libmpcodecs/vf_framestep.c

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