I am on creating voice report. The user has to submit his voice report and it should simultaneously encode the audio data using Vorbis encoder. Its working fine but
encoding will start after the recording is over.
But I should have to employ the Vorbis encoder on the fly. Please share any sample code it would be much helpful.
Be more specific about how you record the audio. Do you just get the wav file or you get chunks of data? If latter, why don't you just feed it to the encoder in real time?
Related
I have a Java application that needs to play a few distinct 'sounds/riffs' to indicate status. I would like to know whether it is better to record these as audio files (wav or whatever format) and play them back using the Java audio classes, or whether it would be better to store MIDI data and play them using the Java MIDI classes.
In my case, storage space is not a problem (within reason). I have about 5-8 status that I would like to play different melodies for. Each melody would be 1-3 seconds, consisting of 2-8 notes.
PCM (found within your WAV file) and MIDI are tools for entirely different jobs.
PCM is a way to encode audio, the sound itself. MIDI is a way to encode messages for controlling synthesizes... note on, note off, etc.
If you're playing back music and you don't particularly need high control over what it sounds like (as each system's MIDI synth can sound different), MIDI is an efficient way to encode it. If you need good quality instruments, vocals, etc., you need an actual sound format like PCM in WAV, MP3, AAC, etc.
I need to convert mp4/flv files info mp3 in my Android application, but I don't know C/C++ and Android NDK. Do you know libraries/methods for easy converting on Java? Thank you for anyway.
Your question is how to extract audio from MP4/ FLV files and save as mp3 file. Right ?
Then, very sorry, Android SDK does not provide any API for transformating or track extraction.
Also using available media framework to achieve the same is also not trivial (and even if you do, you will lose portability).
What I would suggest is to use your MP4 & FLV Parser to extract audio track, do transcoding (if audio track is non-mp3), and save the transcoded (if audio track extracted is mp3, then extracted data) data.
Or you can port FFMPEG code base and use the same. This again may be overkill for your small task.
Suppose you just want to extract mp3 track from MP4, then you understand the native mp4 parser and use the APIs for extraction. You may have to replicate some code from stagefright / opencore.
Shash
it's probably irrelevant for you anymore but if some one still need a mp4 to mp3 parser here's an api that can do the job
I need to create an audio streamer for Android. I want it to play MP3(and other formats too if possible). I also want to be able to progressive download the audio. Does anyone knows a good way to do that?
Thanks!
You should start by checking this link: http://developer.android.com/guide/topics/media/index.html
Apparently this is already done for video, since you can specify a URL as the source for your stream.
You also will have to check some references about audio streaming and the size of the buffering you should use, as well as its dependency with the rate at which you're getting data from the stream in question.
I am using the JSpeex API to convert a .wav file into .spx file. Everything goes perfect when tested on desktop; it took only 2 seconds.
Android developer used the same code but it took around 3 minutes to encode the same file on their simulator & phone. Is there any way to reduce this time for encoding? Code used to convert is as follows:
new JSpeexEnc().encode(new File("source.wav"), new File("dest.spx"));
Compression takes time. The better the compression, the longer it takes, and Speex is pretty good compression.
2 seconds of desktop computer time is absolutely ages.
JSpeex is a java implementation. Use a native implementation, ideally use the platform codecs, instead.
On phones, speech is best compressed using AMR - not necessarily the best quality/compression, but most likely hardware accelerated since its the format used by GSM. You can usually get AMR straight from the microphone.
How do you get large WAV files onto an Android device in the first place? If its actually the output of the microphone, consider using AMR as outlined above.
If you need Speex and you have a wav file, then consider sending it to a server for compression.
I'm trying write a java program to send live microphone data over UDP, then receive the data in VLC. I'm basically using the same code as in this post to package up the stream and send them over. When I receive the data in VLC, I get nothing. I see a bunch of input coming in but none of it is interpreted as audio data. It tries to resolve the information as mpga or mpgv, but I'm pretty sure it's being sent as raw audio. Is the problem on VLC's end? Should I configure VLC to receive a specific format? Or is the problem with my program not packaging the data in a way VLC can interpret it?
First thing you should do is capture the live microphone data to a file and figure out exactly what format it is. Then transfer the file to VLC (if that makes sense) to see if VLC can cope with it in that form.
If you are going to use UDP in the long term, you need to be sure that the audio format you are using can cope with the loss of chunks of data in the middle of the audio stream due to network packet loss. If not, you should use TCP rather than UDP.