I used LAME to encode wav to mp3 in android succesfuly. now i want to encode it in real time during the caputure of the pcm sample (meaning to pass the buffer insted of the file), is it possible using LAME to do it or i need to write new function for it?
http://lame.sourceforge.net/ - LAME
Related
Since MediaRecoreder not supports encoding to mp3 format.
Can ffmpeg to record audio directly from Android audio source (how to specify this) or it only encodes one file to other format?
You mean using Android to record audio and save it as mp3?
If so, you can code mp3 using libmp3lame. And this is very useful.
Since Android Record outputs a pcm, liblmp3lame can use pcm as input and then output mp3 data.
Is it possible to record the internal sound generated by the app?
My app allows you to create and play back musical sequences.
soundPool.play(soundIds[i], 1f, 1f, 1, 0, Constants.TIME_RATE);
I'd like to be able to record the sequence and export to mp3.
I've looked into Audio Capture but setAudioSource (int audio_source) only seems to accept MIC recording.
Thanks
No, there's no API for getting the audio output, even for your own app (actually that's not entirely true, because you can get it through the Visualizer API, but it would be of such low quality that I doubt it would be of any use for you).
If you want that kind of functionality you'll have to implement it yourself. That is; as you start playback of sounds, mix them and write the result to a file as well. If the sounds are compressed you'll also have to take case of decoding them yourself.
Note that there's no MP3 encoder included with Android, so you'd have to supply your own MP3 encoder anyway if that's the format you want to export in.
As the michael said , u need to implement your own encoder and decoder for that . Visualizer is providing very low quality of data becaz we can use it to show on custom views and effects which are synchronized with equalizer.
This is the link where u will find simple decoder and encoder for MP3 file. Where they are reading data from MP3 file and putting it into new MP3 file. They had created support for some other extension too.
http://code.google.com/p/ringdroid/source/browse/#svn%2Fbranches%2Fgingerbread%2Fsrc%2Fcom%2Fringdroid
According to http://xzpeter.org/?p=254 it's possible to capture internal sound playback if you modify Android sources. Particularly the write function of the AudioFlinger::MixerThread class. (Note that the article is a little bit old - on the latest Android versions AudioFlinger was reorganized and write code can be now found in the threadLoop_write() function).
Quoting original solution author:
AudioFlinger is implemented under dir
frameworks/base/services/audioflinger/. What we are going to
do is to find the mixer output. In the file AudioFlinger.cpp, we can
see AudioFlinger::MixerThread::threadLoop(), which is the working
thread of the mixer, and this MixerThread is inherited from
AudioFlinger::BaseThread. Then, just search the keyword mOutput->write
with your best editor (vim, emacs, gedit, whatever), and we will find
something like this under the threadLoop() function:
mLastWriteTime = systemTime();
mInWrite = true;
mBytesWritten += mixBufferSize;
int bytesWritten = (int)mOutput->write(mMixBuffer, mixBufferSize);
if (bytesWritten < 0) mBytesWritten -= mixBufferSize;
mNumWrites++;
mInWrite = false;
That is the very point that mixer output buffer is transferred to hardware related codes I think, and the audio clip is in mMixbuffer, with size mixBufferSize. In this buffer, there are PCM raw audio data with 44100Hz sampling rate, 2 channels and 16 bits little endian as its param.
If you write this buffer out to a file, like /data/wav.raw, you can just use adb pull to retrieve the data file to your host machine and play it with aplay:
aplay -t raw -c 2 -f S16_LE -r 44100 wav.raw
Anyway, in order to convert it to mp3 you will have to use external encoder as stated by Michael.
I'm developing an audio processing application where I need to record audio, and then process it to obtain features of that recording. However, I want the audio in a playable format to play it after with MediaPlayer.
I've seen that to record audio to process it it's better to use AudioRecord, because I can get the raw audio from there. But then I can't write the data to a file in a playable format (is there any library to do this in android?).
I used this method to record raw data and then write it into a file:
http://andrewbrobinson.com/2011/11/27/capturing-raw-audio-data-in-android/
But when i try to play this file on the device, it is not playable.
Then if I use MediaRecorder I don't know how to decode the data to extract the features. I've been looking at MediaExtractor, but it seams that MediaExtractor doesn't decode the frames.
So.. what's the best way to do this? I imagine that's common in any audio processing application, but I wasn't able to find the way to manage this.
Thanks to your replies.
Using AudioRecord is the right way to go if you need to do any kind of processing. To play it back, you have a couple options. If you're only going to be playing it back in your app, you can use AudioTrack instead of MediaPlayer to play raw PCM streams.
If you want it to be playable with other applications, you'll need to convert it to something else first. WAV is normally the simplest, since you just need to add the header. You can also find libraries for converting to other formats, like JOrbis for OGG, or JLayer for MP3, etc.
For best quality result you have to use AudioRecord class instead of MediaRecorder.
Please have a look to below link:
Need a simple example for audio recording
Also have a look to this link: http://i-liger.com/article/android-wav-audio-recording
If you use AudioRecord object to get the raw audio signal, the next step to save it save as a playable file is not so difficult, you just need to add a WAV Head before the audio data you capture, then you get a .WAV file which you can play it on most mobile phones.
A .WAV file is a file under the RIFF format. the RIFF header for WAV file is 44 byte long and contains the sample rate, sample width and channel counts information. you can get the detail information from here
I did the sample function on Android phones and it worked.
I tried to record audio in Android. The quality of the sound using the MediaRecorder really sucks.
So I tried writing the sound to a stream using the AudioRecord function. Great quality but pcm-files are too large in size as I want to upload them to a remote server.
Does anybody know how to compress the pcm (like mp3 or else)?
Any help is mostly appreciated.
Tom
As far as I know, there are no built-in audio converters in Android. Your best bet is to use third party library, maybe even a c/c++ one.
Look at this question for more info: How to encode a WAV to a mp3 on a Android device
Is there an easy way to merge 2 3gp (amr) audio files into a single audio file?
I need them to be synchronous/over top of each other not one after the other. I am using android to do this. I have heard somewhere that for some audio formats you can simply add the bytes (being careful that you dont get a too high or too low result). Is this true with the 3gp/amr format on android?
Android only allows playback/recording of 3GP/AMR files. To mix audio you will need the decoded PCM data. This means you have to decode both streams mix (this is indeed adding + normalizing) and then playback.
The bad side - there no way to get access to the build in AMR decoder which allows you to decode without playback.
So ... no easy way.