/* =========================================================================== ITU-T Telecommunications Standardization Sector Document Q15-F-16 Study Group 16 Filename q15f16.c Video Coding Experts Group (Question 15) Generated: 28 Oct. '98 ---------------------------------------- Sixth meeting: Seoul, Korea, 3-6 November, 1998 pseudomux7.c ~~~~~~~~~~~~ Simple video packet mux simulator. Approximates AL3 mux of H.223 Annex B. Source: ~~~~~~~ Gary Sullivan Tel: +1 978 623 4324 PictureTel Corp. Fax: +1 978 749 2804 100 Minuteman Rd. Email: garys@pictel.com Andover MA 01810 USA Written with help from Stephan Wenger, Ari Hourunranta, Simao Campos-Neto, and Maximillian Luttrell. Purpose: Information ~~~~~~~~ History: ~~~~~~~~ 08.Oct.98 V.0.04 Changed CRC generator; solved MSDOS warnings with MSC. 09.Oct.98 V.0.05 Warnings solved (with gcc -Wall (in a HPUX system): removed unused CRC polynomial tables crctab_xmodem[], crctab_arc[]; replaced %d with %ld in fprint()'s. 22.Oct.98 V.0.06 Changed to send a pseudo-audio packet first. Reduced MAX_PACKET_SIZE to 254 (max AL3 MPL value). CRC length for audio reduced to 1 byte (AL2 CRC length). Corrected time computation to include video overhead. Increased amount of final summary information reported. 28.Oct.98 V.0.07 Increased AUDIO_PACKET_SIZE to 24 bytes (to reflect G.723.1 high bit-rate operation). Added optional ErrStart command-line parameter. Submitted as contribution Q15-F-16 to ITU-T Q.15/SG16 meeting in Seoul, Korea, 3-6 Nov. 98. =========================================================================== */ #include #include #include typedef unsigned char byte; typedef unsigned short unt16; typedef short int16; typedef long int32; /* initialization value of CRC */ #define INIT_CRC_C ((unt16) 0xFFFF) /* --------------------------------------------------------------------------- unt16 updcrc (unt16 icrc, unsigned char *icp, int icnt, unt16 *crctab, ~~~~~~~~~~~~ char swapped); Description: ~~~~~~~~~~~~ Calculate, intelligently, the CRC-16 of a dataset incrementally given a buffer full at a time. The parameters on which the function relies are: Parameter CCITT XMODEM ARC --------- ------ ------ ---- the polynomial P 0x1021 0x1021 A001 initial CRC value: 0xFFFF 0 0 bit-order swap No (0) Yes (1) Yes (1) bits in CRC: 16 16 16 Usage: ~~~~~~ newcrc = updcrc( oldcrc, bufadr, buflen, crctab, swapped) unt16 oldcrc; int buflen; char *bufadr; unt16 *crctab; char swapped; Notes: Regards the data stream as an integer whose MSB is the MSB of the first byte recieved. This number is 'divided' (using xor instead of subtraction) by the crc-polynomial P. XMODEM does things a little differently, essentially treating the LSB of the first data byte as the MSB of the integer. Original Author: ~~~~~~~~~~~~~~~~ Mark G. Mendel, 7/86 UUCP: ihnp4!umn-cs!hyper!mark, GEnie: mgm [ Original code available in comp.sources.unix volume 6 (1989) ] History: ~~~~~~~~ xx.Jul.86 v1.0 Release by the author [posted to c.s.misc in 1989] 01.Sep.93 v1.0a Adapted by Simao to be used in the x{en,de}code.c. 08.Oct.98 v1.0b Adopted into pseudo-mux simulator by Gary (garys@pictel.com) --------------------------------------------------------------------------- */ #define BPS 8 /* bits per sample */ #define CRCW 16 /* crc width */ /* Table for CCITT CRCs */ static unt16 crctab_ccitt[1 << BPS] = { 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7, 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF, 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6, 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE, 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485, 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D, 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4, 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC, 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823, 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B, 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12, 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A, 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41, 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49, 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70, 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78, 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F, 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067, 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E, 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256, 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D, 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405, 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C, 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634, 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB, 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3, 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A, 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92, 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9, 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1, 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8, 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0, }; /* -------------- Begin of function updcrc() ---------------------- */ unt16 updcrc(icrc, icp, icnt, crctab, swapped) unt16 icrc, *crctab; unsigned char *icp; int icnt; char swapped; { register unt16 crc = icrc; register unsigned char *cp = icp; register int cnt = icnt; if (swapped) while (cnt--) crc = (crc >> BPS) ^ crctab[(crc & ((1 << BPS) - 1)) ^ *cp++]; else while (cnt--) crc = (crc << BPS) ^ crctab[(crc >> (CRCW - BPS)) ^ *cp++]; return (crc); } /* .......................... End of updcrc() ............................ */ #define MAX_PACKET_SIZE 254 /* bytes */ #define AUDIO_TIME_INTERVAL 0.030 /* seconds */ #define AUDIO_PACKET_SIZE 24 /* bytes (not including overhead) */ #define SYNC_SIZE 2 /* bytes */ #define HEADER_SIZE 3 /* bytes */ #define AL2_CRC_SIZE 1 /* bytes */ #define AL3_CRC_SIZE 2 /* bytes */ #define AL2_OVERHEAD_SIZE (SYNC_SIZE + HEADER_SIZE + AL2_CRC_SIZE) #define AL3_OVERHEAD_SIZE (SYNC_SIZE + HEADER_SIZE + AL3_CRC_SIZE) #define MAX_SYNC_ERRORS 3 #define MAX_HEADER_ERRORS 2 /* The 2 byte sync, listed from MSB to LSB is 0100110111100001 (0x4DE1) */ /* The 3 byte AL2 mux header we are using contains the following: bits contents explanation 0-3 MC Multiplex Code, describes multiplex scheme of packet 4-11 MPL Multiplex Payload Length, the length of the data field 12-23 golay (24,12) Golay block code which codes combined MC+MPL */ int main(int ac, char *av[]) { byte PacketData[MAX_PACKET_SIZE], *errors, ebyte, CRCcheckFail; int32 esize, eposition, j, k, SyncErrorCount, HeaderErrorCount, TotalBytes; int32 VideoPacketSize, TotalBitRate, TotalVideoBytes, VideoPacketNumber; unt16 transmitted_crc, received_crc, rcvr_computed_crc; FILE *efile; double time_since_audio_sent, time_duration_of_audio_packet; if(ac != 3 && ac != 4) { fprintf(stderr, "Usage: pseudomux ErrorFile TotalBitRate [ErrStart]"); fprintf(stderr, " output_packets\n"); fprintf(stderr, "\n"); fprintf(stderr, "Error patterns are .bin files\n"); fprintf(stderr, "\n"); fprintf(stderr, "If there is more input data than the length of the\n"); fprintf(stderr, "error pattern file, then the pattern will be used\n"); fprintf(stderr, "repetitively by circular wrapping\n"); fprintf(stderr, "\n"); fprintf(stderr, "TotalBitRate (integer) is used to determine when to\n"); fprintf(stderr, "insert periodic audio packets\n"); fprintf(stderr, "\n"); fprintf(stderr, "ErrStart (integer) is used to specify the starting\n"); fprintf(stderr, "byte number in the error pattern file (default = 0).\n"); fprintf(stderr, "Note that all bytes are used when wrapping, but\n"); fprintf(stderr, "ErrStart bytes are jumped over at start-up\n"); fprintf(stderr, "\n"); fprintf(stderr, "Input packets (from stdin) are each prefaced by\n"); fprintf(stderr, "packet length in bytes (integer)\n"); fprintf(stderr, "\n"); fprintf(stderr, "Output (to stdout) for each (non-lost) packet contains:\n"); fprintf(stderr, " CRCcheckFail flag (byte),\n"); fprintf(stderr, " packet length (integer), and\n"); fprintf(stderr, " packet data (with errors applied)\n"); fprintf(stderr, "\n"); fprintf(stderr, "Total number of video bytes used including packet\n"); fprintf(stderr, "overhead is written to stderr\n"); fprintf(stderr, "\n"); exit(-1); } if((efile = fopen(av[1], "rb")) == NULL) { fprintf(stderr, "gobloss: cannot open %s\n", av[1]); exit(-2); } TotalBitRate = atoi(av[2]); if(ac == 4) eposition = atoi(av[3]); else eposition = 0; /* determine size of error pattern file and read it into errors buffer */ if(fseek(efile, 0L, SEEK_END)) { fprintf(stderr, "fseek failed\n"); exit(-3); } if((esize = ftell(efile)) == -1) { fprintf(stderr, "ftell returns -1"); exit(-4); } fseek(efile, 0L, SEEK_SET); if((errors = (byte *)malloc(esize)) == NULL) { fprintf(stderr, "cannot malloc %ld bytes for error patterns\n", esize); exit(-5); } if(fread(errors, esize, 1, efile) != 1) { fprintf(stderr, "error while reading error patterns\n"); exit(-6); } fclose(efile); time_duration_of_audio_packet = (AUDIO_PACKET_SIZE + AL2_OVERHEAD_SIZE) * 8.0 / TotalBitRate; for(VideoPacketNumber = 0, TotalBytes = 0, TotalVideoBytes = 0, time_since_audio_sent = AUDIO_TIME_INTERVAL; fread(&VideoPacketSize, sizeof(VideoPacketSize), 1, stdin) == 1; VideoPacketNumber++, TotalVideoBytes += VideoPacketSize, TotalBytes += VideoPacketSize + AL3_OVERHEAD_SIZE, time_since_audio_sent += (VideoPacketSize + AL3_OVERHEAD_SIZE) * 8.0 / TotalBitRate) { if(VideoPacketSize > MAX_PACKET_SIZE) { fprintf(stderr, "packet size (%ld) too large\n", VideoPacketSize); exit(-7); } if(fread(PacketData, sizeof(byte), VideoPacketSize, stdin) != (size_t)VideoPacketSize) { fprintf(stderr, "error reading video packet of %ld bytes\n", VideoPacketSize); exit(-8); } /* send audio when necessary (and account for time to send it) */ while(time_since_audio_sent >= AUDIO_TIME_INTERVAL) { TotalBytes += AUDIO_PACKET_SIZE + AL2_OVERHEAD_SIZE; eposition += AUDIO_PACKET_SIZE + AL2_OVERHEAD_SIZE; if(eposition >= esize) eposition -= esize; time_since_audio_sent -= AUDIO_TIME_INTERVAL; time_since_audio_sent += time_duration_of_audio_packet; } /* discard SYNC_SIZE bytes while counting errors in them */ for(j=0, SyncErrorCount=0; j> k) & 1) SyncErrorCount++; } /* discard HEADER_SIZE bytes while counting errors in them */ for(j=0, HeaderErrorCount=0; j> k) & 1) HeaderErrorCount++; } /* calculate packet CRC to be transmitted */ transmitted_crc = updcrc(INIT_CRC_C, PacketData, VideoPacketSize, crctab_ccitt, 0); /* apply errors to video packet */ for(j=0; j