I am working on media recording on IOS. I was able to record with both audio and video using UIImagePickerController. For my specification I want to record only audio. Is it possible with UIImagePickerController? or Do I need to think about other methods?
thanks.
UIImagePickerController cannot be used to record audio. Instead you should take a look at the SpeakHere sample code from Apple.
Also check Audio Queue - Recording to a compressed audio format on how to record as compressed audio format and conserve disk space.
Related
I want to make an app for the iPhone with the ability to record video. One thing I want to do with the video once it's recorded, is to take the audio from it and alter it, such as make it sound feminine or masculine etc. I've never done this before but is it better to use AVFoundation or UIImagePickerController. I've read that the UIImagePickerController is easier to use but will it allow be to extract and edit the audio of the recorded video and put it back in?
Any help or suggestions as to how to approach this are appreciated.
Thanks
It is easiest to capture with UIImagePickerController if you do not need to alter it live. Once the video is captured and you have altered the audio track somehow, write it again using AVFoundation's AVMutableComposition and an audio mix.
What I'm doing :
I need to play audio and video files that are not supported by Apple on iPhone/iPad for example mkv/mka files which my contain several audio channels.
I'm using libffmpeg to find audio and video streams in media file.
Video is being decoded with avcodec_decode_video2 and audio with avcodec_decode_audio3
the return values are following for each function are following
avcodec_decode_video2 - returns AVFrame structure which encapsulates information about the video video frame from the pakcage, specifically is has data field which is a pointer to the picture/channel planes.
avcodec_decode_audio3 - returns samples of type int16_t * which I guess is the raw audio data
So basically I've done all this and successfully decoding the media content.
What I have to do :
I've to play the audio and video accordingly using Apples services. The playback I need to perform should support mixing of audio channels while playing video, i.e. let say mkv file contains two audio channel and a video channel. So I would like to know which service will be the appropriate choice for me ? My research showed that AudioQueue service might be useful audio playback, and probably AVFoundation for video.
Please help to find the right technology for my case i.e. video playeback + audio playback with possible audio channel mixing.
You are on the right path. If you are only playing audio (not recording at all) then I would use AudioQueues. It will do the mixing for you. If you are recording then you should use AudioUnits. Take a look at the MixerHost example project from Apple. For video I recommend using OpenGL. Assuming the image buffer is in YUV420 then you can render this with a simple two pass shader setup. I do believe there is an Apple example project showing how to do this. In any case you could render any pixel format using OpenGL and a shader to convert the pixel format to RGBA. Hope this help.
I know that I can access raw video images from the iPhone's camera with AVCaptureVideoDataOutput. I also know that I can record video to a file with AVCaptureMovieFileOutput. But how can I first access the raw video images, manipulate them and then write the manipulated ones into the video file? I've already seen apps in the app store, which do this, so it must be possible.
Ok, I now know, that it's done with AVAssetWriter.
Is it possible to play audio and video file at a same time? I want to play different audio file and video file at a same time and also want control for both, so is it possible?
Sorry, not that I know of. The movie view automatically stops all audio files and takes up the whole screen, so you are forced to listen to the audio for the video.
If the audio is part of the video file, yes.
If it's an MP3 file or some other external type how are you planning on playing it? The phone might allow this to happen depending on what you're up too.
You might be in luck soon though...
Another helpful link is here.
i am playing the video and in the background i have to play the audio file and if i do this audio is not playing its sound as it just play video is it a extension problem i am using the .mp3 for the audio and .mp4 for the video .
how can we do this we have to play simultanisouly .both the file
balraj verma
Have a look at this:
http://developer.apple.com/iphone/library/documentation/MusicAudio/Conceptual/CoreAudioOverview/CoreAudioEssentials/CoreAudioEssentials.html#//apple_ref/doc/uid/TP40003577-CH10-SW67
"To play multiple sounds simultaneously, create one playback audio queue object for each sound. For each audio queue, schedule the first buffer of audio to start at the same time using the AudioQueueEnqueueBufferWithParameters function.
Audio format is critical when you play sounds simultaneously on iPhone or iPod touch. This is because playback of certain compressed formats in iPhone OS employs an efficient hardware codec. Only a single instance of one of the following formats can play on the device at a time:
AAC
ALAC (Apple Lossless)
MP3"