I'm writing a small call-recording application for my rooted phone.
I'm looking for a way to record audio directly from android system - or as low-level as possible, without using standard API's MediaRecorder or AudioRecord.
How can I do this? I can't find any good example on it, although I see it implemented in many apps (that require root).
Related
Hello guys I have a question
I have to admit before I ask my question I never used Android Sdk before but I have coded java for couple of years.
I have a fm radio app.It's an internet radio and I want to record it's output. Is it possible to use an external app to record some other app's output? And if yes, It also has some pre recorded shows which you can listen within the app. They do not get saved into my device when I listen however is it possible to download those shows? Like finding source of the audio and downloading it using my external app.
I'm pretty sure that the recorded shows are downloaded from the internet. I know some audio grabbers as browser extensions in Pc. So I'm asking, if such thing is possible in Android as well.
See below:
https://stackoverflow.com/a/25741006/850347
Seems to be currently there is no way to achieve this. I have read this article and it suggests to recompile the Android source code with some changes.
Or, you can use visualizer.
https://stackoverflow.com/a/25816052/850347
The closest API available to you for these purposes is Visualizer. Which only captures "partial and low quality audio content".
I'm trying to design an Android app that will start a service which applies a reverb (using convolution) to any audio played through the phone regardless of the app the audio is coming from. The service would ideally run in the background and enable the reverb effect as soon as audio begins to play on the device.
Is something like this possible on a non rooted Android device, and if it is, where's the best place to get started?
Thanks
It is not possible without root access.
There is some example of real time convolution such as viper4android fx though it uses linux native driver to achive the problem.
Is it possible and if so "how" would one create a "fake" Camera in an Android application. By "fake" I mean an all software creation that simply looks like a regular Camera to the OS but in actuality takes a Bitmap or byte array as its input data. I want to use such a device with a MediaRecorder to create h.264 videos.
Things this could be used for:
Image slideshow video creation
Screen capture to video file
Caveats: No rooting and no ROM modification
I think what you are looking for is a way to encode videos to H.264 in a way similar to what MediaRecorder does but not from the camera. You do not particularly care whether this is done with a "fake camera" or in some other way, correct? In that case...
You can use the MediaCodec API available in Android 4.1 and later. You can just give it a series of images and it will create video encoded with (where available) the hardware encoder. Some sample code: Create video from screen grabs in android and Encoding H.264 from camera with Android MediaCodec
If you are expecting to affect other apps with your "fake Camera", that is only possible by modifying the Android source code and rolling your own ROM mod.
Yes,you can!
No rooting and no ROM modification,the best way to do this is to build a virtual app that runs the other app as a plugin，so that you can modify anything in the target app. But there is so much work to do, the best news is that there are several open source projects to do this.
And so, the next thing is not so difficult,you only have to hook several libs so in /system/lib that affect the camera recording.
In fact, I have done this on my device, but I modified the system lib directly, it has to be rooted of course. But it works well on almost all apps except some apps that use the service to capture video.
We have to modify the service lib, but it is a little more difficult.
I've been experimenting with making an android app for the past week or two and have reached a point where I need to decide on a general plan of action concerning the code I'm writing.
started with SoundPool, easy to use, not very flexible. went on to AudioTrack, seems good but slow.
So now I'm looking at the ndk..
Does the ndk have direct access to AudioTrack? or something else?
What is the general concensus on this kind of thing?
A guess is to make the UI in java and the 'sound engine' in C++
I'd like to get started on the right track before I write too much.
edit:
It is a music studio that plays and manipulates wav files from the sdcard as well as realtime sound synthesis.
The Android SDK doesn’t offer a fully featured audio processing solution like Core Audio on iOS. The available features are exposed through OpenSL ES interface. Any audio processing feature's availability is dependent on the device manufacturer’s Android flavor and configuration, so you can not rely on them.
To wit, the infamous Android fragmentation problem is even bigger in audio.
Even worse, if a device reports an audio feature available, it may still not work properly. For example: audio playback rate on a Samsung Galaxy Note III.
Realtime sound synthesis? None of the Android SDK’s features are designed for that.
The best way is doing the UI in Java and dealing with sound in C++.
There are some 'audio engine' offers on the web, but many of them are just “wrappers” around the same thing.
As cofounder of Superpowered, allow me to recommend the use the Superpowered Audio SDK, which is a total audio processing solution designed for real-time and highest performance, without any dependency on Android’s audio offerings, and runs on all.
http://superpowered.com/
There are a ton of Audio Latency issues in Android. There's really not anything that can be done about it. It seems like ICS (4.0) may have done some improvements on it, from what I've read.
You could subscribe to Andraudio and you'd actually be better off directing Android Audio questions through their emailing list than through Stackoverflow:
http://music.columbia.edu/mailman/listinfo/andraudio
Is it possible for an android app running in the background to access the sound being produced by a media player (to be used for recording to another file, streaming etc)? Will the app read from the sound port? How will this work if it is possible? Any existing apps?
Appreciate any help/pointers.
No.
Or more precisely: on an unmodified Android device there is no audio loop back or pass through functionality.
http://developer.android.com/reference/android/media/MediaRecorder.AudioSource.html lists all the audio sources available to the MediaRecorder and AudioRecorder classes.
Now, if you are willing to write a device driver and have the capacity to root the target device and load your driver on it you could possibly implement a loop back driver, a pass through driver or (much more interesting) an alternative audio output device that would perform your streaming/recording and then forward to the regular audio output.
To caputre a Sound-Output form the Android Device, you can use the MediaRecorder-class, like shown in this tutorial.
But recording a Sound-File, which already exists (on the SDcard ore something) doesn't make any sense to me.