I'm trying to stream a CMSampleBuffer video / audio combo using WebRTC on iOS, but I'm running into trouble trying to capture audio. Video works just fine:
guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
print("couldn't get image from buffer :~(")
return
}
let rtcPixelBuffer = RTCCVPixelBuffer(pixelBuffer: pixelBuffer)
let rtcVideoFrame = RTCVideoFrame(buffer: rtcPixelBuffer, rotation: ._0, timeStampNs: timeStampNs)
videoSource.capturer(videoCapturer, didCapture: rtcVideoFrame)
When it comes to audio, I can't see any method on the RTCAudioSource class in order to capture audio, any help would be appreciated!
I found a fork of the WebRTC codebase which solves this issue by adding a way for audio samples to be captured by an RTCAudioDeviceModule:
https://github.com/pixiv/webrtc/blob/87.0.4280.142-pixiv0/README.pixiv.en.md
Showing preview in 1080 x 1440; getting photo with max resolution (3024 x 4032) and quality on iPhone 8 Plus with code:
capturePhotoOutput?.capturePhoto(with: configurePhotoSettings(), delegate: self)
with photo settings:
private func configurePhotoSettings() -> AVCapturePhotoSettings {
let photoSettings = AVCapturePhotoSettings()
photoSettings.isHighResolutionPhotoEnabled = true
photoSettings.isAutoStillImageStabilizationEnabled = (capturePhotoOutput?.isStillImageStabilizationSupported)!
photoSettings.isAutoDualCameraFusionEnabled = (capturePhotoOutput?.isDualCameraFusionSupported)!
return photoSettings
}
Doing this one by one (like sequential shooting mode) and preview freezes each time for a short time even if I do nothing in didFinishProcessingPhoto.
Looking for solution to make capturing smooth, maybe in background thread, but currently I'm stuck..
The reason of preview hangs is feature called optical stabilization.
You just need to turn it off for smooth preview while capturing photo:
photoSettings.isAutoStillImageStabilizationEnabled = false
I am working on a function in my app to write images from my sample buffer to an AVAssetWriter. Curiously, this works fine on a 10.5" iPad Pro, but causes a crash on a 7.9" iPad Mini 2. I can't fathom how the same code could be problematic on two different devices. But here's my code;
func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
// Setup the pixel buffer image
let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
// Setup the format description
let formatDescription = CMSampleBufferGetFormatDescription(sampleBuffer)!
// Setup the current video dimensions
self.currentVideoDimensions = CMVideoFormatDescriptionGetDimensions(formatDescription)
// Setup the current sample time
self.currentSampleTime = CMSampleBufferGetOutputPresentationTimeStamp(sampleBuffer)
// Handle record
if self.isCapturing {
// Setup auto release pool
autoreleasepool {
// Setup the output image
let outputImage = CIImage(cvPixelBuffer: pixelBuffer)
// Ensure the video writer is ready for more data
if self.videoWriter?.assetWriterPixelBufferInput?.assetWriterInput.isReadyForMoreMediaData == true {
// Setup the new pixel buffer (THIS IS WHERE THE ERROR OCCURS)
var newPixelBuffer: CVPixelBuffer? = nil
// Setup the pixel buffer pool
CVPixelBufferPoolCreatePixelBuffer(nil, (self.videoWriter?.assetWriterPixelBufferInput!.pixelBufferPool!)!, &newPixelBuffer)
// Render the image to context
self.context.render(outputImage, to: newPixelBuffer!, bounds: outputImage.extent, colorSpace: nil)
// Setup a success case
let success = self.videoWriter?.assetWriterPixelBufferInput?.append(newPixelBuffer!, withPresentationTime: self.currentSampleTime!)
// Ensure the success case exists
guard let mySuccess = success else { return }
// If unsuccessful, log
if !mySuccess {
print("Error with the sample buffer. Check for dropped frames.")
}
}
}
}
}
I receive an error that newPixelBuffer is nil, but again, only on a 7.9" iPad. The iPad Pro functions without any errors. Any thoughts? Thanks!
I eventually resolved this issue by tracing the problem back to my chosen codec in my Asset Writer's video output settings. I had my codec set to:
let codec: AVVideoCodecType = AVVideoCodecType.hevc
In doing some research, I found this article, which indicates that only certain devices can capture media in HEVC. As my first device was a 10.5" iPad Pro, it captured media with no problem. My second device was an iPad Mini, which resulted in the original problem occurring each time I tried to capture.
I have since changed my codec choice to:
let codec: AVVideoCodecType = AVVideoCodecType.h264, and the issue has now disappeared.
