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Diffstat (limited to 'doc/sample5.c')
| -rw-r--r-- | doc/sample5.c | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/doc/sample5.c b/doc/sample5.c new file mode 100644 index 0000000..b20e776 --- /dev/null +++ b/doc/sample5.c @@ -0,0 +1,181 @@ +/* + * 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; +} |