If you have someone with experience modification RIL and Audio level firmware/kernel Android?
Is it possible to intercept/modify/re-route incoming and outgoing audio streams that run from the modem/to the modem or on the other system levels?
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I am having an issue with sound quality out of Acer Iconia A501 tab with Honeycomb 3.2 installed (ROM Harkon 1.0, KERNEL HoneyVillian 3.7). Unfortunately I didn't test it with the stock ROM.
The problem: voice sound in video/voice chat software (Skype, CSipSimple etc.) is of very poor quality (very low volume and very high amount of background noise, as if i'm talking from a closet). The same is true for various voice recording apps.
The only exception so far is TapeMachine.
If I use a _wired_ mobile phone headset AND record using TapeMachine with AutoGain turned off and Input gain set to +20dB, the voice recording is of very good quality, clear and loud. But with the same headset the sound through Skype Echo Test Service is awful. A strange and a very disappointing thing is that with a built-in mic the same TapeMachine settings do not produce any change in voice quality - it was still awful.
Sound Meter reports my background sound (with the headset) at 40dB when silent and 65-70dB when talking.
My understanding of the issue is that starting with API Level 11 (Honeycomb 3.0) voice/video chat software uses android.media.MediaRecorder.AudioSource.VOICE_COMMUNICATION audio source, which is a "Microphone audio source tuned for voice communications such as VoIP. It will for instance take advantage of echo cancellation or automatic gain control if available. It otherwise behaves like DEFAULT if no voice processing is applied."
And it seems like it's not working very well.
My question is: could somebody, please, develop a hack that would allow tweaking of system wide echo cancellation and automatic gain control settings if that's at all possible?
Or is there any other solution?
Thank you!
Hi everyone,
I'm trying to intercept the incoming and outgoing call audio streams. Since this seems to be a complex topic I did some initial research and tried to think of a way how to approach this problem.
What I've learned:
1. The android system will initiate the call through the RIL system. While setting up the call input and output stream target e.g. microphone and speaker will be specified (routed?).
2. The vendor ril library will ultimately be responsible for initializing and maining communications with the modem.
3. Once the call is established the modem will retrieve and send audio data without allowing higher level hooks or modifications to the streams (e.g. through a Java App)
I also found that for other use cases audio data goes through the vender implemented audio HAL library which normally handles audio streams.
So my question is whether the modem will usually make use of the HAL audio library to record / play its data and whether it is possible to "simply" wrap the vender audio HAL implementation library in order to intercept the voice streams.
Sadly I wasn't able to get solid information about this last problems. Somwhere it was mentioned that certain vendors will bypass the OS completely and directly talk to the recording / playback devices however no statement was made to which chips and models this applies.
After applying the new update of android system of mega 5.8.
All voice chat applications( skype - viber - line -etc) have no sound through the normal speaker or even headphone.
The sound available only through the handsfree loudspeaker.
Any help will be really appreciated.
Hi,
We have two different apps sending audio to the call audio stream. We need to mute the audio from one or the other app, and do this programatically (ie. a third app, written by us, controlling the audio mute/unmute of each of the other two apps).
Is there a way to do this without rooting the phone or using a custom OS?
Thanks
I have made an observation in Android Marshmallow (I know, not the newest, but I still want to find answers to this mystery):
Audio recording (using com.nll.asr) blocks video recording.
Audio recording during phone call is possible.
My question is:
How come (technically) that the telephone application is able to access the microphone simultaneously with the voice recorder, while the camera can not?
What is the technical reason for that?
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Trivial observation: In Android 4.4.2, the audio recorder and torch app keeps the LED on and the ASR voice recorder keeps recording during shutdown.