Can anybody please explain to me why I am getting an error in this piece of code
My code never gets to the print statement that says, "Video Preview Layer added as sublayer". I am not sure why this is at all. The video preview layer is obviously created just before hand and then sent to be the sublayer of the camera view. My application is a paged based application. This is my second view that I have. My root view controller is blank for now, I am just trying to make sure the transition to my camera is seamless. Everything works when the camera is the 1st page in my application, or only one view controller. But for some reason now, it is telling me there is an unwrapped nil
/* Start The Capture Session */
func startSession() {
println("Now starting the session")
println("About to add session inputs...")
var error: NSError? = nil
let videoCapture = AVCaptureDeviceInput(device: self.cameraCaptureDevice, error: &error)
if error != nil {
println("Error, failed to add camera Capture Device: \(error?.description)")
}
// add video input
if self.session.canAddInput(videoCapture) {
self.session.addInput(videoCapture)
}
println("Start configuring the capture")
// config capture session
if !session.running {
// set JPEG output
self.stillImageOutput = AVCaptureStillImageOutput()
let outputSettings = [ AVVideoCodecKey : AVVideoCodecJPEG ]
self.stillImageOutput!.outputSettings = outputSettings
println("Successfully configured stillImageOutput")
// add output to session
println("Adding still image output to capture session")
if self.session.canAddOutput(stillImageOutput) {
self.session.addOutput(stillImageOutput)
}
println("Successfully added still image output")
println("Displaying camera in UI")
// display camera in UI
videoPreviewLayer = AVCaptureVideoPreviewLayer(session: session)
println("Video Preview Layer set")
cameraView.layer.addSublayer(videoPreviewLayer)
println("Video Preview Layer Added as sublayer")
videoPreviewLayer!.frame = cameraView.layer.frame
println("Video Preview frame set")
videoPreviewLayer!.videoGravity = AVLayerVideoGravityResizeAspectFill
println("Camera successully can display")
// start camera
self.session.startRunning()
println("Capture Session initiated")
}
}
The problem is that you are running this code at a time when cameraView is nil. You need to ask yourself why that is. If cameraView is an #IBOutlet, then this could happen, for example, if you call startSession from outside this view controller, at a time when the view controller is being created but has not yet called its own viewDidLoad (outlet connections are not connected until viewDidLoad has been called).
I'm accessing the camera in iOS and using session presets as so:
captureSession.sessionPreset = AVCaptureSessionPresetMedium;
Pretty standard stuff. However, I'd like to know ahead of time the resolution of the video I'll be getting due to this preset (especially because depending on the device it'll be different). I know there are tables online you can look this up (such as here: http://cmgresearch.blogspot.com/2010/10/augmented-reality-on-iphone-with-ios40.html ). But I'd like to be able to get this programmatically so that I'm not just relying on magic numbers.
So, something like this (theoretically):
[captureSession resolutionForPreset:AVCaptureSessionPresetMedium];
which might return a CGSize of { width: 360, height: 480}. I have not been able to find any such API, so far I've had to resort to waiting to get my first captured image and querying it then (which for other reasons in my program flow is not good).
I am no AVFoundation pro, but I think the way to go is:
captureSession.sessionPreset = AVCaptureSessionPresetMedium;
AVCaptureInput *input = [captureSession.inputs objectAtIndex:0]; // maybe search the input in array
AVCaptureInputPort *port = [input.ports objectAtIndex:0];
CMFormatDescriptionRef formatDescription = port.formatDescription;
CMVideoDimensions dimensions = CMVideoFormatDescriptionGetDimensions(formatDescription);
I'm not sure about the last step and I didn't try it myself. Just found that in the documentation and think it should work.
Searching for CMVideoDimensions in Xcode you'll find the RosyWriter example project. Have a look at that code (I don't have time to do that now).
You can programmatically get the resolution from activeFormat before capture begins, though not before adding inputs and outputs: https://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVCaptureDevice_Class/index.html#//apple_ref/occ/instp/AVCaptureDevice/activeFormat
private func getCaptureResolution() -> CGSize {
// Define default resolution
var resolution = CGSize(width: 0, height: 0)
// Get cur video device
let curVideoDevice = useBackCamera ? backCameraDevice : frontCameraDevice
// Set if video portrait orientation
let portraitOrientation = orientation == .Portrait || orientation == .PortraitUpsideDown
// Get video dimensions
if let formatDescription = curVideoDevice?.activeFormat.formatDescription {
let dimensions = CMVideoFormatDescriptionGetDimensions(formatDescription)
resolution = CGSize(width: CGFloat(dimensions.width), height: CGFloat(dimensions.height))
if (portraitOrientation) {
resolution = CGSize(width: resolution.height, height: resolution.width)
}
}
// Return resolution
return resolution
}
FYI, I attach here an official reply from Apple.
This is a follow-up to Bug ID# 13201137.
