itgmania212121/stepmania/src/arch/MovieTexture/MovieTexture_FFMpeg.cpp

#include "global.h"
#include "MovieTexture_FFMpeg.h"

#include "RageLog.h"
#include "RageTextureManager.h"
#include "RageUtil.h"
#include "RageTimer.h"
#include "RageFile.h"
#include "RageSurface.h"
#include "PrefsManager.h"

#include <cerrno>

#if defined(WIN32) && !defined(XBOX)
#include <windows.h>
#endif

namespace avcodec
{
#if defined(WIN32)
#include "ffmpeg/include/ffmpeg/avformat.h"
#else
#include <ffmpeg/avformat.h>
#endif
};

#if defined(_MSC_VER) && !defined(XBOX)
	#pragma comment(lib, "ffmpeg/lib/avcodec.lib")
	#pragma comment(lib, "ffmpeg/lib/avformat.lib")
#endif

struct AVPixelFormat_t
{
	int bpp;
	int masks[4];
	avcodec::PixelFormat pf;
	bool HighColor;
	bool ByteSwapOnLittleEndian;
} AVPixelFormats[] = {
	{ 
		/* This format is really ARGB, and is affected by endianness, unlike PIX_FMT_RGB24
		 * and PIX_FMT_BGR24. */
		32,
		{ 0x00FF0000,
		  0x0000FF00,
		  0x000000FF,
		  0xFF000000 },
		avcodec::PIX_FMT_RGBA32,
		true,
		false
	},
	{ 
		24,
		{ 0xFF0000,
		  0x00FF00,
		  0x0000FF,
		  0x000000 },
		avcodec::PIX_FMT_RGB24,
		true,
		true
	},
	{ 
		24,
		{ 0x0000FF,
		  0x00FF00,
		  0xFF0000,
		  0x000000 },
		avcodec::PIX_FMT_BGR24,
		true,
		true
	},
	{
		16,
		{ 0x7C00,
		  0x03E0,
		  0x001F,
		  0x8000 },
		avcodec::PIX_FMT_RGB555,
		false,
		false
	},
	{ 0, { 0,0,0,0 }, avcodec::PIX_FMT_NB, true, false }
};

static void FixLilEndian()
{
#if defined(ENDIAN_LITTLE)
	static bool Initialized = false;
	if( Initialized )
		return; 
	Initialized = true;

	for( int i = 0; i < AVPixelFormats[i].bpp; ++i )
	{
		AVPixelFormat_t &pf = AVPixelFormats[i];

		if( !pf.ByteSwapOnLittleEndian )
			continue;

		for( int mask = 0; mask < 4; ++mask)
		{
			int m = pf.masks[mask];
			switch( pf.bpp )
			{
				case 24: m = Swap24(m); break;
				case 32: m = Swap32(m); break;
				default: ASSERT(0);
			}
			pf.masks[mask] = m;
		}
	}
#endif
}

static int FindCompatibleAVFormat( PixelFormat &pixfmt, bool HighColor )
{
	for( int i = 0; AVPixelFormats[i].bpp; ++i )
	{
		AVPixelFormat_t &fmt = AVPixelFormats[i];
		if( fmt.HighColor != HighColor )
			continue;

		pixfmt = DISPLAY->FindPixelFormat( fmt.bpp,
				fmt.masks[0],
				fmt.masks[1],
				fmt.masks[2],
				fmt.masks[3],
				true /* realtime */
				);

		if( pixfmt == PixelFormat_INVALID )
			continue;

		return i;
	}

	return -1;
}

class FFMpeg_Helper
{
public:
	FFMpeg_Helper();
	~FFMpeg_Helper();
	int GetFrame();
	void Init();

	CString Open( CString sFile );
	void Close();

	/* Get the timestamp, in seconds, when the current frame should be
	 * displayed.  The first frame will always be 0. */
	float GetTimestamp() const;

	/* Get the duration, in seconds, to display the current frame. */
	float GetFrameDuration() const;

	avcodec::AVStream *m_stream;
	avcodec::AVFrame frame;

private:
	float m_fPTS;
	avcodec::AVFormatContext *m_fctx;
	bool m_bGetNextTimestamp;
	float m_fCurrentTimestamp;
	float m_fLastFrameDelay;
	int m_iFrameNumber;

	avcodec::AVPacket pkt;
	int m_iCurrentPacketOffset;

