libmpdemux/yuv4mpeg.c

   1 /*
   2  *  yuv4mpeg.c:  Functions for reading and writing "new" YUV4MPEG streams
   3  *
   4  *  Copyright (C) 2001 Matthew J. Marjanovic <maddog@mir.com>
   5  *
   6  *  This file is part of the MJPEG Tools package (mjpeg.sourceforge.net).
   7  *  Ported to mplayer by Rik Snel <rsnel@cube.dyndns.org>
   8  *
   9  *  This program is free software; you can redistribute it and/or
  10  *  modify it under the terms of the GNU General Public License
  11  *  as published by the Free Software Foundation; either version 2
  12  *  of the License, or (at your option) any later version.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program; if not, write to the Free Software
  21  *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  *
  23  */
  24
  25 #include "config.h"
  26
  27 #include <unistd.h>
  28 #include <stdio.h>
  29 #include <stdlib.h>
  30 #include <string.h>
  31 #include "yuv4mpeg.h"
  32 #include "yuv4mpeg_intern.h"
  33 #include "mp_msg.h"
  34 #include "libavutil/attributes.h"
  35
  36 static int _y4mparam_allow_unknown_tags = 1;  /* default is forgiveness */
  37
  38 static void *(*_y4m_alloc)(size_t bytes) = malloc;
  39 static void (*_y4m_free)(void *ptr) = free;
  40
  41 int y4m_allow_unknown_tags(int yn) {
  42         int old = _y4mparam_allow_unknown_tags;
  43         if (yn >= 0) _y4mparam_allow_unknown_tags = (yn) ? 1 : 0;
  44         return old;
  45 }
  46
  47
  48
  49 /*************************************************************************
  50  *
  51  * Convenience functions for fd read/write
  52  *
  53  *   - guaranteed to transfer entire payload (or fail)
  54  *   - returns:
  55  *               0 on complete success
  56  *               +(# of remaining bytes) on eof (for y4m_read)
  57  *               -(# of rem. bytes) on error (and ERRNO should be set)
  58  *
  59  *************************************************************************/
  60
  61
  62 ssize_t y4m_read(stream_t *s, char *buf, size_t len)
  63 {
  64    ssize_t n;
  65
  66    while (len > 0) {
  67      n = stream_read(s, buf, len);
  68      if (n <= 0) {
  69        /* return amount left to read */
  70        if (n == 0)
  71          return len;  /* n == 0 --> eof */
  72        else
  73          return -len; /* n < 0 --> error */
  74      }
  75      buf += n;
  76      len -= n;
  77    }
  78    return 0;
  79 }
  80
  81
  82 #if 0 /* not needed */
  83 ssize_t y4m_write(int fd, char *buf, size_t len)
  84 {
  85    ssize_t n;
  86
  87    while (len > 0) {
  88      n = write(fd, buf, len);
  89      if (n < 0) return -len;  /* return amount left to write */
  90      buf += n;
  91      len -= n;
  92    }
  93    return 0;
  94 }
  95 #endif
  96
  97
  98 /*************************************************************************
  99  *
 100  * "Extra tags" handling
 101  *
 102  *************************************************************************/
 103
 104
 105 static char *y4m_new_xtag(void)
 106 {
 107   return _y4m_alloc(Y4M_MAX_XTAG_SIZE);
 108 }
 109
 110
 111 void y4m_init_xtag_list(y4m_xtag_list_t *xtags)
 112 {
 113   int i;
 114   xtags->count = 0;
 115   for (i = 0; i < Y4M_MAX_XTAGS; i++) {
 116     xtags->tags[i] = NULL;
 117   }
 118 }
 119
 120
 121 void y4m_fini_xtag_list(y4m_xtag_list_t *xtags)
 122 {
 123   int i;
 124   for (i = 0; i < Y4M_MAX_XTAGS; i++) {
