/*

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

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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