	/* 0 = no EOF
	 * 1 = EOF from ReadPacket
	 * 2 = EOF from ReadPacket and DecodePacket */
	int m_iEOF;

	int ReadPacket();
	int DecodePacket();
	float m_fTimestampOffset;
};

FFMpeg_Helper::FFMpeg_Helper()
{
	m_fctx = NULL;
	m_stream = NULL;
	m_iCurrentPacketOffset = -1;
	Init();
}

FFMpeg_Helper::~FFMpeg_Helper()
{
	if( m_iCurrentPacketOffset != -1 )
	{
		avcodec::av_free_packet( &pkt );
		m_iCurrentPacketOffset = -1;
	}
}

void FFMpeg_Helper::Init()
{
	m_iEOF = 0;
	m_bGetNextTimestamp = true;
	m_fCurrentTimestamp = 0;
	m_fLastFrameDelay = 0;
	m_fPTS = -1;
	m_iFrameNumber = -1; /* decode one frame and you're on the 0th */
	m_fTimestampOffset = 0;

	if( m_iCurrentPacketOffset != -1 )
	{
		avcodec::av_free_packet( &pkt );
		m_iCurrentPacketOffset = -1;
	}
}

/* Read until we get a frame, EOF or error.  Return -1 on error, 0 on EOF, 1 if we have a frame. */
int FFMpeg_Helper::GetFrame()
{
	while( 1 )
	{
		int ret = DecodePacket();
		if( ret == 1 )
			break;
		if( ret == -1 )
			return -1;
		if( ret == 0 && m_iEOF > 0 )
			return 0; /* eof */

		ASSERT( ret == 0 );
		ret = ReadPacket();
		if( ret < 0 )
			return ret; /* error */
	}

	++m_iFrameNumber;

	if( m_iFrameNumber == 1 )
	{
		/* Some videos start with a timestamp other than 0.  I think this is used
		 * when audio starts before the video.  We don't want to honor that, since
		 * the DShow renderer doesn't and we don't want to break sync compatibility.
		 *
		 * Look at the second frame.  (If we have B-frames, the first frame will be an
		 * I-frame with the timestamp of the next P-frame, not its own timestamp, and we
		 * want to ignore that and look at the next B-frame.) */
		const float expect = m_fLastFrameDelay;
		const float actual = m_fCurrentTimestamp;
		if( actual - expect > 0 )
		{
			LOG->Trace("Expect %f, got %f -> %f", expect, actual, actual - expect );
			m_fTimestampOffset = actual - expect;
		}
	}

	return 1;
}

float FFMpeg_Helper::GetTimestamp() const
{
	/* The first frame always has a timestamp of 0. */
	if( m_iFrameNumber == 0 )
		return 0;

	return m_fCurrentTimestamp - m_fTimestampOffset;
}

float FFMpeg_Helper::GetFrameDuration() const
{
	return m_fLastFrameDelay;
}

/* Read a packet.  Return -1 on error, 0 on EOF, 1 on OK. */
int FFMpeg_Helper::ReadPacket()
{
	if( m_iEOF > 0 )
		return 0;

	while( 1 )
	{
		CHECKPOINT;
		if( m_iCurrentPacketOffset != -1 )
		{
			m_iCurrentPacketOffset = -1;
			avcodec::av_free_packet( &pkt );
		}

		int ret = avcodec::av_read_frame( m_fctx, &pkt );
		/* XXX: why is avformat returning AVERROR_NOMEM on EOF? */
		if( ret < 0 )
		{
			/* EOF. */
			m_iEOF = 1;
			pkt.size = 0;
			
			return 0;
		}

		if( pkt.stream_index == m_stream->index )
		{
			m_iCurrentPacketOffset = 0;
			return 1;
		}

		/* It's not for the video stream; ignore it. */
		avcodec::av_free_packet( &pkt );
	}
}


/* Decode data from the current packet.  Return -1 on error, 0 if the packet is finished,
 * and 1 if we have a frame (we may have more data in the packet). */
int FFMpeg_Helper::DecodePacket()
{
	if( m_iEOF == 0 && m_iCurrentPacketOffset == -1 )
		return 0; /* no packet */

	while( m_iEOF == 1 || (m_iEOF == 0 && m_iCurrentPacketOffset < pkt.size) )
	{
		if( m_bGetNextTimestamp )
		{
			if (pkt.dts != int64_t(AV_NOPTS_VALUE))
				m_fPTS = (float)pkt.dts / AV_TIME_BASE;
			else
				m_fPTS = -1;
			m_bGetNextTimestamp = false;
		}

