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Basic Player Application using GPAC
Romain Bouqueau edited this page Mar 5, 2024
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This example shows a basic GPAC player application. It takes an URL as input and outputs it in a terminal.
Below is the code for the main application. Refer to attached file for full program.
int main (int argc, char **argv)
{
char c;
const char *str;
u32 i;
char *url_arg, *the_cfg;
strcpy(the_url, "."); // use current directory by default
/** Initialisations
* - GF_User object
* - url
* - configuration file **/
memset(&user, 0, sizeof(GF_User));
url_arg = the_cfg = NULL;
/** Load configuration file
* - load a configuration file (.gpacrc) if exists, else
* - create a new configuration file (create_default_config) **/
cfg_file = loadconfigfile(the_cfg);
if (!cfg_file) {
fprintf(stdout, "Error: Configuration File \"GPAC.cfg\" not found\n");
return 1;
}
/** Fetch url from the command line **/
url_arg = argv[1]; // url as input, it takes the second argument from the command line
/** Modules manager
* - gets the absolute path to the modules directory
* - constructs a module manager object
* - loads modules **/
fprintf(stdout, "Loading modules\n");
str = gf_cfg_get_key(cfg_file, "General", "ModulesDirectory");
user.modules = gf_modules_new((const unsigned char *) str, cfg_file);
if (user.modules) i = gf_modules_get_count(user.modules);
if (!i || !user.modules) {
fprintf(stdout, "Error: no modules found in %s - exiting\n", str);
if (user.modules) gf_modules_del(user.modules);
gf_cfg_del(cfg_file);
return 1;
}
fprintf(stdout, "Modules Loaded (%d found in %s)\n", i, str);
/** Assignation values for GF_User object
* - GF_Terminal takes GF_User as its parameter **/
user.config = cfg_file;
user.EventProc = GPAC_EventProc;
user.opaque = user.modules; // dummy in this case (global variables) but must be no-null
/** Load terminal
* - Creates a new terminal (new scene for the compositor, new download manager, net services)
* - load terminal **/
fprintf(stdout, "Loading GPAC Terminal\n");
term = gf_term_new(&user);
if (!term) {
fprintf(stdout, "\nInit error - check you have at least one video out and one rasterizer...\nFound modules:\n");
list_modules(user.modules);
gf_modules_del(user.modules);
gf_cfg_del(cfg_file);
gf_sys_close();
return 1;
}
fprintf(stdout, "Terminal Loaded\n");
/** Output driver verification - whether these entities exist for output
* - Video
* - Audio
* - MIME file **/
str = gf_cfg_get_key(cfg_file, "Video", "DriverName");
if (!strcmp(str, "Raw Video Output")) fprintf(stdout, "WARNING: using raw output video (memory only) - no display used\n");
str = gf_cfg_get_key(cfg_file, "Audio", "DriverName");
if (!str || !strcmp(str, "No Audio Output Available")) fprintf(stdout, "WARNING: no audio output availble - make sure no other program is locking the sound card\n");
str = gf_cfg_get_key(cfg_file, "General", "NoMIMETypeFetch");
no_mime_check = (str && !stricmp(str, "yes")) ? 1 : 0;
Run = 1;
/** URL connection
* - terminal connects URL right away
* - while URL is connected, stay connected until user type 'q' to quit **/
char *ext;
strcpy(the_url, url_arg);
ext = strrchr(the_url, '.');
fprintf(stdout, "Opening URL %s\n", the_url);
gf_term_connect_from_time(term, the_url, 0, 0);
while (Run) {
if (!gf_prompt_has_input()) { // avoid getchar to block the application
gf_sleep(rti_update_time_ms);
}
c = gf_prompt_get_char();
if ( c == 'q' ) {
Run = 0;
}
}
/** URL disconnection
* - disconnect the URL
* - delete the application (close the main service, stop Media Manager, delete scene compositor)
* - destroy Module Manager
* - destroy the configuration file or save if needed **/
gf_term_disconnect(term);
fprintf(stdout, "Deleting terminal... ");
gf_term_del(term);
fprintf(stdout, "OK\n");
fprintf(stdout, "GPAC cleanup ...\n");
gf_modules_del(user.modules);
gf_cfg_del(cfg_file);
fprintf(stdout, "Bye\n");
return 0;
}To create and use a terminal, include/gpac/terminal.h file needs to be included. It contains all terminal prototypes.
If GPAC is installed on a LINUX distribution, the file config.h, present in the GPAC folder, is no more needed. Instead, the file gpac/configuration.h has to be included (like in WIN32 applications).
GF_User user: User object, contains user information needed by GF_Terminal for terminal creation (situated in include/gpac/user.h)
GF_Terminal *term: Terminal object, contains various information including scene compositor, media manager, frame duration, net services.
GF_Config *cfg_file: Configuration file object, contains information that can be found in the configuration file, as well as the file name and its path.
Bool Run: a boolean to indicate the application's state.
char the_url: url as input
Bool no_mime_check: a boolean to indicate MIME type checking
- Initialize various objects: user, url and configuration file.
- Load the configuration file if exists. Else a new one is created (a call to
gf_cfg_new, which takes the configuration filename and path as parameters. It returns a Configuration File object). - Fetch input (a url) from the command line (second argument).
- Load Module Manager:
(a) Fetch the absolute path to modules directory
(b) Create a Module Manager object
(c) Load modules from the modules directory. If no modules is found, return error and terminate application. - Assign value to user object for terminal creation
- Load terminal; create a new terminal (a call to
gf_term_newcreates a scene for the compositor, Download Manager, as well as net services) - Verify output driver: check for video, audio and MIME type fetch
- Connect URL:
(a) Terminal connects the URL right away upon callinggf_term_connect_from_time(by specifying the start time to 0)
(b) While the URL is connected, it stays connected until user types 'q' to quit the application - Upon '
q' reception from stdin, quitting application:
(a) Disconnect url
(b) Delete application (close main service, stop Media Manager, delete scene compositor)
(c) Destroy Module Manager
(d) Destroy configuration file or save it if needed - End