/*

Will Simons

*/

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <libpq-fe.h>

#include <sys/stat.h>

#include <sys/types.h>

#define READ_BUF_LENGTH 1024

#define MAX_DB_STATEMENT_BUFFER_LENGTH 5000

/*

Change these variables to match your database.

*/

#define DBNAME "cs161"

#define HOST "localhost"

#define PORT "5432"

#define USER "postgres"

#define PASSWORD "password"

void clear_buffer(char *buf);

void pipe_to_buffer(FILE *pipe, char *buf, char *cmmd, char const *video_path);

void extract_meta(char const *video_path, int *width, int *height, int *fcount, float *fps);

void extract_stills(char const *video_path, char *dir, float fps);

char *insert_video_meta(char const *name, int width, int height, int fcount, float fps);

int main(int argc, char const *argv[])

{

//Initialize variables

int width, height, fcount;

float fps;

/*

Check if video file location was passed in.

*/

if(argc != 2) {

printf("Program accepts 2 args. ./%s <path/to/video/file> \n", argv[0]);

return 1;

}

//help

if (strcmp(argv[0], "-h") == 0)

{

printf("Extracts still images from video file to directory named by unique id given to video in database.");

printf("\n%s <path/to/video/file>\n", argv[0]);

return 1;

}

//Extracts meta from video into width, height, f(rame)count, fps variables

extract_meta(argv[1], &width, &height, &fcount, &fps);

//Insert Video Metadata into database.

char *unique_id = insert_video_meta(argv[1], width, height, fcount, fps);

//Extract still images from video into directory named by unique_id

char dir[1024] = "images/";

strcat(dir, unique_id);

extract_stills(argv[1], dir, fps);

return 0;

}

/*

Inserts video metadata into database.

Connects to database

*/

char *insert_video_meta(char const *name, int width, int height, int fcount, float fps) {

char db_statement[MAX_DB_STATEMENT_BUFFER_LENGTH];

char conninfo[MAX_DB_STATEMENT_BUFFER_LENGTH];

PGconn *conn;

PGresult *res;

int num_rows;

int i, j;

char *unique_id;

// sprintf(unique_id, "-1");

snprintf(&conninfo[0], MAX_DB_STATEMENT_BUFFER_LENGTH,"dbname = '%s' host = '%s' port = '%s' user = '%s' password = '%s'",

DBNAME, HOST, PORT, USER, PASSWORD);

conn = PQconnectdb(conninfo);

if(PQstatus(conn) != CONNECTION_OK)

{

printf("Connetion to database failed: %s\n", PQerrorMessage(conn));

PQfinish(conn);

exit(EXIT_FAILURE);

}

snprintf(&db_statement[0], MAX_DB_STATEMENT_BUFFER_LENGTH, "INSERT INTO video_meta (name, num_frames, x_resolution, y_resolution, fps) VALUES ('%s', %d, %d, %d, %f) RETURNING video_id;",

name, fcount, width, height, fps);

res = PQexec(conn, &db_statement[0]);

switch (PQresultStatus(res)) {

case PGRES_COMMAND_OK:

printf("Executed command, no return.\n");

break;

case PGRES_TUPLES_OK:

num_rows = PQntuples(res);

unique_id = PQgetvalue(res, 0, 0);

break;

default:

printf("Something went wrong.\n");

break;

}

PQfinish(conn);

return unique_id;

}

/*

Clears char* buffer.

*/

void clear_buffer(char *buf)

{

int toClear = strlen(buf);

memset(&buf[0], 0, sizeof(buf));

}

/*

Executes cmmd through popen and returns output to buffer.

*/

void pipe_to_buffer(FILE *pipe, char *buf, char *cmmd, char const *vid)

{

strcat(cmmd, vid);

if ((pipe = popen(cmmd, "r")) == NULL) {

perror("popen");

exit(1);

}

fgets(buf, 80, pipe);

pclose(pipe);

}

/*

Extract Meta information from video using ffprobe.

*/

void extract_meta(char const *video_path, int *width, int *height, int *fcount, float *fps)

{

FILE *pipe_fp;

char readbuf[80]; //todo: magic number, not good

char fcount_probe_cmmd[1024] = "ffprobe -v error -count_frames -select_streams v:0 -show_entries stream=nb_read_frames -of default=nokey=1:noprint_wrappers=1 ";

char fps_probe_cmmd[1024] = "ffprobe -v error -select_streams v:0 -show_entries stream=avg_frame_rate -of default=noprint_wrappers=1:nokey=1 ";

char y_probe_cmmd[1024] = "ffprobe -v error -of flat=s=_ -select_streams v:0 -show_entries stream=height ";

char x_probe_cmmd[1024] = "ffprobe -v error -of flat=s=_ -select_streams v:0 -show_entries stream=width ";

/*

Extract frame count information from video.

*/

pipe_to_buffer(pipe_fp, readbuf, fcount_probe_cmmd, video_path);

if(sscanf(readbuf, "%d", fcount) != 1) {

// printf("Frame Count could not be read.\n");

}

printf("Frame Count: %d\n", *fcount);

clear_buffer(readbuf);

/*

Extract fps information from video.

*/

pipe_to_buffer(pipe_fp, readbuf, fps_probe_cmmd, video_path);

int _n, _d; //must extract

if(sscanf(readbuf, "%d/%d", &_n, &_d) != 1) {

// printf("FPScould not be read.\n");

}

float _f = ((float) _n / (float) _d);

memcpy(fps, &_f, sizeof(float));

printf("FPS (%d/%d) : %f\n", _n, _d, *fps);

clear_buffer(readbuf);

/*

Extract height information from video.

*/

pipe_to_buffer(pipe_fp, readbuf, y_probe_cmmd, video_path);

if(sscanf(readbuf, "streams_stream_0_height=%d", height) != 1) {

// printf("FPScould not be read.\n");

}

printf("Height: %d\n", *height);

clear_buffer(readbuf);

/*

Extract width information from video.

*/

pipe_to_buffer(pipe_fp, readbuf, x_probe_cmmd, video_path);

if(sscanf(readbuf, "streams_stream_0_width=%d", width) != 1) {

// printf("FPScould not be read.\n");

}

printf("Width: %d\n", *width);

clear_buffer(readbuf);

}

/*

Calls ffmpeg to extract stills from video.

*/

void extract_stills(char const *video_path, char *dir, float fps) {

FILE *pipe_fp;

struct stat st = {0};

//check if directory exists already

if(stat(dir, &st) == -1) {

mkdir(dir, 0700);

printf("Created directory %s\n", dir);

} else {

printf("Directory %s already exists, could not create directory.\n", dir);

pclose(pipe_fp);

exit(1);

}

//constructing this `ffmpeg -i IMG_2461.MOV -vf fps=29.982466 testout/out\%d.png"`

char extract_frames_cmmd[2048] = "ffmpeg -i ";

//construct ffmpeg command

strcat(extract_frames_cmmd, video_path);

strcat(extract_frames_cmmd, " -vf fps=");

//convert fps (float) to string

char str_fps[100];

sprintf(str_fps, "%f ", fps);

strcat(extract_frames_cmmd, str_fps);

strcat(extract_frames_cmmd, dir);

strcat(extract_frames_cmmd, "/0.\%d.png");

printf("%s\n", extract_frames_cmmd);

//execute command then close pipe

if ((pipe_fp = popen(extract_frames_cmmd, "r")) == NULL) {

perror("popen");

exit(1);

}

pclose(pipe_fp);

}