		/* If we have no data on the first frame, just return EOF; passing an empty packet
		 * to avcodec_decode_video in this case is crashing it.  However, passing an empty
		 * packet is normal with B-frames, to flush.  This may be unnecessary in newer
		 * versions of avcodec, but I'm waiting until a new stable release to upgrade. */
		if( pkt.size == 0 && m_iFrameNumber == -1 )
			return 0; /* eof */

		int got_frame;
		CHECKPOINT;
		/* Hack: we need to send size = 0 to flush frames at the end, but we have
		 * to give it a buffer to read from since it tries to read anyway. */
		static uint8_t dummy[FF_INPUT_BUFFER_PADDING_SIZE] = { 0 };
		int len = avcodec::avcodec_decode_video(
				&m_stream->codec, 
				&frame, &got_frame,
				pkt.size? pkt.data:dummy, pkt.size );
		CHECKPOINT;

		if( len < 0 )
		{
			LOG->Warn("avcodec_decode_video: %i", len);
			return -1; // XXX
		}

		m_iCurrentPacketOffset += len;

		if( !got_frame )
		{
			if( m_iEOF == 1 )
				m_iEOF = 2;
			continue;
		}

		m_bGetNextTimestamp = true;

		if( m_fPTS != -1 )
		{
			m_fCurrentTimestamp = m_fPTS;
		}
		else
		{
			/* If the timestamp is zero, this frame is to be played at the
			 * time of the last frame plus the length of the last frame. */
			m_fCurrentTimestamp += m_fLastFrameDelay;
		}

		/* Length of this frame: */
		m_fLastFrameDelay = (float)m_stream->codec.frame_rate_base / m_stream->codec.frame_rate;
		m_fLastFrameDelay += frame.repeat_pict * (m_fLastFrameDelay * 0.5f);

		return 1;
	}

	return 0; /* packet done */
}

void MovieTexture_FFMpeg::ConvertFrame()
{
	ASSERT_M( m_ImageWaiting == FRAME_DECODED, ssprintf("%i", m_ImageWaiting ) );

	avcodec::AVPicture pict;
	pict.data[0] = (unsigned char *) m_pSurface->pixels;
	pict.linesize[0] = m_pSurface->pitch;

	avcodec::img_convert( &pict, AVPixelFormats[m_AVTexfmt].pf,
			(avcodec::AVPicture *) &m_pDecoder->frame, m_pDecoder->m_stream->codec.pix_fmt, 
			m_pDecoder->m_stream->codec.width, m_pDecoder->m_stream->codec.height );

	m_ImageWaiting = FRAME_WAITING;
}

static avcodec::AVStream *FindVideoStream( avcodec::AVFormatContext *m_fctx )
{
    for( int stream = 0; stream < m_fctx->nb_streams; ++stream )
	{
		avcodec::AVStream *enc = m_fctx->streams[stream];
        if( enc->codec.codec_type == avcodec::CODEC_TYPE_VIDEO )
			return enc;
	}
	return NULL;
}

MovieTexture_FFMpeg::MovieTexture_FFMpeg( RageTextureID ID ):
	RageMovieTexture( ID ),
	m_BufferFinished( "BufferFinished", 0 )
{
	LOG->Trace( "MovieTexture_FFMpeg::MovieTexture_FFMpeg(%s)", ID.filename.c_str() );

	FixLilEndian();

	m_pDecoder = new FFMpeg_Helper;

	m_uTexHandle = 0;
	m_bLoop = true;
    m_State = DECODER_QUIT; /* it's quit until we call StartThread */
	m_pSurface = NULL;
	m_ImageWaiting = FRAME_NONE;
	m_fRate = 1;
	m_bWantRewind = false;
	m_fClock = 0;
	m_bFrameSkipMode = false;
	m_bThreaded = PREFSMAN->m_bThreadedMovieDecode.Get();
}

CString MovieTexture_FFMpeg::Init()
{
	CString sError = CreateDecoder();
	if( sError != "" )
		return sError;

