[libdv-dev] deconding benchmark on ARM

[Oliver Z. <oz...@co...>]

Hi there!
I'm trying to do a benchmark for decoding DV data on an ARM machine
(arm920t core, 180MHz, 64MB SDRAM).

Here's the code:
--------------------------------------------------------
// decode.c
#include <stdio.h>
#include <sys/time.h>
#include <fcntl.h>
#include <libdv/dv.h>

#define READ_SIZE 120000 // PAL 144000
int main(int argc,char *argv[])
{
   dv_decoder_t *decoder = NULL;
   int fd, dec, count;
   unsigned char *pixels[3];
   int pitches[3];
   unsigned char video_buffer[720 * 576 * 3];
   unsigned char dv_buffer[READ_SIZE];
   struct timeval tv[3];
   double time = 0.0;
  
   if ((fd = open(argv[1],O_RDONLY)) < 0)
      printf("could not open file %s\n\n",argv[1]);
   else
      printf("opened file %s\n\n", argv[1]);
   pitches[0] = 720 * 3;
   pixels[0] = video_buffer;
   decoder = dv_decoder_new(TRUE, FALSE, FALSE);
   dec = count = 1;

   if (!decoder)
      printf("decoder new failed\n");

   if (READ_SIZE != read(fd, dv_buffer, READ_SIZE))
      printf("read failed\n");

   if (dv_parse_header(decoder, dv_buffer) < 0)
      printf("header parse error\n");

   printf("decoding...\n\n");
   gettimeofday(tv+0, NULL);
   dv_decode_full_frame(decoder, dv_buffer, e_dv_color_rgb, pixels,
pitches);

   while (dec) {
      if (READ_SIZE == read(fd, dv_buffer, READ_SIZE))
      {
         dv_decode_full_frame(decoder, dv_buffer, e_dv_color_rgb,
pixels, pitches);
         count++;
         //printf("frame no.: %d\n\n", count);
      } else dec = 0;
   } // while
   gettimeofday(tv+1, NULL);
   timersub(tv+1, tv+0, tv+2);
   time = tv[2].tv_sec + (tv[2].tv_usec / 1000000.0);
   printf("seconds: %f\n", time);
   printf("number of frames: %d\n", count);
   printf("resulting in %f fps\n", (double)count / time);
   close(fd);
   dv_decoder_free(decoder);
   return 0;
} // main
--------------------------------------------------

I configured libdv for arm:
./configure --disable-gtk --host=arm-linux --target=arm-linux

Cross-compiled with arm-linux-gcc (2.95.3) on my x86:
arm-linux-gcc -o arm-decode -ldv -O -O2 decode.c

Works so far but the performance is terrible. Decoding just one frame
takes several minutes (file pond.dv).
So my question is: is there any possiblity to improve speed?
Thank you!

Oliver