[libdv-dev] Image Processing using Firewire

[Juan C. <elg...@ya...>]

Hi,

I have a Sony VX2000 DV camera which supports firewire
connection. What I would like to do is capture frames
continuously from the firewire and save those frames
to my hard disk for image processing. After some
research, I found that to capture the raw DV data
libraw1394 library in linux has to be used and to
decode the data libdv should be used. I wrote a small
code for this purpose, however I am getting weird,
random colored images. I also looked at the examples
that come from libdv source files; however no luck at
all. Can somebody please look at my code and tell me
what I am doing wrong? I got stuck on this and I can't
start my research area. Thanks a lot for your
responses in advance. Here is my code: 

#define BUFFER 1000
#define PACKET_MAX 4096

#include <iostream>
#include
"/home/elgitaro/libraw1394-1.1.0/src/raw1394.h"
#include <libdv/dv.h>
using namespace std;
u_int64_t listen_channels;
raw1394handle_t handle;
int num_of_cards;
struct raw1394_portinfo pinf[ 16 ];
quadlet_t buffer;
dv_decoder_t *mydecoder;
raw1394_iso_dma_recv_mode mode;	
int pitches[3];
unsigned char *pixels[1];
char filename[1024];
void saveasppm(unsigned char**,dv_decoder_t);
unsigned char dv_buffer[144000];
unsigned char video_buffer[720 * 576 * 3];
int *isPAL = FALSE;


static enum raw1394_iso_disposition 
iso_handler(raw1394handle_t handle, unsigned char
*data, 
        unsigned int length, unsigned char channel,
        unsigned char tag, unsigned char sy, unsigned
int cycle, 
        unsigned int dropped)
{
	if ( length > 16 )
	{
		memcpy(dv_buffer,data,120000);
		unsigned char * p = ( unsigned char* ) & data[ 3 ];
        if (p[ 3 ] & 0x80) { //Check if the signal is
PAL
				cout << "Pal" << endl;
				mydecoder->clamp_luma = FALSE;
				mydecoder->clamp_chroma = FALSE;
				dv_reconfigure(FALSE, FALSE);
                memcpy(dv_buffer + 120000, data,
144000 - 120000);
		}
		if((dv_parse_header(mydecoder, dv_buffer)) < 0){
      	cout << "dv_parse_header failed" << endl;
		return RAW1394_ISO_OK;	
    }
		else
			cout << "Parse Header successful" << endl; 
	
	pitches[0] = 720 * 3; //mydecoder->width * 3;
	//dv_parse_packs (mydecoder, dv_buffer);
    dv_decode_full_frame(mydecoder,
			 dv_buffer,
			 e_dv_color_rgb, /* RGB */
			 pixels,
			 pitches);
	FILE *fp;
	sprintf(filename, "outbuf.ppm");
    fp = fopen(filename, "wb");
    if(fp != NULL)
		{
      fprintf(fp, "P6\n%d
%d\n255\n",mydecoder->width,mydecoder->height);
      fwrite(pixels[0], 1,
3*mydecoder->width*mydecoder->height, fp);
      fclose(fp);	
		}
	 }	
	return RAW1394_ISO_OK;
}

int main()
{
	pixels[0] = video_buffer;
	handle = raw1394_new_handle();
	if (handle==0)
		cout << "No handle has been created" << endl;
	else
		cout << "Handle is: " << handle << endl;
	//num_of_cards = raw1394_get_port_info( handle, pinf,
16 );
	//cout << "Number of ports: " << num_of_cards <<
endl;
	//cout << "Port info: " << pinf[0].name << " . " <<
pinf[0].nodes << endl;
		if (raw1394_set_port(handle, 0) < 0) 
			{
				cout << "Couldn't set port";
				exit(1);
		}
	mode = RAW1394_DMA_DEFAULT;
		
	raw1394_iso_multichannel_recv_init(handle,
iso_handler,
                        BUFFER, 2048, -1);
		listen_channels = ~0ULL;
		raw1394_iso_recv_set_channel_mask(handle,
listen_channels);
		
	
	 
	/* create dv decoder */
	cout << "creating the dv decoder" << endl; 
  	mydecoder = dv_decoder_new(FALSE, FALSE, FALSE);
	if(mydecoder == NULL)
    	cout << "dv_decoder_new failed" << endl;
	mydecoder->video->arg_monochrome = 0; /* color frames
*/
  	mydecoder->quality = 
    mydecoder->video->quality = DV_QUALITY_BEST; /*
color and fine scale */



	
	if(raw1394_iso_recv_start(handle, -1, -1, 0)==0)
		cout << "iso_recv_start success" << endl;
    //while (raw1394_loop_iterate(handle) == 0);
	//for (int i=0; i<5; i++)
	raw1394_loop_iterate(handle);
	
	
	dv_decoder_free(mydecoder);
	raw1394_iso_shutdown(handle);
	exit(1);		
}



		
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