 125     if (xtags->tags[i] != NULL) {
 126       _y4m_free(xtags->tags[i]);
 127       xtags->tags[i] = NULL;
 128     }
 129   }
 130   xtags->count = 0;
 131 }
 132
 133
 134 void y4m_copy_xtag_list(y4m_xtag_list_t *dest, const y4m_xtag_list_t *src)
 135 {
 136   int i;
 137   for (i = 0; i < src->count; i++) {
 138     if (dest->tags[i] == NULL)
 139       dest->tags[i] = y4m_new_xtag();
 140     strncpy(dest->tags[i], src->tags[i], Y4M_MAX_XTAG_SIZE);
 141   }
 142   dest->count = src->count;
 143 }
 144
 145
 146
 147 #if 0
 148 static int y4m_snprint_xtags(char *s, int maxn, y4m_xtag_list_t *xtags)
 149 {
 150   int i, room;
 151
 152   for (i = 0, room = maxn - 1; i < xtags->count; i++) {
 153     int n = snprintf(s, room + 1, " %s", xtags->tags[i]);
 154     if ((n < 0) || (n > room)) return Y4M_ERR_HEADER;
 155     s += n;
 156     room -= n;
 157   }
 158   s[0] = '\n';  /* finish off header with newline */
 159   s[1] = '\0';  /* ...and end-of-string           */
 160   return Y4M_OK;
 161 }
 162 #endif
 163
 164
 165 int y4m_xtag_count(const y4m_xtag_list_t *xtags)
 166 {
 167   return xtags->count;
 168 }
 169
 170
 171 const char *y4m_xtag_get(const y4m_xtag_list_t *xtags, int n)
 172 {
 173   if (n >= xtags->count)
 174     return NULL;
 175   else
 176     return xtags->tags[n];
 177 }
 178
 179
 180 int y4m_xtag_add(y4m_xtag_list_t *xtags, const char *tag)
 181 {
 182   if (xtags->count >= Y4M_MAX_XTAGS) return Y4M_ERR_XXTAGS;
 183   if (xtags->tags[xtags->count] == NULL) {
 184     xtags->tags[xtags->count] = y4m_new_xtag();
 185   }
 186   strncpy(xtags->tags[xtags->count], tag, Y4M_MAX_XTAG_SIZE);
 187   (xtags->count)++;
 188   return Y4M_OK;
 189 }
 190
 191
 192 int y4m_xtag_remove(y4m_xtag_list_t *xtags, int n)
 193 {
 194   int i;
 195   char *q;
 196
 197   if ((n < 0) || (n >= xtags->count)) return Y4M_ERR_RANGE;
 198   q = xtags->tags[n];
 199   for (i = n; i < (xtags->count - 1); i++)
 200     xtags->tags[i] = xtags->tags[i+1];
 201   xtags->tags[i] = q;
 202   (xtags->count)--;
 203   return Y4M_OK;
 204 }
 205
 206
 207 int y4m_xtag_clearlist(y4m_xtag_list_t *xtags)
 208 {
 209   xtags->count = 0;
 210   return Y4M_OK;
 211 }
 212
 213
 214 int y4m_xtag_addlist(y4m_xtag_list_t *dest, const y4m_xtag_list_t *src)
 215 {
 216   int i, j;
 217
 218   if ((dest->count + src->count) > Y4M_MAX_XTAGS) return Y4M_ERR_XXTAGS;
 219   for (i = dest->count, j = 0;
 220        j < src->count;
 221        i++, j++) {
 222     if (dest->tags[i] == NULL)
 223       dest->tags[i] = y4m_new_xtag();
 224     strncpy(dest->tags[i], src->tags[i], Y4M_MAX_XTAG_SIZE);
 225   }
 226   dest->count += src->count;
 227   return Y4M_OK;
 228 }
 229
 230
 231 /*************************************************************************
 232  *
 233  * Creators/destructors for y4m_*_info_t structures
 234  *
 235  *************************************************************************/
 236
 237
 238 void y4m_init_stream_info(y4m_stream_info_t *info)
 239 {
 240   if (info == NULL) return;
 241   /* initialize info */
 242   info->width = Y4M_UNKNOWN;
 243   info->height = Y4M_UNKNOWN;
 244   info->interlace = Y4M_UNKNOWN;
 245   info->framerate = y4m_fps_UNKNOWN;
 246   info->sampleaspect = y4m_sar_UNKNOWN;
 247   y4m_init_xtag_list(&(info->x_tags));
 248 }
 249
 250
 251 void y4m_copy_stream_info(y4m_stream_info_t *dest, y4m_stream_info_t *src)
 252 {
 253   if ((dest == NULL) || (src == NULL)) return;
