How to fetch h.264 bytes from iPhone Camera? [duplicate] - iphone

Question

This question already has answers here:
How can we get H.264 encoded video stream from iPhone Camera?
(3 answers)
Closed 9 years ago.
I need to publish live video stream from iPhone Camera to RTMP Server (Wowza server). The video stream must be in h.264 format. I know AVFoundation stores video to a file in h.264 compression but I don;t need to store the video to a file. I just want to capture and send it to the server. I am using following delegate method :
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
if (connection == videoConnection) {
//I want something like this
NSData* h264VideoData=[self h264Data:sampleBuffer];
}
}
I don't need to send audio to the server, I just want to send video.

Answer 1

Update for 2017:
You can do streaming Video and Audio now by using the VideoToolbox API.
Read the documentation here: VTCompressionSession
Original answer (from 2013):
That is currently not possible, you'll have to write to a file or compress the video stream with a software-encoder (you won't get HD and very bad battery times though). All possibilities to get a hand on the hardware-encoder have to write to the disk. I think this is because of memory shortage on the devices.
Methods to get hardware accelerated h264 compression:
AVAssetWriter
AVCaptureMovieFileOutput
As you can see both write to a file, writing to a pipe does not work as the encoder updates header information after a frame or GOP has been fully written. So you better don't touch the file while the encoder writes to it as it does randomly rewrite header information. Without this header information the video file will not be playable (it updates the size field, so the first header written says the file is 0 bytes).
You can, however, record 5 seconds and then switch the output-file, transmit the now "old" 5 seconds snippet and delete it afterwards. You'll have to demux the *.mov or *.mp4 container though to get to the h264 video data to send.
If you need audio: if you switch the file you'll loose some audio samples, so you'll have to roll your own buffer management for that (or just record audio separately).