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MPEGSource.cpp

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/**************************************************************************
 *
 * Source code for Real Time Image Library (libRTImage)
 *
 * Leeds Vision Group give permission for this code to be copied, modified 
 * and distributed within the University of Leeds subject to the following 
 * conditions:-
 *
 * - The code is not to be used for commercial gain.
 * - The code and use thereof will be attributed to the author where
 *   appropriate (inluding demonstrations which rely on it's use).
 * - All modified, distributions of the source files will retain this header.
 *
 ****************************************************************************/
 
#define ORIGINAL_VER
 
#include "ccvt/conv.h"
#include "MPEGSource.h"

//char *Y, *U, *V ; // commented out by cjn 14-09-01
                    // already declared in class MPEGSource

MPEGSource::MPEGSource(char* path)
{
        // check the files signature is valid
        if (!mpeg3_check_sig(path))
                throw "incompatible mpeg file";
        
        // open the MPEG file
        file = mpeg3_open(path);
        if (file == NULL)
                throw "error opening mpeg file";

        // check that it is a video MPEG file
        if (!mpeg3_has_video(file))
                throw "non-video MPEG file";
                        
        
        width  = mpeg3_video_width(file, 0);
        height = mpeg3_video_height(file, 0);
        frames = mpeg3_video_frames(file, 0);
        framerate = mpeg3_frame_rate(file, 0);

        // allocate memory for rgb rows
        buff = new (unsigned char*)[height];
        for (unsigned int i = 0; i < height - 1; i++)
                buff[i] = new (unsigned char)[width*3];
        
        // last row need space for mmx scratch area
        buff[height - 1] = new (unsigned char)[width*3 + 4];

        // Allocate memory for YUV data
        Y = new char[width*height] ;
        U = new char[width*height/4] ;
        V = new char[width*height/4] ;
        
        // default palette type for this ImageSource is colour 
        type = Image::COLOUR;
}


MPEGSource::~MPEGSource()
{
        mpeg3_close(file);

        // free the memory for each of the rows
        for (unsigned int i = 0; i < height; i++)
                delete [] buff[i];
        
        // free the rest of the memory
        delete [] buff;
}


ImageSource& MPEGSource::operator >> (ImageRGB& img) 
{
        // read the frame to a temporary buffer
        mpeg3_read_frame(file, buff, 
                         0, 0,
                         width, height,
                         width, height,
                         MPEG3_RGB888, 0);

        // convert the frame to rgb96
        conv_rgb24_rgb96(width, height, buff, img.data[0]);

        return *this;
}


ImageSource& MPEGSource::operator >> (ImageGrey& img)
{
        // No longer needed
        // char *Y, *U, *V;     // temp pointers for yuv frame information

        // set the pointers to point to y, u, and v buffers
        // Originally used the faster:
        // mpeg3_read_yuvframe_ptr(file, &Y, &U, &V, 0);
        // But this doesn't seem to work

 
        mpeg3_read_yuvframe(file,
                            Y,U,V,
                            0, 0,
                            width, height,
                            0);

        // convert the Y (luminance) information to 32bit greyscale
        // Originally 
        conv_420p_grey(width, height, Y, img.brightness);


        return *this;
}


ImageSource& MPEGSource::operator >> (Image& img) 
{
        (type == Image::COLOUR) ? *this >> (ImageRGB&)img
                                : *this >> (ImageGrey&)img;
                
        return *this;
}

int  MPEGSource::get_no_frames()
{
return (int) frames;
}

void MPEGSource::get_size(unsigned int& w, unsigned int& h)
{
        w = width; 
        h = height;
}

int MPEGSource::set_frame(long frame_no)
{
    return mpeg3_set_frame(file, frame_no, 0) ;
}

void MPEGSource::get_framerate(float& fr_rate)
{
    fr_rate = framerate;
}

bool MPEGSource::eof() const
{
    return (bool)(mpeg3_end_of_video(file, 0));
}

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