 254   /* copy info */
 255   dest->width = src->width;
 256   dest->height = src->height;
 257   dest->interlace = src->interlace;
 258   dest->framerate = src->framerate;
 259   dest->sampleaspect = src->sampleaspect;
 260   y4m_copy_xtag_list(&(dest->x_tags), &(src->x_tags));
 261 }
 262
 263
 264 void y4m_fini_stream_info(y4m_stream_info_t *info)
 265 {
 266   if (info == NULL) return;
 267   y4m_fini_xtag_list(&(info->x_tags));
 268 }
 269
 270
 271 void y4m_si_set_width(y4m_stream_info_t *si, int width)
 272 {
 273   si->width = width;
 274   si->framelength = (si->height * si->width) * 3 / 2;
 275 }
 276
 277 int y4m_si_get_width(y4m_stream_info_t *si)
 278 { return si->width; }
 279
 280 void y4m_si_set_height(y4m_stream_info_t *si, int height)
 281 {
 282   si->height = height;
 283   si->framelength = (si->height * si->width) * 3 / 2;
 284 }
 285
 286 int y4m_si_get_height(y4m_stream_info_t *si)
 287 { return si->height; }
 288
 289 void y4m_si_set_interlace(y4m_stream_info_t *si, int interlace)
 290 { si->interlace = interlace; }
 291
 292 int y4m_si_get_interlace(y4m_stream_info_t *si)
 293 { return si->interlace; }
 294
 295 void y4m_si_set_framerate(y4m_stream_info_t *si, y4m_ratio_t framerate)
 296 { si->framerate = framerate; }
 297
 298 y4m_ratio_t y4m_si_get_framerate(y4m_stream_info_t *si)
 299 { return si->framerate; }
 300
 301 void y4m_si_set_sampleaspect(y4m_stream_info_t *si, y4m_ratio_t sar)
 302 { si->sampleaspect = sar; }
 303
 304 y4m_ratio_t y4m_si_get_sampleaspect(y4m_stream_info_t *si)
 305 { return si->sampleaspect; }
 306
 307 int y4m_si_get_framelength(y4m_stream_info_t *si)
 308 { return si->framelength; }
 309
 310 y4m_xtag_list_t *y4m_si_xtags(y4m_stream_info_t *si)
 311 { return &(si->x_tags); }
 312
 313
 314
 315 void y4m_init_frame_info(y4m_frame_info_t *info)
 316 {
 317   if (info == NULL) return;
 318   /* initialize info */
 319   y4m_init_xtag_list(&(info->x_tags));
 320 }
 321
 322
 323 void y4m_copy_frame_info(y4m_frame_info_t *dest, y4m_frame_info_t *src)
 324 {
 325   if ((dest == NULL) || (src == NULL)) return;
 326   /* copy info */
 327   y4m_copy_xtag_list(&(dest->x_tags), &(src->x_tags));
 328 }
 329
 330
 331 void y4m_fini_frame_info(y4m_frame_info_t *info)
 332 {
 333   if (info == NULL) return;
 334   y4m_fini_xtag_list(&(info->x_tags));
 335 }
 336
 337
 338
 339 /*************************************************************************
 340  *
 341  * Tag parsing
 342  *
 343  *************************************************************************/
 344
 345 int y4m_parse_stream_tags(char *s, y4m_stream_info_t *i)
 346 {
 347   char *token, *value;
 348   char tag;
 349   int err;
 350
 351   /* parse fields */
 352   for (token = strtok(s, Y4M_DELIM);
 353        token != NULL;
 354        token = strtok(NULL, Y4M_DELIM)) {
 355     if (token[0] == '\0') continue;   /* skip empty strings */
 356     tag = token[0];
 357     value = token + 1;
 358     switch (tag) {
 359     case 'W':  /* width */
 360       i->width = atoi(value);
 361       if (i->width <= 0) return Y4M_ERR_RANGE;
 362       break;
 363     case 'H':  /* height */
 364       i->height = atoi(value);
 365       if (i->height <= 0) return Y4M_ERR_RANGE;
 366       break;
 367     case 'F':  /* frame rate (fps) */
 368       if ((err = y4m_parse_ratio(&(i->framerate), value)) != Y4M_OK)
 369         return err;