	LOG->Trace( "Bitrate: %i", m_pDecoder->m_stream->codec.bit_rate );
	LOG->Trace( "Codec pixel format: %s", avcodec::avcodec_get_pix_fmt_name(m_pDecoder->m_stream->codec.pix_fmt) );

	/* Decode one frame, to guarantee that the texture is drawn when this function returns. */
	int ret = m_pDecoder->GetFrame();
	if( ret == -1 )
		return ssprintf( "%s: error getting first frame", GetID().filename.c_str() );
	if( ret == 0 )
	{
		/* There's nothing there. */
		return ssprintf( "%s: EOF getting first frame", GetID().filename.c_str() );
	}

	m_ImageWaiting = FRAME_DECODED;

	CreateTexture();
	LOG->Trace( "Resolution: %ix%i (%ix%i, %ix%i)",
			m_iSourceWidth, m_iSourceHeight,
			m_iImageWidth, m_iImageHeight, m_iTextureWidth, m_iTextureHeight );
	LOG->Trace( "Texture pixel format: %i", m_AVTexfmt );

	CreateFrameRects();

	ConvertFrame();
	UpdateFrame();

	CHECKPOINT;

	StartThread();

	return CString();
}

MovieTexture_FFMpeg::~MovieTexture_FFMpeg()
{
	StopThread();
	DestroyDecoder();
	DestroyTexture();

	delete m_pDecoder;
}


static CString averr_ssprintf( int err, const char *fmt, ... )
{
	ASSERT( err < 0 );

	va_list     va;
	va_start(va, fmt);
	CString s = vssprintf( fmt, va );
	va_end(va); 

	CString Error;
	switch( err )
	{
	case AVERROR_IO:			Error = "I/O error"; break;
	case AVERROR_NUMEXPECTED:	Error = "number syntax expected in filename"; break;
	case AVERROR_INVALIDDATA:	Error = "invalid data found"; break;
	case AVERROR_NOMEM:			Error = "not enough memory"; break;
	case AVERROR_NOFMT:			Error = "unknown format"; break;
	case AVERROR_UNKNOWN:		Error = "unknown error"; break;
	default: Error = ssprintf( "unknown error %i", err ); break;
	}

	return s + " (" + Error + ")";
}

int URLRageFile_open( avcodec::URLContext *h, const char *filename, int flags )
{
	if( strncmp( filename, "rage://", 7 ) )
	{
		LOG->Warn("URLRageFile_open: Unexpected path \"%s\"", filename );
	    return -EIO;
	}
	filename += 7;

	int mode = 0;
	switch( flags )
	{
	case URL_RDONLY: mode = RageFile::READ; break;
	case URL_WRONLY: mode = RageFile::WRITE | RageFile::STREAMED; break;
	case URL_RDWR: FAIL_M( "O_RDWR unsupported" );
	}

	RageFile *f = new RageFile;
	if( !f->Open(filename, mode) )
	{
		LOG->Trace("Error opening \"%s\": %s", filename, f->GetError().c_str() );
		delete f;
	    return -EIO;
	}

	h->is_streamed = false;
	h->priv_data = f;
	return 0;
}

int URLRageFile_read( avcodec::URLContext *h, unsigned char *buf, int size )
{
	RageFile *f = (RageFile *) h->priv_data;
	return f->Read( buf, size );
}

int URLRageFile_write( avcodec::URLContext *h, unsigned char *buf, int size )
{
	RageFile *f = (RageFile *) h->priv_data;
	return f->Write( buf, size );
}

avcodec::offset_t URLRageFile_seek( avcodec::URLContext *h, avcodec::offset_t pos, int whence )
{
	RageFile *f = (RageFile *) h->priv_data;
	return f->Seek( (int) pos, whence );
}

int URLRageFile_close( avcodec::URLContext *h )
{
	RageFile *f = (RageFile *) h->priv_data;
	delete f;
	return 0;
}

static avcodec::URLProtocol RageProtocol =
{
	"rage",
	URLRageFile_open,
	URLRageFile_read,
	URLRageFile_write,
	URLRageFile_seek,
	URLRageFile_close,
	NULL
};

