[mpeg2-dev] mpeg2_parse always returns STATE_INVALID

[Daniel T. <dt....@gm...>]

Hi,

I've just compiled libmpeg2 for an embedded platform and have written some code for decoding. But the call to mpeg2_parse in this code seems to always return STATE_INVALID. 

int play(FILE * mpgfile)
{
	mpeg2dec_t * decoder;
   const mpeg2_info_t * info;
   mpeg2_state_t state;
   size_t size = 1;
	unsigned char *buffer = malloc(BUFFER_SIZE);
	
	char debug[20];
	if (!buffer) {
		show_msgbox("NspireMoviePlayer","NULL ptr from Malloc");
		return 1;
	}
	
	decoder = mpeg2_init ();
   if (!decoder) {
   	show_msgbox("NspireMoviePlayer","Could not init mpeg2");
		return 1;
	}

   info = mpeg2_info (decoder);
	do
	{
		state = mpeg2_parse (decoder);
		switch (state) {
			case STATE_BUFFER:
		    	size = fread (buffer, 1, BUFFER_SIZE, mpgfile);
		    	mpeg2_buffer (decoder, buffer, buffer + size);
		    	break;
			case STATE_SEQUENCE:
		    	mpeg2_convert (decoder, mpeg2convert_rgb24, NULL);
		    	settimerperiod(info->sequence->frame_period);
		    	break;
			case STATE_SLICE:
			case STATE_END:
				if (info->sequence->width  != SCREEN_WIDTH ||
					info->sequence->height != SCREEN_HEIGHT)
				{
					show_msgbox("NspireMoviePlayer","Screen size mismatch");
					goto die;
				}
				else {
					waittimerperiod();
					renderframe(info->display_fbuf->buf[0]);
				}
				break;
			case STATE_INVALID:
				goto die;
		    	break;
			default:
		    	break;
		}
	} while(size);
	
	mpeg2_close(decoder);
	return 0;
	
	die:
	mpeg2_close(decoder);
	return 1;
}

I dug around decode.c and added some debugging messages and it seems it's conking out in this piece of code at the bottom of mpeg2_parse:

mpeg2dec->action = mpeg2_seek_header;
   switch (mpeg2dec->code) {
   case 0x00:
   show_msgbox("libmpeg2","case 0 mpeg2dec->code");
	return mpeg2dec->state;
   case 0xb3:
   case 0xb7:
   case 0xb8:
   show_msgbox("libmpeg2","case b8 mpeg2dec->code");
	return (mpeg2dec->state == STATE_SLICE) ? STATE_SLICE : STATE_INVALID;
   default:
	mpeg2dec->action = seek_chunk;
	show_msgbox("libmpeg2","default mpeg2dec->code"); // This is where it returns
	return STATE_INVALID;
   }

Does anyone have any ideas on what could be causing this? The code isn't very well documented and it's hard to follow.

Cheers,