angry...
    i still can't figure out how to read a magnetic card using a card reader attached to the audio jack - i must be missing something and it's killing me
    please help
  16. Erel

    Erel Administrator Staff Member Licensed User

    Have you tried to record the "audio" while the card reader is working?
  17. Zeev Goldstein

    Zeev Goldstein Active Member Licensed User

    no i did not as i don't need the recorded audio, i need the text data from the magnetic stripe of the card - the card info
    will it store this data in the file as a text string when i "read/record" the card ?
    thanks so much for your replies and assistance
  18. Zeev Goldstein

    Zeev Goldstein Active Member Licensed User

    did try the audio samples which worked perfectly, recorded my voice and play it.
    i guess it will work when the mic is external and plugged to the audio jack
    however - when going to capture the credit card data i need to have the data only without any "audio" etc
    and i need it not as audio as it is not - it is a text string
    so i am lost again
    any possible sample of capturing credit card data using a reader plugged into the audio jack ?
    thanks once again
  19. Erel

    Erel Administrator Staff Member Licensed User

    Please start a new thread for this question and post any information you find about the protocol used by your reader.
    Zeev Goldstein likes this.
  20. js1234

    js1234 Member Licensed User

    I'm copy Audio.jar and Audio.xml to C:\Program Files\Anywhere Software\Basic4android\Libraries
    but library isn't visible in Library tab!
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