CString FFMpeg_Helper::Open( CString sFile )
{
	static bool bDone = false;
	if( !bDone )
	{
		avcodec::av_register_all();
		avcodec::register_protocol( &RageProtocol );
		bDone = true;
	}

	int ret = avcodec::av_open_input_file( &m_fctx, "rage://" + sFile, NULL, 0, NULL );
	if( ret < 0 )
		return ssprintf( averr_ssprintf(ret, "AVCodec: Couldn't open \"%s\"", sFile.c_str()) );

	ret = avcodec::av_find_stream_info( m_fctx );
	if( ret < 0 )
		return ssprintf( averr_ssprintf(ret, "AVCodec (%s): Couldn't find codec parameters", sFile.c_str()) );

	avcodec::AVStream *stream = FindVideoStream( m_fctx );
	if ( stream == NULL )
		return ssprintf( "AVCodec (%s): Couldn't find any video streams", sFile.c_str() );

	if( stream->codec.codec_id == avcodec::CODEC_ID_NONE )
		return ssprintf( "AVCodec (%s): Unsupported codec %08x", sFile.c_str(), stream->codec.codec_tag );

	avcodec::AVCodec *codec = avcodec::avcodec_find_decoder( stream->codec.codec_id );
	if( codec == NULL )
		return ssprintf( "AVCodec (%s): Couldn't find decoder %i", sFile.c_str(), stream->codec.codec_id );

	LOG->Trace("Opening codec %s", codec->name );
	ret = avcodec::avcodec_open( &stream->codec, codec );
	if ( ret < 0 )
		return ssprintf( averr_ssprintf(ret, "AVCodec (%s): Couldn't open codec \"%s\"", sFile.c_str(), codec->name) );

	/* Don't set this until we successfully open stream->codec, so we don't try to close it
	 * on an exception unless it was really opened. */
	m_stream = stream;

	return CString();
}

void FFMpeg_Helper::Close()
{
	if( m_stream )
	{
		avcodec::avcodec_close( &m_stream->codec );
		m_stream = NULL;
	}

	if( m_fctx )
	{
		avcodec::av_close_input_file( m_fctx );
		m_fctx = NULL;
	}
}

CString MovieTexture_FFMpeg::CreateDecoder()
{
	return m_pDecoder->Open( GetID().filename );
}


/* Delete the decoder.  The decoding thread must be stopped. */
void MovieTexture_FFMpeg::DestroyDecoder()
{
	m_pDecoder->Close();
}

/* Delete the surface and texture.  The decoding thread must be stopped, and this
 * is normally done after destroying the decoder. */
void MovieTexture_FFMpeg::DestroyTexture()
{
	delete m_pSurface;
	m_pSurface = NULL;

	if( m_uTexHandle )
	{
		DISPLAY->DeleteTexture( m_uTexHandle );
		m_uTexHandle = 0;
	}
}


void MovieTexture_FFMpeg::CreateTexture()
{
    if( m_uTexHandle )
        return;

	CHECKPOINT;

	RageTextureID actualID = GetID();
	actualID.iAlphaBits = 0;

	/* Cap the max texture size to the hardware max. */
	actualID.iMaxSize = min( actualID.iMaxSize, DISPLAY->GetMaxTextureSize() );

	m_iSourceWidth  = m_pDecoder->m_stream->codec.width;
	m_iSourceHeight = m_pDecoder->m_stream->codec.height;

	/* image size cannot exceed max size */
	m_iImageWidth = min( m_iSourceWidth, actualID.iMaxSize );
	m_iImageHeight = min( m_iSourceHeight, actualID.iMaxSize );

	/* Texture dimensions need to be a power of two; jump to the next. */
	m_iTextureWidth = power_of_two( m_iImageWidth );
	m_iTextureHeight = power_of_two( m_iImageHeight );

