ffmpeg视频流采集

ffmpeg视频流采集

// AForge FFMPEG Library
// AForge.NET framework
// http://www.aforgenet.com/framework/
//
// Copyright ?AForge.NET, 2009-2011
// contacts@aforgenet.com
//

#include "StdAfx.h"
#include "VideoFileSource.h"
#include "VideoFileReader.h"

namespace AForge { namespace Video { namespace FFMPEG
{

VideoFileSource::VideoFileSource( String^ fileName )
{
m_fileName = fileName;
m_workerThread = nullptr;
m_needToStop = nullptr;

m_frameIntervalFromSource = true;
m_frameInterval = 0;
}

void VideoFileSource::Start( )
{
if ( !IsRunning )
{
        // check source
if ( String::IsNullOrEmpty( m_fileName ) )
{
            throw gcnew ArgumentException( "Video file name is not specified." );
}

m_framesReceived = 0;
        m_bytesReceived = 0;

// create events
m_needToStop = gcnew ManualResetEvent( false );

// create and start new thread
m_workerThread = gcnew Thread( gcnew ThreadStart( this, &VideoFileSource::WorkerThreadHandler ) );
m_workerThread->Name = m_fileName; // just for debugging
m_workerThread->Start( );
}
}

void VideoFileSource::SignalToStop( )
{
if ( m_workerThread != nullptr )
{
// signal to stop
m_needToStop->Set( );
}
}

void VideoFileSource::WaitForStop( )
{
if ( m_workerThread != nullptr )
{
// wait for thread stop
m_workerThread->Join( );

Free( );
}
}

void VideoFileSource::Stop( )
{
if ( IsRunning )
{
m_workerThread->Abort( );
WaitForStop( );
}
}

void VideoFileSource::Free( )
{
m_workerThread = nullptr;

// release events
m_needToStop->Close( );
m_needToStop = nullptr;
}

void VideoFileSource::WorkerThreadHandler( )
{
ReasonToFinishPlaying reasonToStop = ReasonToFinishPlaying::StoppedByUser;
VideoFileReader^ videoReader = gcnew VideoFileReader( );

try
{
videoReader->Open( m_fileName );

        // frame interval
        int interval = ( m_frameIntervalFromSource ) ?
(int) ( 1000 / ( ( videoReader->FrameRate == 0 ) ? 25 : videoReader->FrameRate ) ) :
m_frameInterval;

        while ( !m_needToStop->WaitOne( 0, false ) )
{
// start time
DateTime start = DateTime::Now;

// get next video frame
Bitmap^ bitmap = videoReader->ReadVideoFrame( );

if ( bitmap == nullptr )
{
reasonToStop = ReasonToFinishPlaying::EndOfStreamReached;
                break;
}

m_framesReceived ;
            m_bytesReceived = bitmap->Width * bitmap->Height *
                ( Bitmap::GetPixelFormatSize( bitmap->PixelFormat ) >> 3 );

// notify clients about the new video frame
NewFrame( this, gcnew NewFrameEventArgs( bitmap ) );

// dispose the frame since we no longer need it
delete bitmap;

            // wait for a while ?
            if ( interval > 0 )
            {
                // get frame extract duration
TimeSpan^ span = DateTime::Now.Subtract( start );

                // miliseconds to sleep
                int msec = interval - (int) span->TotalMilliseconds;

                if ( ( msec > 0 ) && ( m_needToStop->WaitOne( msec, false ) == true ) )
break;
            }
}
}
catch ( Exception^ exception )
{
        VideoSourceError( this, gcnew VideoSourceErrorEventArgs( exception->Message ) );
}

videoReader->Close( );
PlayingFinished( this, reasonToStop );
}

} } }