Engineering has determined that this issue behaves as intended based on the following information:
There are several problems with the included code:
1) The AVCaptureSession has no inputs.
2) The AVCaptureSession has no outputs.
Without at least one input (added to the session using [AVCaptureSession addInput:]) and a compatible output (added using [AVCaptureSession addOutput:]), there will be no active connections, therefore, the session won't actually run in the input device. It doesn't need to -- there are no outputs to which to deliver any camera data.
3) The JAViewController class assumes that the video port's -formatDescription property will be non nil as soon as [AVCaptureSession startRunning] returns.
There is no guarantee that the format description will be updated with the new camera format as soon as startRunning returns. -startRunning starts up the camera and returns when it is completely up and running, but doesn't wait for video frames to be actively flowing through the capture pipeline, which is when the format description would be updated.
You're just querying too fast. If you waited a few milliseconds more, it would be there. But the right way to do this is to listen for the AVCaptureInputPortFormatDescriptionDidChangeNotification.
4) Your JAViewController class creates a PVCameraInfo object in retrieveCameraInfo: and asks it a question, then lets it fall out of scope, where it is released and dealloc'ed.
Therefore, the session doesn't have long enough to run to satisfy your dimensions request. You stop the camera too quickly.
We consider this issue closed. If you have any questions or concern regarding this issue, please update your report directly (http://bugreport.apple.com).
Thank you for taking the time to notify us of this issue.
Best Regards,
Developer Bug Reporting Team
Apple Worldwide Developer Relations
According to Apple, there's no API for that. It stinks, I've had the same problem.
May be you can provide a list of all posible preset resolutions for every iPhone model and check which device model the app is running on? - using something like this...
[[UIDevice currentDevice] platformType] // ex: UIDevice4GiPhone
[[UIDevice currentDevice] platformString] // ex: #"iPhone 4G"
However, you have to update the list for each newer device model. Hope this helps :)
if preset is .photo, the return size is for still photo size, not preview video size
if preset is not .photo, the return size is for video size, not for captured photo size.
if self.session.sessionPreset != .photo {
// return video size, not captured photo size
let format = videoDevice.activeFormat
let formatDescription = format.formatDescription
let dimensions = CMVideoFormatDescriptionGetDimensions(formatDescription)
} else {
// other way to get video size
}
Answer of #Christian Beer is a good way for specified preset.
My way is a good for active preset.
The best way to do what you want (get a known video or image format) is to set the format of the capture device.
First find the capture device you want to use:
if #available(iOS 10.0, *) {
captureDevice = defaultCamera()
} else {
let devices = AVCaptureDevice.devices()
// Loop through all the capture devices on this phone
for device in devices {
// Make sure this particular device supports video
if ((device as AnyObject).hasMediaType(AVMediaType.video)) {
// Finally check the position and confirm we've got the back camera
if((device as AnyObject).position == AVCaptureDevice.Position.back) {
captureDevice = device as AVCaptureDevice
}
}
}
}
self.autoLevelWindowCenter = ALCWindow.frame
if captureDevice != nil && currentUser != nil {
beginSession()
}
}
func defaultCamera() -> AVCaptureDevice? {
if #available(iOS 10.0, *) { // only use the wide angle camera never dual camera
if let device = AVCaptureDevice.default(AVCaptureDevice.DeviceType.builtInWideAngleCamera,
for: AVMediaType.video,
position: .back) {
return device
} else {
return nil
}
} else {
return nil
}
}
Then find the formats that that device can use:
let options = captureDevice!.formats
var supportable = options.first as! AVCaptureDevice.Format
for format in options {
let testFormat = format
let description = testFormat.description
if (description.contains("60 fps") && description.contains("1280x 720")){
supportable = testFormat
}
}
You can do more complex parsing of the formats, but you might not care.
Then just set the device to that format:
do {
try captureDevice?.lockForConfiguration()
captureDevice!.activeFormat = supportable
// setup other capture device stuff like autofocus, frame rate, ISO, shutter speed, etc.
try captureSession.addInput(AVCaptureDeviceInput(device: captureDevice!))
// add the device to an active CaptureSession
}
You may want to look at the AVFoundation docs and tutorial on AVCaptureSession as there are lots of things you can do with the output as well. For example, you can convert the result to .mp4 using AVAssetExportSession so that you can post it on YouTube, etc.
Hope this helps
Apple is using 4:3 ratio for the iPhone camera.
You can you this ratio to get the frame size of the captured video by fixing either the width or height constraint of the AVCaptureVideoPreviewLayer and set the aspect ratio constraint to 4:3.
In the left image, the width was fixed to 300px and the height was retrieved by setting the 4:3 ratio, and it was 400px.
In the right image, the height was fixed to 300px and width was retrieved by setting the 3:4 ratio, and it was 225px.