	/* Bogus assignment to shut gcc up. */
    PixelFormat pixfmt = PixelFormat_RGBA8;
	bool bPreferHighColor = (TEXTUREMAN->GetPrefs().m_iMovieColorDepth == 32);
	m_AVTexfmt = FindCompatibleAVFormat( pixfmt, bPreferHighColor );

	if( m_AVTexfmt == -1 )
		m_AVTexfmt = FindCompatibleAVFormat( pixfmt, !bPreferHighColor );

	if( m_AVTexfmt == -1 )
	{
		/* No dice.  Use the first avcodec format of the preferred bit depth,
		 * and let the display system convert. */
		for( m_AVTexfmt = 0; AVPixelFormats[m_AVTexfmt].bpp; ++m_AVTexfmt )
			if( AVPixelFormats[m_AVTexfmt].HighColor == bPreferHighColor )
				break;
		ASSERT( AVPixelFormats[m_AVTexfmt].bpp );

		switch( TEXTUREMAN->GetPrefs().m_iMovieColorDepth )
		{
		default:
			ASSERT(0);
		case 16:
			if( DISPLAY->SupportsTextureFormat(PixelFormat_RGB5) )
				pixfmt = PixelFormat_RGB5;
			else
				pixfmt = PixelFormat_RGBA4; // everything supports RGBA4

			break;

		case 32:
			if( DISPLAY->SupportsTextureFormat(PixelFormat_RGB8) )
				pixfmt = PixelFormat_RGB8;
			else if( DISPLAY->SupportsTextureFormat(PixelFormat_RGBA8) )
				pixfmt = PixelFormat_RGBA8;
			else if( DISPLAY->SupportsTextureFormat(PixelFormat_RGB5) )
				pixfmt = PixelFormat_RGB5;
			else
				pixfmt = PixelFormat_RGBA4; // everything supports RGBA4
			break;
		}
	}
	
	if( m_pSurface == NULL )
	{
		const AVPixelFormat_t *pfd = &AVPixelFormats[m_AVTexfmt];

		LOG->Trace("format %i, %08x %08x %08x %08x",
			pfd->bpp, pfd->masks[0], pfd->masks[1], pfd->masks[2], pfd->masks[3]);

		m_pSurface = CreateSurface( m_iTextureWidth, m_iTextureHeight, pfd->bpp,
			pfd->masks[0], pfd->masks[1], pfd->masks[2], pfd->masks[3] );
	}

    m_uTexHandle = DISPLAY->CreateTexture( pixfmt, m_pSurface, false );
}

/* Handle decoding for a frame.  Return true if a frame was decoded, false if not
 * (due to pause, EOF, etc).  If true is returned, we'll be in FRAME_DECODED. */
bool MovieTexture_FFMpeg::DecodeFrame()
{
	ASSERT_M( m_ImageWaiting == FRAME_NONE, ssprintf("%i", m_ImageWaiting) );

	if( m_State == DECODER_QUIT )
		return false;
	CHECKPOINT;

	/* Read a frame. */
	int ret = m_pDecoder->GetFrame();
	if( ret == -1 )
		return false;

	if( m_bWantRewind && m_pDecoder->GetTimestamp() == 0 )
		m_bWantRewind = false; /* ignore */

	if( ret == 0 )
	{
		/* EOF. */
		if( !m_bLoop )
			return false;

		LOG->Trace( "File \"%s\" looping", GetID().filename.c_str() );
		m_bWantRewind = true;
	}

	if( m_bWantRewind )
	{
		m_bWantRewind = false;

		/* When resetting the clock, set it back by the length of the last frame,
		 * so it has a proper delay. */
		float fDelay = m_pDecoder->GetFrameDuration();

		/* Restart. */
		DestroyDecoder();
		CString sError = CreateDecoder();
		if( sError != "" )
			RageException::Throw( "Error rewinding stream %s: %s", GetID().filename.c_str(), sError.c_str() );

		m_pDecoder->Init();
		m_fClock = -fDelay;
		return false;
	}

	/* We got a frame. */
	m_ImageWaiting = FRAME_DECODED;

	return true;
}

/*
 * Call when m_ImageWaiting == FRAME_DECODED.
 * Returns:
 *  == 0 if the currently decoded frame is ready to be displayed
 *   > 0 (seconds) if it's not yet time to display;
 *  == -1 if we're behind and the frame should be skipped
 */
float MovieTexture_FFMpeg::CheckFrameTime()
{
	ASSERT_M( m_ImageWaiting == FRAME_DECODED, ssprintf("%i", m_ImageWaiting) );

	if( m_fRate == 0 )
		return 1;	// "a long time until the next frame"

	const float fOffset = (m_pDecoder->GetTimestamp() - m_fClock) / m_fRate;

