source: svn/trunk/newcon3bcm2_21bu/BSEAV/lib/bcmplayer/utils/rmscprevent.c

/***************************************************************************
 *     Copyright (c) 2006, Broadcom Corporation
 *     All Rights Reserved
 *     Confidential Property of Broadcom Corporation
 *
 *  THIS SOFTWARE MAY ONLY BE USED SUBJECT TO AN EXECUTED SOFTWARE LICENSE
 *  AGREEMENT  BETWEEN THE USER AND BROADCOM.  YOU HAVE NO RIGHT TO USE OR
 *  EXPLOIT THIS MATERIAL EXCEPT SUBJECT TO THE TERMS OF SUCH AN AGREEMENT.
 *
 * $brcm_Workfile: rmscprevent.c $
 * $brcm_Revision: Irvine_BSEAVSW_Devel/1 $
 * $brcm_Date: 4/12/06 2:20p $
 *
 * Module Description: remove start code emulation prevention from ES stream
 *
 * Revision History:
 *
 * $brcm_Log: /SetTop/bcmplayer/utils/rmscprevent.c $
 * 
 * Irvine_BSEAVSW_Devel/1   4/12/06 2:20p erickson
 * PR17108: added util to remove start code emulation prevention
 * 
 *************************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <assert.h>

int main(int argc, char **argv) {
        int fileoffset = 0;
#define BUFSIZE 4096
        unsigned char buf[BUFSIZE];
        int zero_count = 0;
        int curarg = 1;
        int possible_emulation = 0;

        if (curarg < argc && !strcmp(argv[curarg], "--help")) {
                fprintf(stderr, "Usage: rmscprevent <infile >outfile\n"
                "  Removes start code emulation prevention from ES streams. Uses stdin/stdout.\n");
                exit(0);
        }

        while (!feof(stdin)) {
                int i, n;
                
                n = fread(&buf[possible_emulation], 1, BUFSIZE-possible_emulation, stdin);
                if (n <= 0) break;
                        
                for (i=possible_emulation; i<n; i++) {
                        if (possible_emulation) {
                                if (buf[i] <= 3) {
                                        /* remove 0x03 */
                                        assert(buf[i-1] == 3);
                                        memmove(&buf[i-1], &buf[i], n-i);
                                        i--;
                                        n--;
                                        possible_emulation = 0;
                                        continue;
                                }
                        }
                        
                        possible_emulation = 0;
                        
                        switch (buf[i]) {
                        case 0:
                                if (zero_count >= 1)
                                        zero_count = 2;
                                else
                                        zero_count = 1;
                                break;
                        case 3:
                                if (zero_count == 2) {
                                        possible_emulation = 1;
                                }
                                /* fall through */
                        default:
                                zero_count = 0;
                                break;
                        }
                }
                fileoffset += n;

                /* don't write last byte of possible emulation byte */          
                if (possible_emulation) {
                        n--;
                }
                
                /* write the result out */
                fwrite(buf, 1, n, stdout);
                
                if (possible_emulation) {
                        /* move the 0x03 from the last byte to the first of the next buffer */
                        buf[0] = buf[n];
                        assert(buf[0] == 3);
                }
        }
        return 0;
}