 370       if (i->framerate.n < 0) return Y4M_ERR_RANGE;
 371       break;
 372     case 'I':  /* interlacing */
 373       switch (value[0]) {
 374       case 'p':  i->interlace = Y4M_ILACE_NONE; break;
 375       case 't':  i->interlace = Y4M_ILACE_TOP_FIRST; break;
 376       case 'b':  i->interlace = Y4M_ILACE_BOTTOM_FIRST; break;
 377       case '?':
 378       default:
 379         i->interlace = Y4M_UNKNOWN; break;
 380       }
 381       break;
 382     case 'A':  /* sample (pixel) aspect ratio */
 383       if ((err = y4m_parse_ratio(&(i->sampleaspect), value)) != Y4M_OK)
 384         return err;
 385       if (i->sampleaspect.n < 0) return Y4M_ERR_RANGE;
 386       break;
 387     case 'X':  /* 'X' meta-tag */
 388       if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
 389       break;
 390     default:
 391       /* possible error on unknown options */
 392       if (_y4mparam_allow_unknown_tags) {
 393         /* unknown tags ok:  store in xtag list and warn... */
 394         if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
 395         mp_msg(MSGT_DEMUX, MSGL_WARN, "Unknown stream tag encountered:  '%s'\n", token);
 396       } else {
 397         /* unknown tags are *not* ok */
 398         return Y4M_ERR_BADTAG;
 399       }
 400       break;
 401     }
 402   }
 403   /* Error checking... width and height must be known since we can't
 404    * parse without them
 405    */
 406   if( i->width == Y4M_UNKNOWN || i->height == Y4M_UNKNOWN )
 407           return Y4M_ERR_HEADER;
 408   /* ta da!  done. */
 409   return Y4M_OK;
 410 }
 411
 412
 413
 414 static int y4m_parse_frame_tags(char *s, y4m_frame_info_t *i)
 415 {
 416   char *token, *value av_unused;
 417   char tag;
 418   int err;
 419
 420   /* parse fields */
 421   for (token = strtok(s, Y4M_DELIM);
 422        token != NULL;
 423        token = strtok(NULL, Y4M_DELIM)) {
 424     if (token[0] == '\0') continue;   /* skip empty strings */
 425     tag = token[0];
 426     value = token + 1;
 427     switch (tag) {
 428     case 'X':  /* 'X' meta-tag */
 429       if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
 430       break;
 431     default:
 432       /* possible error on unknown options */
 433       if (_y4mparam_allow_unknown_tags) {
 434         /* unknown tags ok:  store in xtag list and warn... */
 435         if ((err = y4m_xtag_add(&(i->x_tags), token)) != Y4M_OK) return err;
 436         mp_msg(MSGT_DEMUX, MSGL_WARN, "Unknown frame tag encountered:  '%s'\n", token);
 437       } else {
 438         /* unknown tags are *not* ok */
 439         return Y4M_ERR_BADTAG;
 440       }
 441       break;
 442     }
 443   }
 444   /* ta da!  done. */
 445   return Y4M_OK;
 446 }
 447
 448
 449
 450
 451
 452 /*************************************************************************
 453  *
 454  * Read/Write stream header
 455  *
 456  *************************************************************************/
 457
 458
 459 int y4m_read_stream_header(stream_t *s, y4m_stream_info_t *i)
 460 {
 461    char line[Y4M_LINE_MAX];
 462    char *p;
 463    int n;
 464    int err;
 465
 466    /* read the header line */
 467    for (n = 0, p = line; n < Y4M_LINE_MAX; n++, p++) {
 468      if (y4m_read(s, p, 1))
 469        return Y4M_ERR_SYSTEM;
 470      if (*p == '\n') {
 471        *p = '\0';           /* Replace linefeed by end of string */
 472        break;
 473      }
 474    }
