yuv4mpeg.c

Motion JPEG编解码器源代码

/*
 *  yuv4mpeg.c:  Functions for reading and writing "new" YUV4MPEG streams
 *
 *  Copyright (C) 2001 Matthew J. Marjanovic <[e-mail]>
 *
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version 2
 *  of the License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 *
 */

#include <config.h>

#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#define INTERNAL_Y4M_LIBCODE_STUFF_QPX
#include "yuv4mpeg.h"
#include "yuv4mpeg_intern.h"
#include "mjpeg_logging.h"


static int _y4mparam_allow_unknown_tags = 1;  /* default is forgiveness */
static int _y4mparam_feature_level = 0;       /* default is ol YUV4MPEG2 */

static void *(*_y4m_alloc)(size_t bytes) = malloc;
static void (*_y4m_free)(void *ptr) = free;



int y4m_allow_unknown_tags(int yn)
{
  int old = _y4mparam_allow_unknown_tags;
  if (yn >= 0)
    _y4mparam_allow_unknown_tags = (yn) ? 1 : 0;
  return old;
}


int y4m_accept_extensions(int level)
{
  int old = _y4mparam_feature_level;
  if (level >= 0)
    _y4mparam_feature_level = level;
  return old;
}



/*************************************************************************
 *
 * Convenience functions for fd read/write
 *
 *   - guaranteed to transfer entire payload (or fail)
 *   - returns:
 *               0 on complete success
 *               +(# of remaining bytes) on eof (for y4m_read)
 *               -(# of rem. bytes) on error (and ERRNO should be set)
 *     
 *************************************************************************/


ssize_t y4m_read(int fd, void *buf, size_t len)
{
   ssize_t n;
   uint8_t *ptr = (uint8_t *)buf;

   while (len > 0) {
     n = read(fd, ptr, len);
     if (n <= 0) {
       /* return amount left to read */
       if (n == 0)
	 return len;  /* n == 0 --> eof */
       else
	 return -len; /* n < 0 --> error */
     }
     ptr += n;
     len -= n;
   }
   return 0;
}


ssize_t y4m_write(int fd, const void *buf, size_t len)
{
   ssize_t n;
   const uint8_t *ptr = (const uint8_t *)buf;

   while (len > 0) {
     n = write(fd, ptr, len);
     if (n <= 0) return -len;  /* return amount left to write */
     ptr += n;
     len -= n;
   }
   return 0;
}




/*************************************************************************
 *
 * "Extra tags" handling
 *
 *************************************************************************/


static char *y4m_new_xtag(void)
{
  return _y4m_alloc(Y4M_MAX_XTAG_SIZE * sizeof(char));
}


void y4m_init_xtag_list(y4m_xtag_list_t *xtags)
{
  int i;
  xtags->count = 0;
  for (i = 0; i < Y4M_MAX_XTAGS; i++) {
    xtags->tags[i] = NULL;
  }
}


void y4m_fini_xtag_list(y4m_xtag_list_t *xtags)
{
  int i;
  for (i = 0; i < Y4M_MAX_XTAGS; i++) {
    if (xtags->tags[i] != NULL) {
      _y4m_free(xtags->tags[i]);
      xtags->tags[i] = NULL;
    }
  }
  xtags->count = 0;
}


void y4m_copy_xtag_list(y4m_xtag_list_t *dest, const y4m_xtag_list_t *src)
{
  int i;
  for (i = 0; i < src->count; i++) {
    if (dest->tags[i] == NULL) 
      dest->tags[i] = y4m_new_xtag();
    strncpy(dest->tags[i], src->tags[i], Y4M_MAX_XTAG_SIZE);
  }
  dest->count = src->count;
}



static int y4m_snprint_xtags(char *s, int maxn, const y4m_xtag_list_t *xtags)
{
  int i, room;
  
  for (i = 0, room = maxn - 1; i < xtags->count; i++) {
    int n = snprintf(s, room + 1, " %s", xtags->tags[i]);
    if ((n < 0) || (n > room)) return Y4M_ERR_HEADER;
    s += n;
    room -= n;
  }
  s[0] = '\n';  /* finish off header with newline */
  s[1] = '\0';  /* ...and end-of-string           */
  return Y4M_OK;
}


int y4m_xtag_count(const y4m_xtag_list_t *xtags)
{
  return xtags->count;
}


const char *y4m_xtag_get(const y4m_xtag_list_t *xtags, int n)
{
  if (n >= xtags->count)
    return NULL;
  else
    return xtags->tags[n];
}


int y4m_xtag_add(y4m_xtag_list_t *xtags, const char *tag)
{
  if (xtags->count >= Y4M_MAX_XTAGS) return Y4M_ERR_XXTAGS;
  if (xtags->tags[xtags->count] == NULL) 
    xtags->tags[xtags->count] = y4m_new_xtag();
  strncpy(xtags->tags[xtags->count], tag, Y4M_MAX_XTAG_SIZE);
  (xtags->count)++;
  return Y4M_OK;
}


int y4m_xtag_remove(y4m_xtag_list_t *xtags, int n)
{
  int i;
  char *q;

  if ((n < 0) || (n >= xtags->count)) return Y4M_ERR_RANGE;
  q = xtags->tags[n];
  for (i = n; i < (xtags->count - 1); i++)
    xtags->tags[i] = xtags->tags[i+1];
  xtags->tags[i] = q;
  (xtags->count)--;
  return Y4M_OK;
}


int y4m_xtag_clearlist(y4m_xtag_list_t *xtags)
{
  xtags->count = 0;
  return Y4M_OK;
}


int y4m_xtag_addlist(y4m_xtag_list_t *dest, const y4m_xtag_list_t *src)
{
  int i, j;

  if ((dest->count + src->count) > Y4M_MAX_XTAGS) return Y4M_ERR_XXTAGS;
  for (i = dest->count, j = 0;
       j < src->count;
       i++, j++) {
    if (dest->tags[i] == NULL) 
      dest->tags[i] = y4m_new_xtag();
    strncpy(dest->tags[i], src->tags[i], Y4M_MAX_XTAG_SIZE);
  }
  dest->count += src->count;
  return Y4M_OK;
}  


/*************************************************************************
 *
 * Creators/destructors for y4m_*_info_t structures
 *
 *************************************************************************/


void y4m_init_stream_info(y4m_stream_info_t *info)
{
  if (info == NULL) return;
  /* init substructures */
  y4m_init_xtag_list(&(info->x_tags));
  /* set defaults */
  y4m_clear_stream_info(info);
}


void y4m_clear_stream_info(y4m_stream_info_t *info)
{
  if (info == NULL) return;
  /* clear/initialize info */
  info->width = Y4M_UNKNOWN;
  info->height = Y4M_UNKNOWN;
  info->interlace = Y4M_UNKNOWN;
  info->framerate = y4m_fps_UNKNOWN;
  info->sampleaspect = y4m_sar_UNKNOWN;
  if (_y4mparam_feature_level < 1) {
    info->chroma = Y4M_CHROMA_420JPEG;
  } else {
    info->chroma = Y4M_UNKNOWN;
  }
  y4m_xtag_clearlist(&(info->x_tags));
}


void y4m_copy_stream_info(y4m_stream_info_t *dest,
			  const y4m_stream_info_t *src)
{
  if ((dest == NULL) || (src == NULL)) return;
  /* copy info */
  dest->width = src->width;
  dest->height = src->height;
  dest->interlace = src->interlace;
  dest->framerate = src->framerate;
  dest->sampleaspect = src->sampleaspect;
  dest->chroma = src->chroma;
  y4m_copy_xtag_list(&(dest->x_tags), &(src->x_tags));
}


void y4m_fini_stream_info(y4m_stream_info_t *info)
{
  if (info == NULL) return;
  y4m_fini_xtag_list(&(info->x_tags));
}


void y4m_si_set_width(y4m_stream_info_t *si, int width)
{
  si->width = width;
}

int y4m_si_get_width(const y4m_stream_info_t *si)
{ return si->width; }

void y4m_si_set_height(y4m_stream_info_t *si, int height)
{
  si->height = height; 
}

int y4m_si_get_height(const y4m_stream_info_t *si)
{ return si->height; }

void y4m_si_set_interlace(y4m_stream_info_t *si, int interlace)
{ si->interlace = interlace; }

int y4m_si_get_interlace(const y4m_stream_info_t *si)
{ return si->interlace; }

void y4m_si_set_framerate(y4m_stream_info_t *si, y4m_ratio_t framerate)
{ si->framerate = framerate; }

y4m_ratio_t y4m_si_get_framerate(const y4m_stream_info_t *si)
{ return si->framerate; }

void y4m_si_set_sampleaspect(y4m_stream_info_t *si, y4m_ratio_t sar)
{ si->sampleaspect = sar; }

y4m_ratio_t y4m_si_get_sampleaspect(const y4m_stream_info_t *si)
{ return si->sampleaspect; }

void y4m_si_set_chroma(y4m_stream_info_t *si, int chroma_mode)
{ si->chroma = chroma_mode; }

int y4m_si_get_chroma(const y4m_stream_info_t *si)
{ return si->chroma; }


int y4m_si_get_plane_count(const y4m_stream_info_t *si)
{
  switch (si->chroma) {
  case Y4M_CHROMA_420JPEG:
  case Y4M_CHROMA_420MPEG2:
  case Y4M_CHROMA_420PALDV:
  case Y4M_CHROMA_444:
  case Y4M_CHROMA_422:
  case Y4M_CHROMA_411:
    return 3;
  case Y4M_CHROMA_MONO:
    return 1;
  case Y4M_CHROMA_444ALPHA:
    return 4;
  default:
    return Y4M_UNKNOWN;
  }
}

int y4m_si_get_plane_width(const y4m_stream_info_t *si, int plane)
{
  switch (plane) {
  case 0:
    return (si->width);
  case 1:
  case 2:
    switch (si->chroma) {
    case Y4M_CHROMA_420JPEG: 
    case Y4M_CHROMA_420MPEG2:
    case Y4M_CHROMA_420PALDV:
      return (si->width) / 2;
    case Y4M_CHROMA_444:
    case Y4M_CHROMA_444ALPHA:
      return (si->width);
    case Y4M_CHROMA_422:
      return (si->width) / 2;
    case Y4M_CHROMA_411:
      return (si->width) / 4;
    default:
      return Y4M_UNKNOWN;
    }
  case 3:
    switch (si->chroma) {
    case Y4M_CHROMA_444ALPHA:
      return (si->width);
    default:
      return Y4M_UNKNOWN;
    }
  default:
    return Y4M_UNKNOWN;
  }
}

int y4m_si_get_plane_height(const y4m_stream_info_t *si, int plane)
{
  switch (plane) {
  case 0:
    return (si->height);
  case 1:
  case 2:
    switch (si->chroma) {
    case Y4M_CHROMA_420JPEG: 
    case Y4M_CHROMA_420MPEG2:
    case Y4M_CHROMA_420PALDV:
      return (si->height) / 2;
    case Y4M_CHROMA_444:
    case Y4M_CHROMA_444ALPHA:
    case Y4M_CHROMA_422:
    case Y4M_CHROMA_411:
      return (si->height);
    default:
      return Y4M_UNKNOWN;
    }
  case 3:
    switch (si->chroma) {
    case Y4M_CHROMA_444ALPHA:
      return (si->height);
    default:
      return Y4M_UNKNOWN;
    }
  default:
    return Y4M_UNKNOWN;
  }
}

int y4m_si_get_plane_length(const y4m_stream_info_t *si, int plane)
{
  int w = y4m_si_get_plane_width(si, plane);
  int h = y4m_si_get_plane_height(si, plane);
  if ((w != Y4M_UNKNOWN) && (h != Y4M_UNKNOWN))
    return (w * h);
  else
    return Y4M_UNKNOWN;
}

int y4m_si_get_framelength(const y4m_stream_info_t *si)
{
  int total = 0;
  int planes = y4m_si_get_plane_count(si);
  int p;
  for (p = 0; p < planes; p++) {
    int plen = y4m_si_get_plane_length(si, p);
    if (plen == Y4M_UNKNOWN) return Y4M_UNKNOWN;
    total += plen;
  }
  return total;
}