	/* If we're ahead, we're decoding too fast; delay. */
	if( fOffset > 0.00001f )
	{
		if( m_bFrameSkipMode )
		{
			/* We're caught up; stop skipping frames. */
			LOG->Trace( "stopped skipping frames" );
			m_bFrameSkipMode = false;
		}
		return fOffset;
	}

	/*
	 * We're behind by -Offset seconds.  
	 *
	 * If we're just slightly behind, don't worry about it; we'll simply
	 * not sleep, so we'll move as fast as we can to catch up.
	 *
	 * If we're far behind, we're short on CPU.  Skip texture updates; this
	 * is a big bottleneck on many systems.
	 *
	 * If we hit a threshold, start skipping frames via #1.  If we do that,
	 * don't stop once we hit the threshold; keep doing it until we're fully
	 * caught up.
	 *
	 * We should try to notice if we simply don't have enough CPU for the video;
	 * it's better to just stay in frame skip mode than to enter and exit it
	 * constantly, but we don't want to do that due to a single timing glitch.
	 */
	const float FrameSkipThreshold = 0.5f;

	if( -fOffset >= FrameSkipThreshold && !m_bFrameSkipMode )
	{
		LOG->Trace( "(%s) Time is %f, and the movie is at %f.  Entering frame skip mode.",
			GetID().filename.c_str(), m_fClock, m_pDecoder->GetTimestamp());
		m_bFrameSkipMode = true;
	}

	if( m_bFrameSkipMode && m_pDecoder->m_stream->codec.frame_number % 2 )
		return -1; /* skip */
	
	return 0;
}

void MovieTexture_FFMpeg::DiscardFrame()
{
	ASSERT_M( m_ImageWaiting == FRAME_DECODED, ssprintf("%i", m_ImageWaiting) );
	m_ImageWaiting = FRAME_NONE;
}

void MovieTexture_FFMpeg::DecoderThread()
{
#if defined(_WINDOWS)
	/* Windows likes to boost priority when processes come out of a wait state.  We don't
	 * want that, since it'll result in us having a small priority boost after each movie
	 * frame, resulting in skips in the gameplay thread. */
	if( !SetThreadPriorityBoost(GetCurrentThread(), TRUE) && GetLastError() != ERROR_CALL_NOT_IMPLEMENTED )
		LOG->Warn( werr_ssprintf(GetLastError(), "SetThreadPriorityBoost failed") );
#endif

	CHECKPOINT;

	while( m_State != DECODER_QUIT )
	{
		if( m_ImageWaiting == FRAME_NONE )
			DecodeFrame();

		/* If we still have no frame, we're at EOF and we didn't loop. */
		if( m_ImageWaiting != FRAME_DECODED )
		{
			usleep( 10000 );
			continue;
		}

		const float fTime = CheckFrameTime();
		if( fTime == -1 )	// skip frame
		{
			DiscardFrame();
		}
		else if( fTime > 0 )		// not time to decode a new frame yet
		{
			/* This needs to be relatively short so that we wake up quickly 
			 * from being paused or for changes in m_fRate. */
			usleep( 10000 );
		}
		else // fTime == 0
		{
			{
				/* The only reason m_BufferFinished might be non-zero right now (before
				 * ConvertFrame()) is if we're quitting. */
				int n = m_BufferFinished.GetValue();
				ASSERT_M( n == 0 || m_State == DECODER_QUIT, ssprintf("%i, %i", n, m_State) );
			}
			ConvertFrame();

			/* We just went into FRAME_WAITING.  Don't actually check; the main thread
			 * will change us back to FRAME_NONE without locking, and poke m_BufferFinished.
			 * Don't time out on this; if a new screen has started loading, this might not
			 * return for a while. */
			m_BufferFinished.Wait( false );

			/* If the frame wasn't used, then we must be shutting down. */
			ASSERT_M( m_ImageWaiting == FRAME_NONE || m_State == DECODER_QUIT, ssprintf("%i, %i", m_ImageWaiting, m_State) );
		}
	}
	CHECKPOINT;
}

void MovieTexture_FFMpeg::Update(float fDeltaTime)
{
	/* We might need to decode more than one frame per update.  However, there
	 * have been bugs in ffmpeg that cause it to not handle EOF properly, which
	 * could make this never return, so let's play it safe. */
	int iMax = 4;
	while( --iMax )
	{
		if( !m_bThreaded )
		{
			/* If we don't have a frame decoded, decode one. */
			if( m_ImageWaiting == FRAME_NONE )
				DecodeFrame();

