/*

File: LiveVideo.mm

Abstract: LiveVideo class implementation. This is a simple wrapper on top of the Sequence Grabber that uses
          the SGDataProc to decompress frames using an ICMDecompressionSession to an OpenGL VisualContext.

Version: 1.0

© Copyright 2005 Apple Computer, Inc. All rights reserved.

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Revision History:
	<1>	08/08/2005  initial release

*/

#import "LiveVideo.h"
#import <QuickTime/QuickTime.h>
#import <QuartzCore/QuartzCore.h>

@implementation LiveVideo

// sequence grabber data proc callback set by calling SGSetDataProc
static pascal OSErr GrabberDataProc(SGChannel c, Ptr p, long len, long *offset, long chRefCon, TimeValue time, short writeType, long refCon)
{
	return [(LiveVideo*)refCon handleData:p length:len time:time];
}

static void TrackDecompression(void *decompressionTrackingRefCon,
                               OSStatus result,
                               ICMDecompressionTrackingFlags decompressionTrackingFlags,
                               CVPixelBufferRef pixelBuffer,
                               TimeValue64 displayTime,
                               TimeValue64 displayDuration,
                               ICMValidTimeFlags validTimeFlags,
                               void *sourceFrameRefCon, void *reserved)
{
}

// timer method for tasking the sequence grabber
-(void)taskGrabber
{
	static const double idleInterval = 1.0 / 60.0;

	SGIdle(_grabber);
	
	if (_timer == nil)
		_timer = [[NSTimer scheduledTimerWithTimeInterval:idleInterval target:self selector:@selector(taskGrabber) userInfo:self repeats:YES] retain];
}

// initialize the sequence grabber object
-(id)initWithVisualContext:(QTVisualContextRef)visualContext
{
	OSStatus err = noErr;
	Rect bounds = {0, 0, 480, 640};

	[super init];
    
    // retain the visual context for our own use
	_visualContext = QTVisualContextRetain(visualContext);
	_size = NSMakeSize(bounds.right, bounds.bottom);
	
    // standard SG initialization
	_grabber = OpenDefaultComponent(SeqGrabComponentType, 0);
	require_action(_grabber != NULL, bail, err = memFullErr);
	
	err = SGInitialize(_grabber);
	require_noerr(err, bail);

	err = SGSetDataRef(_grabber, 0, 0, seqGrabDontMakeMovie);
	require_noerr(err, bail);
	
	err = QTNewGWorld(&_offscreen, 32, &bounds, nil, nil, 0);
	LockPixels(GetGWorldPixMap(_offscreen));
	require_noerr(err, bail);
	
	err = SGNewChannel(_grabber, VideoMediaType, &_channel);
	require_noerr(err, bail);

	err = SGSetGWorld(_channel, _offscreen, GetGWorldDevice(_offscreen));
	require_noerr(err, bail);

	err = SGSetChannelBounds(_channel, &bounds);
	require_noerr(err, bail);

	err = SGSetChannelUsage(_channel, seqGrabRecord);
	require_noerr(err, bail);

	err = SGSetDataProc(_grabber, &GrabberDataProc, (long)self);
	require_noerr(err, bail);
	
	err = SGStartRecord(_grabber);
	require_noerr(err, bail);
	
	[self taskGrabber];
	
bail:
	if (err != noErr)
	{
		[self release];
		return nil;
	}
	
	return self;
}

// deaccolate the object
-(void)dealloc
{
	if (_timer != nil)
	{
		[_timer invalidate];
		[_timer release];
	}

	if (_grabber != NULL)
		SGStop(_grabber);
	
	ICMDecompressionSessionRelease(_session);
	
	if (_imageDescription != nil)
		DisposeHandle( (Handle) _imageDescription);
	
	if (_channel != nil)
		SGDisposeChannel(_grabber, _channel);
	
	if (_grabber != nil)
		CloseComponent(_grabber);
		
	if (_offscreen != nil)
		DisposeGWorld(_offscreen);
	
    // we make sure to release the visual context
	QTVisualContextRelease(_visualContext);
    
	[super dealloc];
}

// this method is called evertime we have data from the SG data proc and is where
// the work of decompressing the frame is done
-(OSErr)handleData:(void*)data length:(long)length time:(TimeValue)timeValue
{
	OSStatus err = noErr;
	ICMFrameTimeRecord now = {0};

	// Create our decompression session the first time through
	if (_imageDescription == nil)
	{
        // create a tracking callback record, this is mandatory
        // the TrackingCallback is used to track information about queued frames,
        // pixel buffers, errors, status and so on about the decompressed frames
		ICMDecompressionTrackingCallbackRecord trackingCallback = {&TrackDecompression, self};

		err = SGGetChannelTimeScale(_channel, &_timeScale);
		require_noerr(err, bail);
		
		_imageDescription = (ImageDescriptionHandle)NewHandle(0);
		err = SGGetChannelSampleDescription(_channel, (Handle) _imageDescription);
		require_noerr(err, bail);
		
        // create a decompression session for our visual context, Frames will be output to a visual context
        // If desired, the trackingCallback may be used to add additional data to pixel buffers before they are sent to the visual context
        // or to keep track of the status of the decompression
		err = ICMDecompressionSessionCreateForVisualContext(NULL, _imageDescription, NULL, _visualContext, &trackingCallback, &_session);
		require_noerr(err, bail);
	}
	
	// Fill in the frame time
	now.recordSize = sizeof(ICMFrameTimeRecord);
	*(TimeValue64*)&now.value = timeValue;
	now.scale = _timeScale;
	now.rate = fixed1;
	now.decodeTime = timeValue;
	now.frameNumber = _frameNumber++;
	now.flags = icmFrameTimeIsNonScheduledDisplayTime;

	// Enqueue frame
	err = ICMDecompressionSessionDecodeFrame(_session, (const UInt8*)data, length, NULL, &now, self);
	require_noerr(err, bail);
	
	// Force frame out
	err = ICMDecompressionSessionSetNonScheduledDisplayTime(_session, *(long long int*)&now.value, _timeScale, 0);
	require_noerr(err, bail);
	
bail:
	return err;
}

-(NSSize)size
{
	return _size;
}

@end