libmpcodecs/vf_framestep.c

   1 /*
   2  * filter to ouput only 1 every n frame, or only the I (key)frame
   3  *
   4  * The parameters are:
   5  *
   6  *    [I] | [i]num
   7  *
   8  * if you call the filter with I (uppercase) as the parameter
   9  *    ... -vf framestep=I ...
  10  * then ONLY the keyframes are outputted.
  11  * For DVD it means, generally, one every 15 frames (IBBPBBPBBPBBPBB), for avi it means
  12  * every scene change or every keyint value (see -lavcopts).
  13  *
  14  * if you call the filter with the i (lowercase)
  15  *    ... -vf framestep=i ...
  16  * then a I! followed by a cr is printed when a key frame (eg Intra frame) is
  17  * found, leaving the current line of mplayer, where you got the time, in
  18  * seconds, and frame of the key. Use this information to split the AVI.
  19  *
  20  * After the i or alone you can put a positive number and only one frame every
  21  * x (the number you set) is passed on the filter chain, limiting the output
  22  * of the frame.
  23  *
  24  * Example
  25  *    ... -vf framestep=i20 ...
  26  * Dump one every 20 frames, printing on the console when a I-Frame is encounter.
  27  *
  28  *    ... -vf framestep=25
  29  * Dump one every 25 frames.
  30  *
  31  * If you call the filter without parameter it does nothing (except using memory
  32  * and resource of your system,. of course).
  33  *
  34  * This filter doesn' t work like the option -sstep seconds.
  35  *
  36  * The -sstep seek to the new position, without decoding all frames but,
  37  * expecially on avi file coded whith mpeg4 (lavc or xvid or divx), the
  38  * seek is not always too much precise.
  39  *
  40  * This filter simply discard the unwanted frames, so you are very precise in
  41  * counting the frame but sometime you use a lot of CPU for nothing.
  42  *
  43  * As usual it depends on what you're doing.
  44  *
  45  * copyright (c) 2003 Daniele Forghieri ( guru@digitalfantasy.it )
  46  *
  47  * This file is part of MPlayer.
  48  *
  49  * MPlayer is free software; you can redistribute it and/or modify
  50  * it under the terms of the GNU General Public License as published by
  51  * the Free Software Foundation; either version 2 of the License, or
  52  * (at your option) any later version.
  53  *
  54  * MPlayer is distributed in the hope that it will be useful,
  55  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  56  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  57  * GNU General Public License for more details.
  58  *
  59  * You should have received a copy of the GNU General Public License along
  60  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  61  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  62  */
  63
  64 #include <stdio.h>
  65 #include <stdlib.h>
  66 #include <string.h>
  67
  68 #include "config.h"
  69 #include "mp_msg.h"
  70 #include "cpudetect.h"
  71
  72 #include "img_format.h"
  73 #include "mp_image.h"
  74 #include "vf.h"
  75
  76 /* Uncomment if you want to print some info on the format */
  77 // #define DUMP_FORMAT_DATA
  78
  79 /* Private data */
  80 struct vf_priv_s {
  81     /* Current frame */
  82     int  frame_cur;
  83     /* Frame output step, 0 = all */
  84     int  frame_step;
  85     /* Only I-Frame (2), print on I-Frame (1) */
  86     int  dump_iframe;
  87 };
  88
  89 /* Filter handler */
  90 static int put_image(struct vf_instance *vf, mp_image_t *mpi, double pts)
  91 {
  92     mp_image_t        *dmpi;
  93     struct vf_priv_s  *priv;
  94     int               skip;
  95
  96     priv = vf->priv;
  97
  98     /* Print the 'I' if is a intra frame. The \n advance the current line so you got the
  99      * current file time (in second) and the frame number on the console ;-)
 100      */
 101     if (priv->dump_iframe) {
 102         if (mpi->pict_type == 1) {
 103             mp_msg(MSGT_VFILTER, MSGL_INFO, "I!\n");
 104         }
 105     }
 106
 107     /* decide if frame must be shown */
 108     if (priv->dump_iframe == 2) {
 109         /* Only key frame */
 110         skip = mpi->pict_type == 1 ? 0 : 1;
 111     }
 112     else {
 113         /* Only 1 every frame_step */
 114         skip = 0;
 115         if ((priv->frame_step != 0) && ((priv->frame_cur % priv->frame_step) != 0)) {
 116             skip = 1;
 117         }
 118     }
 119     /* Increment current frame */
 120     ++priv->frame_cur;
 121
 122     if (skip == 0) {
 123         /* Get image, export type (we don't modify tghe image) */
 124         dmpi=vf_get_image(vf->next, mpi->imgfmt,
 125                       MP_IMGTYPE_EXPORT, 0,
 126                       mpi->w, mpi->h);
 127         /* Copy only the pointer ( MP_IMGTYPE_EXPORT ! ) */
 128         dmpi->planes[0] = mpi->planes[0];
 129         dmpi->planes[1] = mpi->planes[1];
 130         dmpi->planes[2] = mpi->planes[2];
 131
 132         dmpi->stride[0] = mpi->stride[0];
 133         dmpi->stride[1] = mpi->stride[1];
 134         dmpi->stride[2] = mpi->stride[2];
 135
 136         dmpi->width     = mpi->width;
 137         dmpi->height    = mpi->height;
 138
 139         /* Chain to next filter / output ... */
 140         return vf_next_put_image(vf, dmpi, pts);
 141     }
 142
 143     /* Skip the frame */
 144     return 0;
 145 }
 146
 147 static void uninit(struct vf_instance *vf)
 148 {
 149     /* Free private data */
 150     free(vf->priv);
 151 }
 152
 153 /* Main entry funct for the filter */
 154 static int vf_open(vf_instance_t *vf, char *args)
 155 {
 156         struct vf_priv_s *p;
 157
 158         vf->put_image = put_image;
 159         vf->uninit = uninit;
 160         vf->default_reqs = VFCAP_ACCEPT_STRIDE;
 161         vf->priv = p = calloc(1, sizeof(struct vf_priv_s));
 162         if (p == NULL) {
 163             return 0;
 164         }
 165
 166         if (args != NULL) {
 167 #ifdef DUMP_FORMAT_DATA
 168             if (*args == 'd') {
 169                 p->dump_iframe = 3;
 170             }
 171             else
 172 #endif
 173             if (*args == 'I') {
 174                 /* Dump only KEY (ie INTRA) frame */
 175                 p->dump_iframe = 2;
 176             }
 177             else {
 178                 if (*args == 'i') {
 179                     /* Print a 'I!' when a i-frame is encounter */
 180                     p->dump_iframe = 1;
 181                     ++args;
 182                 }
 183
 184                 if (*args != '\0') {
 185                     p->frame_step = atoi(args);
 186                     if (p->frame_step <= 0) {
 187                         mp_tmsg(MSGT_VFILTER, MSGL_WARN, "[VF_FRAMESTEP] Error parsing argument.\n");
 188                         return 0;
 189                     }
 190                 }
 191             }
 192         }
 193         return 1;
 194 }
 195
 196 const vf_info_t vf_info_framestep = {
 197     "Dump one every n / key frames",
 198     "framestep",
 199     "Daniele Forghieri",
 200     "",
 201     vf_open,
 202     NULL
 203 };