			/* If we have a frame decoded, see if it's time to display it. */
			if( m_ImageWaiting == FRAME_DECODED )
			{
				float fTime = CheckFrameTime();
				if( fTime > 0 )
					return;
				else if( fTime == -1 )
					DiscardFrame();
				else
					ConvertFrame();
			}
		}

		/* Note that if there's an image waiting, we *must* signal m_BufferFinished, or
		* the decoder thread may sit around waiting for it, even though Pause and Play
		* calls, causing the clock to keep running. */
		if( m_ImageWaiting != FRAME_WAITING )
			return;
		CHECKPOINT;

		UpdateFrame();
		
		if( m_bThreaded )
			m_BufferFinished.Post();
	}

	LOG->MapLog( "ffmpeg_looping", "MovieTexture_FFMpeg::Update looping" );
}

/* Call from the main thread when m_ImageWaiting == FRAME_WAITING to update the
 * texture.  Sets FRAME_NONE.  Does not signal m_BufferFinished. */
void MovieTexture_FFMpeg::UpdateFrame()
{
	ASSERT_M( m_ImageWaiting == FRAME_WAITING, ssprintf("%i", m_ImageWaiting) );

    /* Just in case we were invalidated: */
    CreateTexture();

	CHECKPOINT;
	DISPLAY->UpdateTexture(
        m_uTexHandle,
        m_pSurface,
        0, 0,
        m_iImageWidth, m_iImageHeight );
    CHECKPOINT;

	m_ImageWaiting = FRAME_NONE;
}

void MovieTexture_FFMpeg::Reload()
{
}

void MovieTexture_FFMpeg::StartThread()
{
	ASSERT( m_State == DECODER_QUIT );
	m_State = DECODER_RUNNING;
	m_DecoderThread.SetName( ssprintf("MovieTexture_FFMpeg(%s)", GetID().filename.c_str()) );
	
	if( m_bThreaded )
		m_DecoderThread.Create( DecoderThread_start, this );
}

void MovieTexture_FFMpeg::StopThread()
{
	if( !m_DecoderThread.IsCreated() )
		return;

	LOG->Trace("Shutting down decoder thread ...");

	m_State = DECODER_QUIT;

	/* Make sure we don't deadlock waiting for m_BufferFinished. */
	m_BufferFinished.Post();
	CHECKPOINT;
	m_DecoderThread.Wait();
	CHECKPOINT;
	
	m_ImageWaiting = FRAME_NONE;

	/* Clear the above post, if the thread didn't. */
	m_BufferFinished.TryWait();

	LOG->Trace("Decoder thread shut down.");
}

void MovieTexture_FFMpeg::SetPosition( float fSeconds )
{
    ASSERT( m_State != DECODER_QUIT );

	/* We can reset to 0, but I don't think this API supports fast seeking
	 * yet.  I don't think we ever actually seek except to 0 right now,
	 * anyway. XXX */
	if( fSeconds != 0 )
	{
		LOG->Warn( "MovieTexture_FFMpeg::SetPosition(%f): non-0 seeking unsupported; ignored", fSeconds );
		return;
	}

	LOG->Trace( "Seek to %f", fSeconds );
	m_bWantRewind = true;
}

/* This is used to decode data. */
void MovieTexture_FFMpeg::DecodeSeconds( float fSeconds )
{
	m_fClock += fSeconds * m_fRate;

	/* If we're not threaded, we want to be sure to decode any new frames now,
	 * and not on the next frame.  Update() may have already been called for this
	 * frame; call it again to be sure. */
	Update(0);
}

/*
 * (c) 2003-2004 Glenn Maynard
 * All rights reserved.
 * 
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, and/or sell copies of the Software, and to permit persons to
 * whom the Software is furnished to do so, provided that the above
 * copyright notice(s) and this permission notice appear in all copies of
 * the Software and that both the above copyright notice(s) and this
 * permission notice appear in supporting documentation.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT OF
 * THIRD PARTY RIGHTS. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR HOLDERS
 * INCLUDED IN THIS NOTICE BE LIABLE FOR ANY CLAIM, OR ANY SPECIAL INDIRECT
 * OR CONSEQUENTIAL DAMAGES, OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
 * OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */