File Content: sample5.c /* * sample5.c * Copyright (C) 2003 Regis Duchesne <hpreg@zoy.org> * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org> * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca> * Copyright (C) 2006 Sam Hocevar <sam@zoy.org> * * This file is part of mpeg2dec, a free MPEG-2 video stream decoder. * See http://libmpeg2.sourceforge.net/ for updates. * * mpeg2dec 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. * * mpeg2dec 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 * * This program reads a MPEG-2 stream, and saves each of its frames as * an image file using the PGM format (black and white). * * It demonstrates how to use the following features of libmpeg2: * - Output buffers use the YUV 4:2:0 planar format. * - Output buffers must be 16-byte aligned. * - Output buffers are allocated and managed by the caller. */ #include <stdio.h> #include <stdlib.h> #include <inttypes.h> #include "mpeg2.h" static void save_pgm (int width, int height, int chroma_width, int chroma_height, uint8_t * const * buf, int num) { char filename[100]; FILE * pgmfile; int i; static uint8_t black[16384] = { 0 }; sprintf (filename, "%d.pgm", num); pgmfile = fopen (filename, "wb"); if (!pgmfile) { fprintf (stderr, "Could not open file \"%s\".\n", filename); exit (1); } fprintf (pgmfile, "P5\n%d %d\n255\n", 2 * chroma_width, height + chroma_height); for (i = 0; i < height; i++) { fwrite (buf[0] + i * width, width, 1, pgmfile); fwrite (black, 2 * chroma_width - width, 1, pgmfile); } for (i = 0; i < chroma_height; i++) { fwrite (buf[1] + i * chroma_width, chroma_width, 1, pgmfile); fwrite (buf[2] + i * chroma_width, chroma_width, 1, pgmfile); } fclose (pgmfile); } static struct fbuf_s { uint8_t * mbuf[3]; uint8_t * yuv[3]; int used; } fbuf[3]; static struct fbuf_s * get_fbuf (void) { int i; for (i = 0; i < 3; i++) if (!fbuf[i].used) { fbuf[i].used = 1; return fbuf + i; } fprintf (stderr, "Could not find a free fbuf.\n"); exit (1); } static void sample5 (FILE * mpgfile) { #define BUFFER_SIZE 4096 #define ALIGN_16(p) ((void *)(((uintptr_t)(p) + 15) & ~((uintptr_t)15))) uint8_t buffer[BUFFER_SIZE]; mpeg2dec_t * decoder; const mpeg2_info_t * info; const mpeg2_sequence_t * sequence; mpeg2_state_t state; size_t size; int framenum = 0; int i, j; struct fbuf_s * current_fbuf; decoder = mpeg2_init (); if (decoder == NULL) { fprintf (stderr, "Could not allocate a decoder object.\n"); exit (1); } info = mpeg2_info (decoder); size = (size_t)-1; do { state = mpeg2_parse (decoder); sequence = info->sequence; switch (state) { case STATE_BUFFER: size = fread (buffer, 1, BUFFER_SIZE, mpgfile); mpeg2_buffer (decoder, buffer, buffer + size); break; case STATE_SEQUENCE: mpeg2_custom_fbuf (decoder, 1); for (i = 0; i < 3; i++) { fbuf[i].mbuf[0] = (uint8_t *) malloc (sequence->width * sequence->height + 15); fbuf[i].mbuf[1] = (uint8_t *) malloc (sequence->chroma_width * sequence->chroma_height + 15); fbuf[i].mbuf[2] = (uint8_t *) malloc (sequence->chroma_width * sequence->chroma_height + 15); if (!fbuf[i].mbuf[0] || !fbuf[i].mbuf[1] || !fbuf[i].mbuf[2]) { fprintf (stderr, "Could not allocate an output buffer.\n"); exit (1); } for (j = 0; j < 3; j++) fbuf[i].yuv[j] = ALIGN_16 (fbuf[i].mbuf[j]); fbuf[i].used = 0; } for (i = 0; i < 2; i++) { current_fbuf = get_fbuf (); mpeg2_set_buf (decoder, current_fbuf->yuv, current_fbuf); } break; case STATE_PICTURE: current_fbuf = get_fbuf (); mpeg2_set_buf (decoder, current_fbuf->yuv, current_fbuf); break; case STATE_SLICE: case STATE_END: case STATE_INVALID_END: if (info->display_fbuf) save_pgm (sequence->width, sequence->height, sequence->chroma_width, sequence->chroma_height, info->display_fbuf->buf, framenum++); if (info->discard_fbuf) ((struct fbuf_s *)info->discard_fbuf->id)->used = 0; if (state != STATE_SLICE) for (i = 0; i < 3; i++) for (j = 0; j < 3; j++) free (fbuf[i].mbuf[j]); break; default: break; } } while (size); mpeg2_close (decoder); } int main (int argc, char ** argv) { FILE * mpgfile; if (argc > 1) { mpgfile = fopen (argv[1], "rb"); if (!mpgfile) { fprintf (stderr, "Could not open file \"%s\".\n", argv[1]); exit (1); } } else mpgfile = stdin; sample5 (mpgfile); return 0; } Submit