 475    if (n >= Y4M_LINE_MAX)
 476       return Y4M_ERR_HEADER;
 477    /* look for keyword in header */
 478    if (strncmp(line, Y4M_MAGIC, strlen(Y4M_MAGIC)))
 479     return Y4M_ERR_MAGIC;
 480    if ((err = y4m_parse_stream_tags(line + strlen(Y4M_MAGIC), i)) != Y4M_OK)
 481      return err;
 482
 483    i->framelength = (i->height * i->width) * 3 / 2;
 484    return Y4M_OK;
 485 }
 486
 487
 488 #if 0
 489 int y4m_write_stream_header(int fd, y4m_stream_info_t *i)
 490 {
 491   char s[Y4M_LINE_MAX+1];
 492   int n;
 493   int err;
 494
 495   y4m_ratio_reduce(&(i->framerate));
 496   y4m_ratio_reduce(&(i->sampleaspect));
 497   n = snprintf(s, sizeof(s), "%s W%d H%d F%d:%d I%s A%d:%d",
 498                Y4M_MAGIC,
 499                i->width,
 500                i->height,
 501                i->framerate.n, i->framerate.d,
 502                (i->interlace == Y4M_ILACE_NONE) ? "p" :
 503                (i->interlace == Y4M_ILACE_TOP_FIRST) ? "t" :
 504                (i->interlace == Y4M_ILACE_BOTTOM_FIRST) ? "b" : "?",
 505                i->sampleaspect.n, i->sampleaspect.d);
 506   if ((n < 0) || (n > Y4M_LINE_MAX)) return Y4M_ERR_HEADER;
 507   if ((err = y4m_snprint_xtags(s + n, sizeof(s) - n - 1, &(i->x_tags)))
 508       != Y4M_OK)
 509     return err;
 510   /* non-zero on error */
 511   return (y4m_write(fd, s, strlen(s)) ? Y4M_ERR_SYSTEM : Y4M_OK);
 512 }
 513 #endif
 514
 515
 516
 517
 518 /*************************************************************************
 519  *
 520  * Read/Write frame header
 521  *
 522  *************************************************************************/
 523
 524 int y4m_read_frame_header(stream_t *s, y4m_frame_info_t *i)
 525 {
 526   char line[Y4M_LINE_MAX];
 527   char *p;
 528   int n;
 529   ssize_t remain;
 530
 531   /* This is more clever than read_stream_header...
 532      Try to read "FRAME\n" all at once, and don't try to parse
 533      if nothing else is there...
 534   */
 535   remain = y4m_read(s, line, sizeof(Y4M_FRAME_MAGIC));
 536   if (remain != 0)
 537   {
 538           /* A clean EOF should end exactly at a frame-boundary */
 539           if( remain == sizeof(Y4M_FRAME_MAGIC) )
 540                   return Y4M_ERR_EOF;
 541           else
 542                   return Y4M_ERR_SYSTEM;
 543   }
 544   if (strncmp(line, Y4M_FRAME_MAGIC, sizeof(Y4M_FRAME_MAGIC)-1))
 545     return Y4M_ERR_MAGIC;
 546   if (line[sizeof(Y4M_FRAME_MAGIC)-1] == '\n')
 547     return Y4M_OK; /* done -- no tags:  that was the end-of-line. */
 548
 549   if (line[sizeof(Y4M_FRAME_MAGIC)-1] != Y4M_DELIM[0]) {
 550     return Y4M_ERR_MAGIC; /* wasn't a space -- what was it? */
 551   }
 552
 553   /* proceed to get the tags... (overwrite the magic) */
 554   for (n = 0, p = line; n < Y4M_LINE_MAX; n++, p++) {
 555     if (y4m_read(s, p, 1))
 556       return Y4M_ERR_SYSTEM;
 557     if (*p == '\n') {
 558       *p = '\0';           /* Replace linefeed by end of string */
 559       break;
 560     }
 561   }
 562   if (n >= Y4M_LINE_MAX) return Y4M_ERR_HEADER;
 563   /* non-zero on error */
 564   return y4m_parse_frame_tags(line, i);
 565 }
 566
 567
 568 #if 0
 569 int y4m_write_frame_header(int fd, y4m_frame_info_t *i)
 570 {
 571   char s[Y4M_LINE_MAX+1];
 572   int n;
 573   int err;
 574
 575   n = snprintf(s, sizeof(s), "%s", Y4M_FRAME_MAGIC);
 576   if ((n < 0) || (n > Y4M_LINE_MAX)) return Y4M_ERR_HEADER;
 577   if ((err = y4m_snprint_xtags(s + n, sizeof(s) - n - 1, &(i->x_tags)))
 578       != Y4M_OK)
 579     return err;
 580   /* non-zero on error */
 581   return (y4m_write(fd, s, strlen(s)) ? Y4M_ERR_SYSTEM : Y4M_OK);
 582 }
 583 #endif
 584
 585
 586
 587 /*************************************************************************
 588  *
 589  * Read/Write entire frame
 590  *
 591  *************************************************************************/
 592
 593 int y4m_read_frame(stream_t *s, y4m_stream_info_t *si,
 594                    y4m_frame_info_t *fi, unsigned char *yuv[3])
 595 {
 596   int err;
 597   int w = si->width;
 598   int h = si->height;
 599
 600   /* Read frame header */
 601   if ((err = y4m_read_frame_header(s, fi)) != Y4M_OK) return err;
 602   /* Read luminance scanlines */
 603   if (y4m_read(s, yuv[0], w*h)) return Y4M_ERR_SYSTEM;
 604   /* Read chrominance scanlines */
 605   if (y4m_read(s, yuv[1], w*h/4)) return Y4M_ERR_SYSTEM;
 606   if (y4m_read(s, yuv[2], w*h/4)) return Y4M_ERR_SYSTEM;
 607
 608   return Y4M_OK;
 609 }
 610
 611
 612
 613 #if 0
 614 int y4m_write_frame(int fd, y4m_stream_info_t *si,
 615                     y4m_frame_info_t *fi, unsigned char *yuv[3])
 616 {
 617   int err;
 618   int w = si->width;
 619   int h = si->height;
 620
 621   /* Write frame header */
 622   if ((err = y4m_write_frame_header(fd, fi)) != Y4M_OK) return err;
 623   /* Write luminance,chrominance scanlines */
 624   if (y4m_write(fd, yuv[0], w*h) ||
 625       y4m_write(fd, yuv[1], w*h/4) ||
 626       y4m_write(fd, yuv[2], w*h/4))
 627     return Y4M_ERR_SYSTEM;
 628   return Y4M_OK;
 629 }
 630 #endif
 631
 632
 633 /*************************************************************************
 634  *
 635  * Read/Write entire frame, (de)interleaved (to)from two separate fields
 636  *
 637  *************************************************************************/
 638
 639 #if 0
 640 int y4m_read_fields(int fd, y4m_stream_info_t *si, y4m_frame_info_t *fi,
 641                     unsigned char *upper_field[3],
 642                     unsigned char *lower_field[3])
 643 {
 644   int i, y, err;
 645   int width = si->width;
 646   int height = si->height;
 647
 648   /* Read frame header */
 649   if ((err = y4m_read_frame_header(fd, fi)) != Y4M_OK) return err;
 650   /* Read Y', Cb, and Cr planes */
 651   for (i = 0; i < 3; i++) {
 652     unsigned char *srctop = upper_field[i];
 653     unsigned char *srcbot = lower_field[i];
 654     /* alternately write one line from each */
 655     for (y = 0; y < height; y += 2) {
 656       if (y4m_read(fd, srctop, width)) return Y4M_ERR_SYSTEM;
 657       srctop += width;
 658       if (y4m_read(fd, srcbot, width)) return Y4M_ERR_SYSTEM;
 659       srcbot += width;
 660     }
 661     /* for chroma, width/height are half as big */
 662     if (i == 0) {
 663       width /= 2;
 664       height /= 2;
 665     }
 666   }
 667   return Y4M_OK;
 668 }
 669
 670
 671
 672 int y4m_write_fields(int fd, y4m_stream_info_t *si, y4m_frame_info_t *fi,
 673                      unsigned char *upper_field[3],
 674                      unsigned char *lower_field[3])
 675 {
 676   int i, y, err;
 677   int width = si->width;
 678   int height = si->height;
 679
 680   /* Write frame header */
 681   if ((err = y4m_write_frame_header(fd, fi)) != Y4M_OK) return err;
 682   /* Write Y', Cb, and Cr planes */
 683   for (i = 0; i < 3; i++) {
 684     unsigned char *srctop = upper_field[i];
 685     unsigned char *srcbot = lower_field[i];
 686     /* alternately write one line from each */
 687     for (y = 0; y < height; y += 2) {
 688       if (y4m_write(fd, srctop, width)) return Y4M_ERR_SYSTEM;
 689       srctop += width;
 690       if (y4m_write(fd, srcbot, width)) return Y4M_ERR_SYSTEM;
 691       srcbot += width;
 692     }
 693     /* for chroma, width/height are half as big */
 694     if (i == 0) {
 695       width /= 2;
 696       height /= 2;
 697     }
 698   }
 699   return Y4M_OK;
 700 }
 701 #endif
 702
 703
 704 /*************************************************************************
 705  *
 706  * Handy logging of stream info
 707  *
 708  *************************************************************************/
 709
 710 void y4m_log_stream_info(const char *prefix, y4m_stream_info_t *i)
 711 {
 712   char s[256];
 713
 714   snprintf(s, sizeof(s), "  frame size:  ");
 715   if (i->width == Y4M_UNKNOWN)
 716     snprintf(s+strlen(s), sizeof(s)-strlen(s), "(?)x");
 717   else
 718     snprintf(s+strlen(s), sizeof(s)-strlen(s), "%dx", i->width);
 719   if (i->height == Y4M_UNKNOWN)
 720     snprintf(s+strlen(s), sizeof(s)-strlen(s), "(?) pixels ");
 721   else
 722     snprintf(s+strlen(s), sizeof(s)-strlen(s), "%d pixels ", i->height);
 723   if (i->framelength == Y4M_UNKNOWN)
 724     snprintf(s+strlen(s), sizeof(s)-strlen(s), "(? bytes)");
 725   else
 726     snprintf(s+strlen(s), sizeof(s)-strlen(s), "(%d bytes)", i->framelength);
 727   mp_msg(MSGT_DEMUX, MSGL_V, "%s%s\n", prefix, s);
 728   if ((i->framerate.n == 0) && (i->framerate.d == 0))
 729     mp_msg(MSGT_DEMUX, MSGL_V, "%s  frame rate:  ??? fps\n", prefix);
 730   else
 731     mp_msg(MSGT_DEMUX, MSGL_V, "%s  frame rate:  %d/%d fps (~%f)\n", prefix,
 732               i->framerate.n, i->framerate.d,
 733               (double) i->framerate.n / (double) i->framerate.d);
 734   mp_msg(MSGT_DEMUX, MSGL_V, "%s   interlace:  %s\n", prefix,
 735           (i->interlace == Y4M_ILACE_NONE) ? "none/progressive" :
 736           (i->interlace == Y4M_ILACE_TOP_FIRST) ? "top-field-first" :
 737           (i->interlace == Y4M_ILACE_BOTTOM_FIRST) ? "bottom-field-first" :
 738           "anyone's guess");
 739   if ((i->sampleaspect.n == 0) && (i->sampleaspect.d == 0))
 740     mp_msg(MSGT_DEMUX, MSGL_V, "%ssample aspect ratio:  ?:?\n", prefix);
 741   else
 742     mp_msg(MSGT_DEMUX, MSGL_V, "%ssample aspect ratio:  %d:%d\n", prefix,
 743               i->sampleaspect.n, i->sampleaspect.d);
 744 }
 745
 746
 747 /*************************************************************************
 748  *
 749  * Convert error code to string
 750  *
 751  *************************************************************************/
 752
 753 const char *y4m_strerr(int err)
 754 {
 755   switch (err) {
 756   case Y4M_OK:          return "no error";
 757   case Y4M_ERR_RANGE:   return "parameter out of range";
 758   case Y4M_ERR_SYSTEM:  return "stream ended unexpectedly (failed read/write)";
 759   case Y4M_ERR_HEADER:  return "bad stream or frame header";
 760   case Y4M_ERR_BADTAG:  return "unknown header tag";
 761   case Y4M_ERR_MAGIC:   return "bad header magic";
 762   case Y4M_ERR_XXTAGS:  return "too many xtags";
 763   case Y4M_ERR_EOF:     return "end-of-file";
 764   default:
 765     return "unknown error code";
 766   }
 767 }